Toyota Three-Link

[Rocker]

Hi, my name is Rick and I just registered for this forum. I have been working on a three-link for my Toyota for about 4 months now and I finally got to a "drivable" point. As you all know, that just means now I have many bugs to work out, the main one being the driveline.

My problem is that I put a 9" rearend in the truck and with the max travel available with the suspension, the driveshaft obviously plunges more than the stock leaf spring suspension plunged. So, I needed a new driveshaft that would adapt to the 9" and have a slip yoke. Now the problem is that the force needed to cycle the slip yoke joint is more than what is needed to flex the carrier bearing (by the way it is a 94 X-tra cab, 2wd, 4cyl) so instead of the slip yoke moving, the carrier bearing does.

This brings forth many other problems, the flange bolts on the flange that bolts the two driveshaft pieces together cycles forward and jams into the carrier bearing metal case making an awful grinding noise, the driveshaft vibrates because I think it is not held in the center of the carrier bearing (the driveshaft is balanced and in-phase so I don't think that is the vibration)

Basically, I was wondering what you guys with big travel suspensions with a lot of plunge in the driveshaft (linked or leaf springs) and with two-piece driveshafts are doing to keep your carrier bearing rigid (aftermarket, from a different truck...?). I already tried filling it with silicone and letting it dry for four days (recommended by the driveline shop in placentia). Didn't seem to do much, could be that it hasn't dried fully because of the cold weather but I don't know, thats why I am posting this. Help!

[matt_helton]

a "well designed" 3 or 4 link set up should plunge very little. way less than a leaf set up. how much plunge are you getting with your set up? i wouldnt want any more that 3/4" to 1". and if your shafts bolt flange is contacting the carrier bearing housing and goint metal to metal maybe the rear portion of the shaft is too long?? and i would think that a well greased slip yoke should travel quite easily, no?

im not sure i understand the carier bearing rigidness issue. all the bearings ive seen on yota are mounted pretty securely.

and are you refering to OC Driveline?

[McClintock]

I would agree with Matt that your driveshaft might in fact be too long. How long is your driveshaft (2nd) in comparison to your trailing arms?

[Rocker]

The problem is that it is "well designed" for geometry which only allows for a certain different mounting points along with limitations due to the stock frame so the driveshaft plunge suffers. There is -2" plunge from ride height to bump and +2" plunge from ride height to droop. I know 4" is alot but they make slip yokes much longer than that so it is not a problem in that department.

The reason the bolt flange is contacting the carrier bearing housing is because the carrier bearing is so flexible that the shaft thrusts it towards the front of the truck before the slip yoke starts moving.

I am aware that the shaft is too long because it needs 2" of plunge from ride height to bump and it only shows about 1.5" at ride height however, this problem occurs driving on the street, I have not even came close to bottoming it out yet because I haven't off-roaded it because of this problem. Its almost like the carrier bearing is thrusting forward on torquing of the drivetrain because like I said, the slip yoke has at least 1.5" showing and there is no way I am using that all driving on the freeway to school.

The mounting of the carrier bearing housing is very rigid, the problem is the actual bearing riding on the driveshaft that is vulcanized to the rubber. That rubber is very flexible and moves all over the place.

driveshaft at ride height = 36.5"
Upper link = 35"
Lower link = 47"

you can kind of see in the picture where the crossmember that mounts the carrier bearing is in relation to the upper link mounting point and the lower link mounting point

[matt_helton]

4inches!!!!!!!!!!?????? holy crap.

uhhmmm....

first off, why did you mount the lower links off the front of the axle rather that from under the axle housing? that puts a ton of load(leverage) on the upper link, as the weight of the truck tries to twist the housing forward. im not sure but this mounting point might play into your plunge issue.

but 4 inches......man something is out of whack...

ill stop posting and let some more qualified people respond here.

[singlehanded]

Who well designed the kit and how much travel are you using?

[ntsqd]

Linkage Design Excel file (http://home.earthlink.net/~triaged/Files/4BarLinkV2.1.zip )

[Rocker]

Yes, it has 4" of plunge, I know its a lot but since I designed the suspension for good geometry I didn't care what the plunge was because they make slip joints like 12" long and it is not like how much plunge the driveshaft has affects how the suspension handles. It is irrelevant anyways because the thing could have 0.125" of plunge and it still moves the carrier bearing forward rather than moving the slip joint. I think the problem may be that it has a slip joint at the tranny, the carrier bearing moves, and it has a slip joint on the two-piece.

I put the links off the front of the axle because I was trying to get the roll axis negative so that the truck would have roll understeer. And since I was limited by all the other points (assuming I didn't make the upper link mount a foot off the top of the axle), the only place to get this was by mounting the links off the front off the axle.

That position might be causing it to have a lot of plunge as well as other adverse affects but the amount of driveshaft plunge is not my problem. The problem is that the carrier bearing plunges rather than the slip joint in the driveshaft.

Myself and my coworker here at Donahoe well designed the kit and the 4" plunge measurement is with 24" of travel (15" bump, 8" droop). I don't plan on using all that, but those are the max conditions.

I used that excel file and solidworks extensively to design the suspension characteristics including geometry, pinion angle change, but I guess I left out the plunge huh :) let me try to find the version with my final design and you could check it out

[slimjim]

Is the carrier bearing new? If it's old, then get a new one. If you are getting a new driveshaft, then get a bigger one too. The rubber gets worn out and more flexi. Sounds like yours is worn.

Slip yoke in the tranny is not optimal imo. If the carrier bearing is mounted on a cross-member, and there is a slip joint rear of the carrier bearing, then the front shaft should not move, and you don't need the slip on the tranny. That could be changed.

[Ramsey_ElWardani]

The main reason for keeping the Slip Joint change to a minimum is that under torsional loading they have a hard time "slipping" and tend to bind. That binding is what is causing your carrier bearing to be forced back and forth.

“Myself and my coworker here at Donahoe well designed the kit and the 4" plunge measurement is with 24" of travel (15" bump, 8" droop). I don't plan on using all that, but those are the max conditions.”

Just imagine coming off a jump, on the gas, and landing instantly using all of your 24 inches of travel, and jamming that torsionaly loaded slip joint in all 4 inches in a heartbeat. Something’s got to give. Just see how fast you can plunge it in and out by hand without any loading and you’ll get an idea of the forces at play.


I’ve seen where that binding is bad enough to break transmission and transfer case housings. You need to reduce the amount of plunge. As an aside; without going into too much detail, when John Marking’s Viejas Class 1 car was using plunging axles, they would bind enough to restrict suspension travel.

[curt]

I thought most people went to a single piece driveshaft in a long travel situation. I think it might be the relationship of your front mounting points on the lower arm vs the pivot of the driveshaft. I'm guessing that the driveshaft bearing is behind the front lower mounts and it is trying to convert the angle change to plunge. This is a total wild *** guess but could easily be checked by running a tape from the pinion flange to the output shaft and cycle it. The difference would be an approximate plunge if you had a 1 piece driveshaft. To reduce plunge you would need to get the front pivots and the driveshaft pivot somewhat close together. Plunge is bad, it's not a bearing surface that moves easily and will fight everything you do, shock/spring tuning as well as the high breakage factor...

I have a 4 link on a 94 STD CAB factory frame and the plunge over 18" is about 3/4". The U-Joint angle differences is about 2-3/4 degrees at worst.

I'm not saying it's perfect but it handles well over most terrain and the only thing I'm still struggling with is- forward bite and a loose on corner exit condition which should be somewhat correctable with more spring and shock tuning. Oh, if I only had a mountain of Eibach's to play with...Curt

[Rocker]

I explored the option of removing the slip joint at the front of the transmission and converting it to a yoke. That is my last resort as the shaft goes almost all the way through the tranny and it is hardened so it requires taking the tranny out, entirely apart and drilling the shaft in order to attach a flange to. If I can't fix the carrier bearing, then I will have to do that, but for now, it is last resort.

I went back to the Driveline Shop (across from Home Depot) and ray and I talked about making a more rigid carrier bearing. I am designing it right now and trying to figure out how I am going to do that.

I see what you guys are saying about the difference in force needed to plunge the slip joint versus the carrier bearing as that is what is causing and will always cause this problem until I either fix the plunge amount or isolate the rear slip joint as the only one in the driveline.

One piece is out of the question because it is an extra cab and it would be very long as well as have clearance issues from the crossmember on bump because the frame is brought up 4"

I read a while back when I was researching this problem that Scott from PCI prerunner was running a two piece driveshaft. If you read this thread scott, kinda off curious what you are doing for your carrier bearing (fully custom, big factory one, not to much plunge)?

P.S. The carrier bearing is brand new with the driveshaft I had made, no more than 350 miles on it.

[Rocker]

Thanks for giving a reason why plunge was bad curt, everyone just kept saying it was too much but I saw no reason why there could not be that much as long as there is a slip joint made with that much travel, but I now I kinda see a problem, not sure how big of a problem it is on a little toyota though....

[FullsizeFun]

I would have spent a lot more time on the CAD, and make sure everything works within a tollerable range. You cant have everything perfect, but you have to make adjustments to make it all work together. The 4-link I designed has .5" of plunge, 3.5* of pinion angle change over 25" of travel.
Moving your pivots 1/2" or changing the length 1" makes a big difference.

[curt]

not sure how big of a problem it is on a little toyota though....
Suspension bind points are to be avoided at all costs. A good working 14" of travel will outperform 25" of poor travel. Don't get hung up on travel numbers, make whatever you have work well. On a Toyota with a stock frame the upper will theoretically be the suspension limiter. In reality, it was the front U-Joint that limited us to 18" of travel without spending the big bucks for a CV jointed or double cardigm<sp> driveshaft. In off road, durability should always be considered the first priority, cause walking just plain sucks.

I'm not a 4 link expert like Dalton8 or any of the big fab guys but from what I've picked up is:
Work the plunge to less than an inch or so.
Keep the angle differences to less than 4 or 5 degrees.
Mount the lower shock mount at least an inch below the centerline of the front and rear pivots of the lower arm to reduce arm flop.
In one of the other 4link posts I believe Dalton said the upper arm should be about 60% of the lower arm length...Look for the long 4link thread for verification and read the whole thing, there's a lot of good data...
THEN play with all the angles slowly to tune in whatever other characteristics you are looking for.

Find a shock god for advice, there's more speed in shocks than any of the other stuff...Find Mike Arthur or talk to Brett King

I would hit the drawing board again. I believe you should start with the axle mounts, the should be more at 4 or 5 o'clock than where you have them. Your picture is too hard to see very well but your upper link mounts are in about the same place as mine front and back. My links are about 34" top, 52" bottom if that helps...Just my .02 Curt

[Rocker]

I am not trying to get hung up on travel numbers simply so I can claim that I have 24" travel, and I don't plan on using that much anyways, the problem is, before I did this, the truck sat with 10" of uptravel at ride height, then I brought the frame up 4" and I wanted it to sit an inch higher, therefore I will have, no matter what, no other options, 15" of uptravel at ride height unless I lower the truck which means the front will have like 5" of uptravel (no good), so from there I can get as much droop as I want from 0" to 8", I would rather not limit the travel to lets say 19" because then I will only have 4" of droop at ride height and the truck will handle like ****.

I played with the CAD a lot, changing designs and what not, I got the pinion angle to only change like 2 degrees but I never even considered the plunge of the driveshaft because I had been told not to worry about it and design for geometry. I guess that is the flaw in my design, oh well, thats how you learn.

I think before changing pivot points and link lengths, I would look into relocating the carrier bearing and having a new front and rear driveshaft made because if that is possible, it would be way more logical than changing the suspension. I do realize that a 1/2" or 1" hear and there will make a difference however the problem is if I change say the lower link points 1", that means a change in my geometry with other possible negative characteristics, a change in the actual links (or screw the heim out an 1" which is no beuno). Just seems like a lot of **** to change something that I thought and have been told by driveline shops and others that shouldn't be a problem, but hey, who knows.

The carrier bearing still needs to be fixed because as I said before, whether the thing has 3/4" of plunge or 4" of plunge, it still moves the carrier bearing before the slip joint moves.

[ntsqd]

What is the distance from the fwd most UJ CL to the pinion UJ CL? What is the length of your lower control arm CL to CL? If those aren't reasonably close then eliminating the bearing may not do you much good.

FWIW, a friend of mine is having similar trouble with his yota carrier bearing and he's running leaf springs. One thing to watch out for is filling the slip-spline with too much grease. Yotas tend to hydro-lock if you do that. Other brands must have bigger vent holes or something. I plan to keep the bearing on Patch b/c of the added clearence (not exclusively a Pre-runner). Have been comtemplating replacement designs as the lifespan of the rubber part is short and they're overpriced for how long they last.

[Rocker]

What is reasonably close? I will take exact measurements when I get it into the shop tonight. Is that what is desired to minimize driveshaft plunge?

When I went to the driveline shop yesterday we took out the zerk fitting on the slip joint and cycled it to make sure it wasn't hydro-locking because that is what he thought too.

[JESSE_at_TLT]

If your suspension geometry is good (except for driveshaft plunge), I would think that relocating your carrier-bearing should make a big difference. Denunzio used a custom carrier-bearing and two-piece driveshaft on the 2WD 5spd transmission in their Tacoma (http://denunzioracing.com/projects/tacoma/index.htm). Call Herman at (800)622-3939 and ask him about what they used. I don't remember if it was from a driveshaft shop or something adapted from an industrial application, but it works pretty well.

[ntsqd]

What is reasonably close? I will take exact measurements when I get it into the shop tonight. Is that what is desired to minimize driveshaft plunge?

That would depend on your linkage geometry. If the lower link's housing pivot were exactly concentric with the pivot point of the pinion UJ, then the ideal frame pivot location for the lower link would be concentric to the UJ at the trans. Note that "Ideal" in this case only refers to plunge and not other considerations.

[Donahoe]

Rick----Walk Down the hill my son.

[Rocker]

I am in the process of walking right now Kreg, thanks! :)

I am at my dads shop measuring some stuff for relocating the carrier bearing to fix this problem and I got a new carrier bearing from the driveshaft shop today, one of those big ones off of I think its a Chevy, lots of rubber for vibration isolation, but it does not move laterally hardly at all, I think that should be a good start. I am going to relocate it and minimize the plunge but there is only so much I can do without relocating pivot points of the links.

What are you guys who have Toyota's that are linked running for plunge? All you esb guys, fishdood, that silver tacoma, bk fabworks, giant if you have done any toyotas. I just want to get an idea what you guys with TOYOTAS THAT ARE LINKED are running for plunge, thanks for all the info so far, its given me a lot of insight and I need as much as I can get.

[CHASE550]

Rick----Walk Down the hill my son.

We gotta Luv ya Kreg

[elcaprerunner]

Rick, don't walk down the hill, if you do he's gonna try to cut your hair! :)

[twillis]

Does any of this apply to a 62" leaf conversion? I've got an '01 and am going to convert from the standard Deaver 7-leaf replacement pack to the 62"s underneath a T-100 axle. Looks like that setup cycles up about 3" higher due to the flipped spring perch.

[partybarge_pilot]

Going to longer leafes will probibly give you less plunge. The closer you get the front half of the leafes to the lenght of the driveshaft the better of you are. All stock trucks have DS that are longer than the front half of the leafs.

On the 3-link, your DS should be alot closer to the lenght of the bottom links.

[Gordon]

In the rock crawling world, a lot of people use two piece drive shafts in the front. Those rubber mounted bearings just don't work, so most people change to a simple pillow block bearing from an industrial bearing supplier. I don't know how this would be for vibrations/ durability at high speed though.

[Rocker]

Gordon, that was my original idea, to use a self aligning bearing that mounted solid to the frame, however, that was my first thought was how a solid bearing would handle the vibration. I concluded probably not to good seeing as that it is a daily driver and I take it on the freeway for about 30 miles to school 4 days a week, I didn't think that was to great of a solution. So I got a carrier bearing from some chevy which has a lot higher durometer rubber than the stock joint and I am going to relocate it further forward to reduce the plunge. I have to go so far forward the front piece of the driveshaft will probably end up only being about 18"!

This will bring all sorts of other problems into the picture such as max driveshaft length, anybody know what it is? The driveshaft hitting the original carrier bearing crossmember on bump. But after cutting the rear frame off and rebuilding the truck from the cab back, whats a little crossmember clearancing? :)

I still haven't heard from any of you guys with Toyotas that are linked as far as how much plunge you guys are running, just curious as to how much I can reduce the plunge working with the limits of the stock toyota frame for the link mounting points.

[partybarge_pilot]

The T100 that JD did has about .5" total. You can see some pics of it on there web site.

[JESSE_at_TLT]

That T100 by JD Fab is one of my all-time favorite Toyota build-ups.

[Rocker]

Okay, so I took some measurements off my solid model in Solidworks (tried to post a .jpg of the screen shot but it wasn't working) and the pinion plunge is 0.88 inches. I thought this was pretty promising because I figured that it would, from here, be easy to figure out where the forward U-Joint CL would need to be in order to minimize plunge. Basically, I drew three points at the rear U-Joint CL, one at bump, one at ride height and one at droop. From there I got out a compass and started playing with points to see where the least plunge was.

The UJ CL has to be so far forward to even come close to matching the lower link length which still only reduces the plunge to about 1.5-2.0" that I am now thinking of going to a one-piece driveshaft and simply clearancing the crossmember and the cab if necessary. I was wondering if any of you guys with toyota x-tra cabs are running one-piece driveshafts or if it is too long. I know there has got to be some sort of length limit that driveshafts can be built to and still operate properly (as far as vibration goes). Any feedback would be helpful, thanks.

I will restart my computer and try to get that jpg to post.

[Rocker]

I looked at the truck today in furthur detail and I am pretty sure a one piece won't work, back to the drawing board. Since I have to relocate the carrier bearing, I am getting a completely new driveshaft made to accomodate the new location of the bearing.

The driveshaft guy is trying to sell me on this idea of making the front piece of the shaft (the one coming out of the tranny and contains the carrier bearing) end with a spline joint rather than a flange. From that spline, the slip joint goes over the splines and then goes to the UJ of the second piece and onto the UJ at the pinion. Kinda hard to explain, basically out of the tranny it goes:

UJ - shaft - carrier bearing - spline - slip joint - UJ - shaft - UJ

Rather than the stock Toyota setup which goes:

UJ - shaft - carrier bearing - flange - flange - UJ - slip joint - shaft - UJ

I am hesitant to go with this setup because rather than the slip joint being in line with the second piece of the driveshaft (how it is now), it is in line with the piece coming out of the tranny, so when the suspension cycles, the force coming up the second piece of the driveshaft has to shift angles to horizontal to plunge the shaft coming out of the tranny. Any opinions???

that was hard to explain, if you can't picture what I am saying just let me know and I will try to clarify.

[CHASE550]

I posted a pic that i just hacked together of what i believe rocker is basicly talking about and it sound to me like this could bring lots more problems them the regular way, but at the same time its plunging like a one piece would so ???

[Rocker]

That is exactly what I was describing except for on the trans side there is still a slip yoke going into the tranny but other than that exactly. It just seems that the force of the second piece of the driveshaft would want to push up on the spline and carrier bearing rather than pushing it in and out (forward and back).

Trent, that is the way the stock shaft plunges, that is a good point for doing it that way, it is also less parts to vibrate, fail, or whatever. I never thought of that.

It also will reduce my driveshaft angle by moving the carrier bearing forward and the shaft will have less tendency to want to push up on the splines and the carrier bearing. I don't know.....any of you guys have experience with this kind of setup??

[roscoe]

redesign your three link is the first thing to do

just my ten cents

[racer951]

Just saw Jesse's post and dug up a couple pictures of the Denunzio drive shaft. Not sure if this will illustrate what he was trying to say.

[Rocker]

Redesign my three link is what I should do first?!?

Well since you don't know anything about how the three link is designed as far as geometry, pivot points, roll steer, pinion change and things like that, and you haven't driven it to see how well it handles, I think that is kind of rash judgement don't you? The only thing you know is that it has 4" of plunge. That is simply a function of where the carrier bearing mounts stock. Unless my lower links were only about 36" long, its gonna have a lot of plunge. Thats why I am curious what these guys with ESB kits are running for plunge. I am in the process of relocating the carrier bearing to cut that plunge number down by about 75%.

I am not an idiot and didn't just decide on my first fabrication project that I would attempt to build a three-link and design a shyst ass one (I guess some would disagree but there is always those types). I don't claim to be master fabricator but I have just a little experince doing this, I just had never tackled a complete link set-up before. I simply addressed the application of the truck before I started building it. It is a daily driven street truck that sees dirt 1% out of 99% that it is driven, therefore, I really wanted to get the geometry real nice so it wasn't a handful to drive at 80 on the freeway or in the dirt on the rare occasions I am in the desert. Sooooo, it was more important to make the thing stable and not track all over the road than to be able to say "I only have 0.030" of driveshaft plunge over 35" of travel, and that **** is sick dogg!" I got that part done and now I simply have to redesign a driveshaft that was engineered for a leaf sprung truck with 10" of travel MAX. And if I can only get the plunge down to about 1.5" over 24" of travel, then so be it, I know I have tried everything else, everything is a compromise and believe me, I tried numerous different designs, cycled, calculated and ran some numbers and this is what I came up with. It is not something I threw together overnight, that's cool if you think it needs to be redesigned, everyone is entitled to their own opinion, however wrong it may be :)

[Rocker]

Racer 951, that is pretty much what I am talking about. I decided against that because I would rather see the plunge joint directly in the line of force rather than horizontally coming out of the transmission. It also makes it so I don't have to move the carrier bearing really far forward to get the UJ CL in the same place as if I just ran a flange after the carrier bearing.

[matt_helton]

PM esb4130. he should be able to give you the info you need.

[Rocker]

I should have thought of that a while ago, thanks matt

[BigAaron]

I agree, how long do you think that slip yoke will last moving in and out 4" while on the gas going through whoop sections. I give it about 10 miles before something breaks.

[DuffcoDan]

I worked with Jim at JE Reel Driveline to build a custom drive line to work with a linked toyota. they have built drivelines for Robby Gordon's truck with 3/4" of plunge and the Baldwin's truck with 6" of plunge. he mentioned that some set-ups he has seen shouldn't even work when you put it in on paper, but end up working out on the vehicle. I would be most concern about what point in the travel you are getting the most change in driveshaft length. If you are getting the greatest change at the extremes of the travel then it is only ridding there for a moment. I originally designed the truck with a one piece shaft to get 11/16" plunge in the last 4-6" up out of 26" travel. If it helps at all the links are 41" and 52". The main concern with the one piece shaft was that the transmission tailshaft bearing can't handle the thrust load of over 2 feet of travel. I have since went to a two piece shaft with a chevy full-size carrier bearing encapsulated in a urethane mount. this has shortened the driveline by about 18". the slip portion of the shaft is closest to the third member. I have not checked the plunge with the shorter shaft, but I am guessing it will be more.

[matt_helton]

earlier you mentioned notching the cross member to clear the prop shaft......here ya go...lol....looks like hell but works.

[Rocker]

Well, the carrier bearing has been relocated, just took measurements and I am off to the driveshaft shop tomorrow to get the new shaft made.

Dan, when I was taking measurements at droop, ride height and bump, I realized and thought about what you said (where the plunge is the greatest). From ride height to droop (8 inches) and from ride height up 8 inches, the plunge is only 3/4". The last 7 inches of bump it increases however, like you said, its not constantly in that area of the wheel travel so it is not as big of a deal. I still realize that I will be in that zone of travel some of the time, however, there is nothing I can do to lower that plunge number so thats my design and I am sticking to it.

P.S. Baldwin's truck has 6" of plunge? Is it a one piece or a two-piece driveshaft?

Also, where did you get the urethane encapsulated carrier bearing? I have a carrier bearing off of a chevy that I am taking to the driveshaft shop tomorrow but it would be great if I could upgrade it to a urethane one as well before he builds the new shaft.

[DuffcoDan]

I had the driveline made by JE Reel. they are the ones to talk to about the HD carrier bearing. I believe it was $70. the stock part must be interchangeable with the urethane one, so you could always upgrade if it gives you a problem. I have a picture if you want to check it out.

it sounds crazy but the baldwin's truck required a custom made slip yolk to alow for six inches of plunge. I don't know if it was one or two piece though.