Drive Shaft Angles

[TDI Guy]

Can anyone check there front and rear pinion angles and drive shaft angles from the flat bottom part of the 3rd members? I am trying to set mine up and since my truck is adjustable both in the front with the 3-link and in the rear with the RYM rear links, I want to have an Idea what to do. I have no clue.


Randy

[snuffer]

I don't know what angles I have but I lifted my D90 2 1/2 to 3"

The Rtym. trailing arms with both of the spacers on each side eliminated my driveshaft vibration.

I don't have any vibration from the front but have a set of their radius arms on the way to get the springs and bushings back to where they need to be.

[Chris Cox]

Randy, in the tech section there is a small write-up about adjusting the 3 link. They give you a length to start out with, and then you just have to play with the fine tuning.

[TDI Guy]

Where do you measure the angle from in the front?

[Chris Cox]

Did you install the rock guard for the 3 link yet? If so, put the angle finder on the bottom of it. Should be adjusted to around 2 degrees.

[TDI Guy]

Yes Chris, the rock guard is on. Would the 2 degrees be basically a stock castor setting?

As for the rear, If I set up the pinion for a standard d-shaft, it appears that the d-shaft angle is about 18 degrees at the joints. Isn't that too much angle for a standard joint?

IF I try to set the rear up for a CV style shaft, The links don't have enough adjustment to turn the pinion to point up to the t-case. Ahhh what to do.

[Chris Cox]

Yeah, 1-2 degrees would be a stock setting. Randy, keep in mind that those pinion angles are going to change once you get the truck completely together and loaded down. As for the rear, I am goind to have to think about that one.

[Chris Cox]

Randy, are you saying that you have -18 degress of castor? This would have the pinion pointing towards the ground, rather than towards the t-case.

[TDI Guy]

OK. Chris. 2 degrees under the rock gard would be about stock castor.

when I said 18 degrees, I ment the rear d-shaft angle at the u joi nts. That is what it is if set up for a standard d- shaft. Doesn't that seem too steep for standard u joints?

[Chris Cox]

Randy, I checked Tom Wood's site. It says that a standard u-joint will be OK to about 15 degrees, but you will have vibration more than likely. And that 15 degrees is only good if the t-case falnge and the flange on the pinion are parrallel. If they aren't, the 15 degrees figure decreases. I would contact RTYM in the a.m., and get some info. Hell, you paid good $$$ to fix this problem, so they should have the answers of why it is not getting you down below 18 degrees. Hope that helps some.

[redrover]

Randy, it sounds like you understand the basics of driveline theory. If you use a stock drive line in rear, you need the flanges/yoke to be in parallel. This would most likely mean making your trailing arms longer. BUT if you are going to use a double cardan style driveshaft, then you will want to turn diff upwards until it points at the transfer flange. Now I run ome764 coils with a 1.5 spacer. In my case, in order to have the rear driveflange zeroed out with the shaft I shortened my trailing arms so much that my wheel sat way forward inside wheelwell. I didnt like this setup for ideal rock climbing. The wheelbase is already to short to start with. So I had RTE send me a Disco A-arm extension. Now if you just install it as per instructions, it{A-arm } will rub on fuel tank. So I redrilled it. The new lower hole locations worked perfect. It tilted pumkin up about 5ish deg , it recentered my tire in wheel well , and there is no vibration. I sent some info to steve at RTE. There is about 3/8 clearance at tank, and that distance is a mile when cycling suspension. I will take some photos Mon. JP

[redrover]

Here is a shot. First I mirrored the origonal hole pattern measured from lower right side over to the left side. The new hole locations and notching do not compromise strength. Then I notched the lower right corner to clear the ball joint. I notched way more than nessecary.

[TDI Guy]

Thanks JP This is definately what I need...IT will cure my problem. What did you do it the front?

Randy

[Chris Cox]

That looks pretty good JP. Looks like I will need one of those also.

[TDI Guy]

Chris, I will let you know when I get the CD and send it back ASAP.


Randy

[TDI Guy]

Chris, just to let you know, I got my hands on a stock d-90 today to check some angles. If you check the front axle from under the rock guard, the axle is at a 16 degree pointed up to the t-case. As for the rear, from under the diff housing, the axle is twisted up 6 degrees.

Now this is a stock rig with no lift at all. Its a good place to start. I am going to set my front up stock without a d-shaft at first and work on the rear till I get no vibes. Then do the front.

[Chris Cox]

Randy, the 2 degrees is what we ususally setup on the rear. When I said 2 degrees in the front, I meant different than the angle of the driveshaft. You want your pinion angle close to the angle of the driveshaft. Sorry about not being clear about that. If you were running 2 degrees in the front, you would probably not be able to get a driveshaft on without having about 3 cv's:rolleyes .

Chris

[TDI Guy]

LOL.. Your right..

[redrover]

Hi Randy, I found some angles. In the back the driveline is 2.5 deg difference between the milled flat on bottom of diff and the shaft. My shaft angl is 15deg and the flat is 12.5. I dont know why but the angle finder reads 2 deg different if i turn it around 180-and measure. Measured this way 18deg and 15.5deg. I added a picture of the forward control arm mount. My arms were first generation, and I had to use a washer to prevent arm sucking up into bushing. The Front drive line was measured same way. I have a SG rockguard. the angle of my shaft is the same as the section of the rockguard that bolts into differential. The driveline angle was 18deg.

[TDI Guy]

JP.. Thanks, that really helps a lot. You are running CV shafts front and rear correct? What size are the rims and tires in the pic?

[redrover]

I am using cv style drivelines front and rear. The tires are a 315/75-16 goodyear and the rims 8x16. here are a couple shots.

[redrover]

RTE

[TDI Guy]

THanks again JP. I think I will need that arm extender from RYM. I have all the bushings out on the rear links but its not enough. I will have to wait till I get the truck almost together with all the weight in it anyway to let it settle first though.

Randy

[redrover]

Randy , another method of shortening control arms is to move your frame ear bushing to other side of frame ear. But it will deff move tire forward in wheelwell. Also may contribute to bumpsteer, although I never felt any. I tried this initially and went with the redrilled A-arm extension. JP

[TDI Guy]

I will prob. just go with the redrilled unit then.

[Abrooks]

Anyone have luck getting a defender-specific arm extension from Rovertym? Just put spacers (1") and arms and links on the truck and the rear pinion is still way too horizontal.

[Abrooks]

Bueller?

[TDI Guy]

Anthony, I think you would need the spacer from RYM. shoot JP an email he did it.

Randy