LaredoBucket

Hello All,

I recently added a 1" RE TC Drop to my 2WD 92 5spd to get a better Pinion Angle. The rear of my XJ sits pretty high due to the 1.5" Lift Shackles and 3.5" RE Leafs. Now I have a vibration with i reach speeds of 45 mph. It's not Death Wobble, it seems to come from the drive line area. I keep checking the U Joints, by turning the drive shaft by hand, but it seems to fine with no play. I am thinking maybe Pinion Angle still needs to adjusted. OR, could my Motor/Transmission Mount be bad? One day I was under my car and shook the tranny, it seemed to move a bit, but I figured it was moving because of the rubber mount. Should it not shake or move at all?? Also, I do sometimes hear a clunk from the engine when I take off. Maybe bad motor mounts??

bobthecatkiller

Greese the drive shaft slip joint for the clunk to go away. Did you have vibes before the drop?

LaredoBucket

Yep, Greased them already. I didn't have vibes before the installation of my new leafs and coil springs. Maybe i need to tighten my u bolts on the axle?

cruiser54

Or replace the u-joints because they have a wear pattern from being in the old spot for so long.

93_xjcherokee

Or get rid of the tc drop and do it right

md21722

Yes to what cruiser said. I noticed my rear had a slight vibration when I changed the only saggy leafs with new ones. I'm sure the factory original u-joint had a wear pattern. It was only 320,000 miles new.

But before investing in all new u-joints I strongly suggest you get an angle meter and check your u-joint angles. With 5" of lift I'd think you could have angle issues even on a 92 5 spd which has one of the longer driveshaft setups. The longer the driveshaft, the less operating angle it will have and the more chance you have of being able to get the angles right without a full on SYE. The u-joint angle at the transfer case and pinion (rear axle) should be the same and the operating angle of the u-joints is as close to 3 as possible for the best u-joint life. I think up to 7-8 is still reasonable.

Do some reading on axle shims and SYE. Transfer case drops are not the greatest. They put your motor mounts under abnormal stresses, reduce ground clearance, move your exhaust hanger, ...

LaredoBucket

thanks! this makes sense. I recently replaced the rear u joint about 4 months ago, i guess it still could be worn. Im going to figure it out this friday and see what the problem is. The front U-Joint near tranny could be crapping out. I also ordered some new 1" Zone Boomerange Shackles to replace my crappy Rough Country 1.5" shackles and to drop the rear, and level it out a bit. Hoping it will help pinion angle. Right now the rear sits a good 1" to 1.5" higher than the front.

Fred/N0AZZ

Your signature shows you have a 2wd yet everything else says 4wd did you mean a 2dr.?

With that much lift 5" you need an SYE and shims not a TC drop kit the angle is way off. Most all lifts over 3 1/2" need an SYE to work properly and the right driveshaft as well. Anything else is just a Band-Aid to cover up problems. I had to go with Adj. U/L CA's at 4 1/2" to correct front differential pinion angle as well.

LaredoBucket

I have a '92, 2WD, 4 door, 5 Speed, H.O. 4.0L

The T.C. Drop was suggested by another CF User, so I gave it a shot to see if it corrected my pinion angle. It seemed to work because before installing the TC drop, I could hear the drive shaft making a "Pinging" noise, which has since stopped after installing 1" TC drop. Shims DO seem like a better option.

However, I believe this might be a combination of issues. When driving, accelerating to 35 mph, I get the vibes and when I let off the gas and push in the clutch, the vibes stop. So it may be Motor and trans mounts and maybe worn front u-joint... I really don't think the pinion angle is too far off because my previous lift was about 4"/4.5" of lift. I'm gonna install some shorter Zone Boomerang Shackles to see if that will fix the problem. I won't be able to thoroughly inspect till my day off or work on Friday. Thanks for all the help its very much appreciated!

LaredoBucket

Yep! That's what it was. Worn U Joints. I'm still going to lower the rear with some shorter ZONE Boomerang Shackles.

One more thing, I have a 8.25 rear end out of a 96/97 XJ. Are the U Joints the same size for a 92 D35 rear??

cruiser54

Yessir.

Now, a rear disc conversion is super easy with the 8.25.

Ever thought about the bigger booster and master cylinder?

LaredoBucket

Awesome sauce! I figured they might be the same size.

I've never considered the disc conversion. Is there a write up or link? I just want my XJ to run like a dream on and off road. I'm thinking of getting one of Rusty's Off Road Long Arm Kits next...
http://www.rustysoffroad.com/jeep-su...on-system.html
or
http://www.rustysoffroad.com/jeep-su...m-upgrade.html

Fred/N0AZZ

Humm I didn't know a 2wd even had a transfer case to drop

LaredoBucket

Tell me about it! I put the TC drop on the cross member to drop the tranny down an inch. But now that I found out my U Joint were bad, I may just take it out. I don't want to add stress to the motor mounts.

cruiser54

Discs: https://www.cherokeeforum.com/f51/re...-8-25-a-57807/

Booster: I can't find it right now. The booster is more effective than the rear discs.