Eyeball my pinion angle please

dtroth91

dtroth91

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orange county
Chasing a vibration after installing 4 inch rock jock lift on a tj unlimited.

Can't seem to find a good place to measure tcase output shaft angle(any suggestions?). I probably should have done it when I removed the shaft. I did this to isolate vibrations to rear driveshaft.

I was starting to hear a small clunk which I attributed to u joints because it happened when taking off from a stop (though not always).

1. Is it possible I have the angle right, and the vibration is coming from the u joint?
2. What do you think of this just from eye balling it? Not good enough?
Or is it both and I have to fix the u joints before being able to tell if I can get the angle dialed in..

Currently trying to get away with no SYE as you can see but I do have one laying around from an old zj I planned on building. The only thing stopping me from slapping it on is that the wallet is hurting a bit right now and i dont really want to toss another few hundred at a driveshaft (yet).

EDIT: uppers are as short as I can get them, so the pinion isn't going down unless the axle goes back

20200914_154540.jpg


20200914_154548.jpg
 
Thats what I figured at this point, but for the wallets sake I figured it was worth asking. I think I've read some people with unlimiteds can get away without. Perhaps I read wrong or just no such luck.
Thanks
 
dtroth91 said:
Thats what I figured at this point, but for the wallets sake I figured it was worth asking. I think I've read some people with unlimiteds can get away without. Perhaps I read wrong or just no such luck.
Thanks
Click to expand...

The key phase is "get away with".
 
You can check your t-case angle by setting the output yoke to 12/6 position and placing an angle finder on the flat part of the yoke. You can do the same thing on the pinion yoke and that will give you your angle difference, if any. It is hard to tell from the picture but it looks like you have more angle at the pinion yoke than the t-case yoke which may be contributing to the vibes. If that is the case, you may need to lengthen the rear uppers to bring the pinion and t-case closer to parallel.
 
dtroth91 said:
Thats what I figured at this point, but for the wallets sake I figured it was worth asking. I think I've read some people with unlimiteds can get away without. Perhaps I read wrong or just no such luck.
Thanks
Click to expand...

Sometimes you can.

It's need to be set like this (bottom one) if you weren't sure.

Pinion Angles.jpg
 
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Once you have measured the angles you can do a skidplate drop (I noticed your skidplate is in the stock position) of 1-2" to temporarily alleviate the vibrations until you can afford to install the SYE.
 
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Thanks for the responses.

After setting the yoke to 12 and taking a reference angle to use for the pinion i was able to get what I 'think' was optimal and still felt some pretty noticeable vibes.

PO had put TC drop in that i removed since I thought I wouldn't have any issues. I could put it back in to help but its no guarantee and I dont like taking a step backwards. I think I would rather fork up the dough and do it right.


Decided to pull the rear drive shaft again to be sure I had isolated it to the rear only.

Driveline was very smooth, no more vibes. I think its time to order a driveshaft. I believe I can use the SYE I have laying around. I just pulled it out of the plastic today.

20200914_172412.jpg
 
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For now, until you can install a SYE and DC driveshaft, drop the tcase 1" with a lowering kit which should stop the vibrations.

Do that or the SYE install right away, you cannot simply live with the vibrations which can take out u-joints, seals, and/or bearings.
 
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Thank you Jerry! I actually have the rear removed at the moment and am lucky enough to have a second vehicle I use when I can't drive the jeep. Ill be driving it til i can get a cv.

Thanks again everyone!
 
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A little update.

Stripped the torx at the rear and drilled it out and installed the angled bracket.

Tom woods custom shaft was ordered and received.

Working on the SYE install today.
Took lots of trips to stores for various things in addition to my early morning supply run. Should be able to finish the install tonight but adjusting the pinion and torqing bracket to spec can wait til tomorrow.

Install was fairly straightforward except a few hiccups.

Front driveshaft bolts at the tcase are actually 5/16s and not 8mm, almost stripped them and made my day worse. Luckily I stopped and started doing some research although common sense should have told me it was too much play for the bolt head.

I also forgot one of the golden rules which was to buy QUALITY snap ring pliers. I was able to make do and "walk on" the big one after some negotiating.

I also should have adjusted linkage cause it kept wanting to slip out of 4lo.

Good stuff otherwise.

Thanks folks
 
dtroth91 said:
A little update.

Stripped the torx at the rear and drilled it out and installed the angled bracket.

Tom woods custom shaft was ordered and received.

Working on the SYE install today.
Took lots of trips to stores for various things in addition to my early morning supply run. Should be able to finish the install tonight but adjusting the pinion and torqing bracket to spec can wait til tomorrow.

Install was fairly straightforward except a few hiccups.

Front driveshaft bolts at the tcase are actually 5/16s and not 8mm, almost stripped them and made my day worse. Luckily I stopped and started doing some research although common sense should have told me it was too much play for the bolt head.

I also forgot one of the golden rules which was to buy QUALITY snap ring pliers. I was able to make do and "walk on" the big one after some negotiating.

I also should have adjusted linkage cause it kept wanting to slip out of 4lo.

Good stuff otherwise.

Thanks folks
Click to expand...

Glad it worked out for you and I must say I've learnt a little bit reading the thread.
 
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