rlssteiner

Guys I need some help here, I have a 92 Jeep Cherokee Laredo 4.0 with a 4.5 RC long arm lift with 31" tires and currently after changing motor mounts(rubber) and transmission mount(rubber) my jeep has a vibration/shake. The TC shows it the worst, and when I go reverse and lightly press on the gas it shakes pretty good. For the life of me I can not figure out what it is.... Now when I changed the motor mounts I noticed I had to lift the engine up quite a bit to get the holes to line up. Any ideas or someone that might of had the same problem out there. I've searched the forums numerous times and have not seen anyone with a similar problem or fix. Thanks in advance!

4OHI6

Rubber or poly mounts?

rlssteiner

Rubber mounts, they were the cheapest from oriellys

4OHI6

If you cranked the through bolts on motor mounts really tight you should back them off a quarter turn and see if that helps. The bolts should be the flanged prevailing torque style and they will stay where placed.

Repeat to see if you can find the sweet spot to minimize the vibes.

rlssteiner

I'll give it a shot and post back the results.

rlssteiner

It's the same I forgot to mention before i changed all the mounts, I could feel a shake coming from the bottom while going reverse while giving it a little gas. I've took it to some mechanics and they won't even attempt to look at it because of the lift.

4OHI6

While moving or sitting still with foot on brake? If moving, inspect ujoints on front and rear driveshaft.

rlssteiner

Just sitting still and idling. I tried taking a video of it but it's hard to see the vibration.

4OHI6

can you post links to the mounts you used?

How many miles have you driven with these new mounts?

rlssteiner

http://m.oreillyauto.com/mt/www.orei...2327&ppt=C0019

Above is the link to the engine mounts I used.
As for miles maybe 20 miles at most.

rlssteiner

http://m.oreillyauto.com/mt/www.orei...2251&ppt=C0338

Te link above is the Transmission mount I used.

4OHI6

It sounds like the new mounts have magnified an existing vibration and made it more noticeable. Does it idle smooth or have a little bit of a miss?

rlssteiner

It idles smooth, i checked all vacuum lines replaced spark plugs, and wires. Also tested it to see if it was misfiring and no, it runs great just that vibration/shake is killing me.

4OHI6

Also have you checked the bolts on TC to Tranny and make sure nothing loose? Best to get under there and have somebody put in and out of reverse and see where its moving and then trace from there.

rlssteiner

Yeah all the bolts are tight. The metal bracket that the leafs springs sit on are rusted and bent like a moon shape, so it's letting the rear axle move quite a bit when put in reverse and back into drive... But as far as it shaking/vibrating at idle, I think that wouldn't be the reason.