Hello,

Forgive the vague description in my subject line but this is the only way I can think of describing the experiences I have been having with my Jeep.

I have 93 Grand Cherokee, automatic, Quadratrac V8, 5.2L.

The problem is this:

1. While driving down the highway continuously approx. 20-30 minutes between 120 -130 - 140 kms/hr., I start hearing a grinding like noise; the sound is like when you drive over the edge markers on the highway (that gritty sound that tells you are going off the regular driving surface) or the sound you would get when driving over cat eyes in the road. The sound is coming from somewhere in the centre of the vehicle.

2. Shortly after this, I hear a faint whining sound which accompanies the grinding noise. The whining noise sound like when you hear a car’s transmission sound when it is reversing in a long straight line.

3. The pulling (mainly to the right) comes next. Again, all of these symptoms only happen when everything is hot going down the highway.

4. The slowing down takes place immediately after the pulling.

Interestingly enough, if I pull off the high and roam about on regular streets immediately after experiencing the above, there is no problem. It does not even give a hint there was a problem.

I am thinking transmission/transfer case fluids needs to be changed.

Any thoughts from others with similar issues?

Thanks.

tStar

Could be a few things, My first guess would be the hub could also be a axle cv joint or bad u joints. The winning sounds like the front differential but could be the transmission or transfer case. Check the fluid levels in the diff, trans and transfer case. Next jack up the right side first and check if you can hear any distortion when turning the wheel. Then take the tire off and check the brakes could have a sticking caliper if every thing checks out the do the same to the left side. Just will take checking and elimination.

Thanks for the advice Cam7.

Here is what has been done so far:

1. Front wheel Bearings/Calipers/Pads/Rotors are all new.
2. Front Diff bearings (all 4) inclding seals are new with fresh oil.
3. Rear Diff drive-shaft seal is also new (last month), however, I topped up the diff (because it was low) with Lucas heavy duty oil stabilizer.

This just came to mind - Should I have used some kind of diff additive for both front and back?

Also, I was reading some of the other threads ?? on transmissions/Transfer cases and it sounds like the oil there may be responsible for some of the beahviours my Jeep is having. Any thoughts on this?

I suppose it really is a case of elimination. But it is starting to get expensive.

Thanks again Cam7.


Could be a few things, My first guess would be the hub could also be a axle cv joint or bad u joints. The winning sounds like the front differential but could be the transmission or transfer case. Check the fluid levels in the diff, trans and transfer case. Next jack up the right side first and check if you can hear any distortion when turning the wheel. Then take the tire off and check the brakes could have a sticking caliper if every thing checks out the do the same to the left side. Just will take checking and elimination.

well when you replaced the Gear Lube in the rear diff did you add the Mopar Friction Modifier, I have the same jeep but 94, and I am sure you have the limited slip rear diff and you need to add the Mopar Friction modifier, get it from the dealership for like $6.50


the limited slip friction modifier is only to be used in the rear differential.

i would start with fluids

well when you replaced the Gear Lube in the rear diff did you add the Mopar Friction Modifier, I have the same jeep but 94, and I am sure you have the limited slip rear diff and you need to add the Mopar Friction modifier, get it from the dealership for like $6.50


the limited slip friction modifier is only to be used in the rear differential.


I only added fluid in the rear diff and just topped up with Lucas.

I am not starting to lean towards fluids as the causes of my problems.

I will attend to the full drive line fluids and see if this makes a difference.

Thanks for you input.

well the Limited Slip Friction Modifier is required when fluid in the rear diff is changed.

lucas additive stabalizer is junk, imo. i would not use it. it will make the oil foam up and cause problems. either way, i would check t-case fluid level for the noise problem. that would be my first step. second would be check wheel bearings.

lucas additive stabalizer is junk, imo. i would not use it. it will make the oil foam up and cause problems. either way, i would check t-case fluid level for the noise problem. that would be my first step. second would be check wheel bearings.


Actually, the Lucas products has worked well for me in the past with other vehicles, so I won't run away from it just as yet.

As for the T/C, I will be changing that oil and the other drive line oils as well this week.

The wheel bearings on the other hand are all new up front and they do not appear to be giving any troubles.

Thanks for your thoughts.

tStar


When the noises start and then the pulling, check rotor tempuratures. You could have a brake hose problem.

Sometimes the lining of the hose comes loose and acts as a one way check valve. This keeps the expanding fluid in the caliper and the only way the expansion is alowed is to push the piston out.

I would start checking the side where it pulls toward first. The only fix then is to replace both front hoses and preferably the rear hose at the same time.

Not saying for sure but another idea to check out.

JD

Hey JDPacal,

Thanks for the note.

When the problem originally started a month or so ago, upon checking around with some local mechanics, these were the first thoughts which came to mind following my description.

That is what lead to the installation of new parts in the front end, hence, I am still having the same issues today.

From everything I have read recently on this forum of others having similiar issues, I am leaning towards fluid changes.

I have an appointment to have the fluids changed on Friday of this week.

If that does not work, I will re-check everything done including all the suggestions being offered.

Thanks again.

tStar

When the noises start and then the pulling, check rotor tempuratures. You could have a brake hose problem.

Sometimes the lining of the hose comes loose and acts as a one way check valve. This keeps the expanding fluid in the caliper and the only way the expansion is alowed is to push the piston out.

I would start checking the side where it pulls toward first. The only fix then is to replace both front hoses and preferably the rear hose at the same time.

Not saying for sure but another idea to check out.

JD