[T-Nave]

Pinion angle vs Castor

Hello everybody. This is my first post on here. I recently picked up a 5.9 zj. Im going to put on an iro 3.5 with the pre runner shocks and rear track bar.
My question is will there be a sweet spot when I adjust the front cam? Last jeep ( cj7) I lifted I had to deal with a little driveline vibes and not quite enough caster so I didn't have one extreme or the other. Any help would be great.

 

[Utah_ZJ]

It's your caster adjustment, most reputable 4wd shops know where that sweet spot is and will align it accordingly, and you are going to have to upgrade the front drive shaft to a u-joint style setup.

 

[T-Nave]

Thanks for the reply. Im an idiot! I just realized what the title of the post said. I meant pinion angle vs. caster.

 

[jeeptech]

With 3.5" of lift you will need the caster to be lower than 4.0* don't set it to factory spec's the caster is too high and will give you death wobble. Try to keep caster as close to 4* as possible, it will give you the best driveability. Don't worry about the pinion angle, you would have to have negative caster to get any vibes. Do you have the cardon joint at the front axle or the rzeppa joint? The rzeppa doesn't allow for as much angular change and can give you vibes.

 

[T-Nave]

My front drive shaft has a double cardon at the t-case and a rzeppa at the axle. I plan on changing it soon. I just want to get 1 trip to the sand dunes with it first. Im trailering it so hopefully it will stay together for me?

 

[jeeptech]

The Rzeppa joint is very weak so go easy.

 

[Utah_ZJ]

Thanks for the reply. Im an idiot! I just realized what the title of the post said. I meant pinion angle vs. caster.

Don't ever call yourself an idiot, you are just new to most of this stuff and learning.

 

[Big Red]

That's right don't be so hard on yourself man! You bought a 5.9L Grand Cherokee so you are very smart actually...like me! LOL

I have that same stock driveshaft on my ZJ with a Clayton long arm LP30 with 6.5" lift and it has done good...I haven't wheeled it yet and going with a built HP30 now and Ford 8.8 and 5" lift and 33s.

I have a few XJ front driveshafts that I would like to use but they need to be cut down a bit to use up front. I loved being axle to carry 1 stock XJ front driveshaft and use in the front or rear of my 4.0L/auto/241 Rubi t-case with the SYE on it...Those were the days with my XJ on 37" MTRS HP44/9" and 8" drop bracket RE adj short arms...owned the Rubicon!!! ;-)

Troy

 

[Utah_ZJ]

That's right don't be so hard on yourself man! You bought a 5.9L Grand Cherokee so you are very smart actually...like me! LOL

I have that same stock driveshaft on my ZJ with a Clayton long arm LP30 with 6.5" lift and it has done good...I haven't wheeled it yet and going with a built HP30 now and Ford 8.8 and 5" lift and 33s.

Troy

How do you know it has "done good" if it hasn't even been on the trails?

 

[T-Nave]

Well I got the lift done a couple weeks ago. I adjusted the cams to get the front pinion pointed at the t-case as much as possible. It is pretty close. Caster doesnt seem to bad either .Took it the sand dunes and wheeled the hell out of it for 3 days. This thing is a ripper for being stock under the hood !

 

[johnsjeep]

You said you set your pinion to point at the transfer case? Shouldn't the pinion point straight back and the transfer case straight forward? I lifted my WJ and cannot find a shop around me that even measures the front pinion angle so wondering how I could measure it my self then I could have the caster adjusted.

 

[Utah_ZJ]

You said you set your pinion to point at the transfer case? Shouldn't the pinion point straight back and the transfer case straight forward?

Sounds like a great way to blow up your drive line. Google some pinion angle diagrams and you will see why it is important to point the pinion toward the transfer case.

 

[85IrocZ-28]

You said you set your pinion to point at the transfer case? Shouldn't the pinion point straight back and the transfer case straight forward? I lifted my WJ and cannot find a shop around me that even measures the front pinion angle so wondering how I could measure it my self then I could have the caster adjusted.

I believe that is the correct way to do it if you have a single u-joint at each end. But with your driveline, the Pinion should be pointed up towards the t-case. The t-case isn't really adjustable, so it will point straight forward. I haven't ever measured the pinion angle. I just do it by eye.

 

[T-Nave]

Anybody running a double cardon joint at the t case should have the pinion pointed at the t case. If your running a single joint at each end of the drive shaft then you want the angles to run on the same plain. Both measurements can be plus or minus a few degrees. Anything else is a good way to get vibes and destroy joints and bearings.

 

[T-Nave]

You said you set your pinion to point at the transfer case? Shouldn't the pinion point straight back and the transfer case straight forward? I lifted my WJ and cannot find a shop around me that even measures the front pinion angle so wondering how I could measure it my self then I could have the caster adjusted.

There is several ways to measure the pinion angle. Google it and pick the one that works best for ya.

 

[johnsjeep]

Thanks guys, I did not know it made a difference having the 2 single u-joints or the double cardan on the one side. I had googled some images and the diagrams I saw were showing the axle pointing straight back but I probably only say the single joint.

 

[T-Nave]

Go to Tom woods drive shaft web site ( 4xshaft.com) and click tech info in the upper right corner. Probably the best right up Ive ever read on drive line angles.