Next Question. Regarding Rear Diff:

[Cpt Marvel]

03 Liberty, Freedom Edition, Auto, 4x4, 3.7

Thing drives pretty well. 4x4 works in both ranges, though the "Part Time" light is on at "wrong time". I'll get to that issue, don't seem to be a big deal.

At times there is a good firm "thunk", either from the rear end or ******. Usually seems to happen on 1st to 2d shift or just prior to a complete stop. Talked to the previous owner and he said that it seemed to start doing that after he had the transmission flushed and service, though he wasn't real sure because it was his wifes vehicle. There also seems to be a low roaring from the rear end, guessing that could be because of the gearing in a 4 wheel drive.

The other day I was stopped at a stop sign on a rain slick road. Punched the gas and made a right turn. The right rear wheel spun until I let off the gas. Wondering if this is normal. Seems to me that it would be a limited slip type diff, and the left wheel should have kicked in. No? With that, the roaring and the "thunk", would it be worth it for me to pull the rear diff cover off and see if anything was amiss? Anybody clue me as to the specific diff it has back there?

Quickee: What are the best recommended spark plugs? I'd love to put iridium in it, only have to change those about every 100k miles.

 

[tjkj2002]

Wouldn't hurt to have the rear diff checked for to much slack between the ring gear and pinion.


Only use Copper core plugs(or the ones specified on the emission stickers under the hood on the radiator support).Change every 30k,takes 20mins to change the plugs in a 3.7.




DO NOT USE PLATINUM OR IRIDIUM PLUGS!!!!!!!!!!!!!!!




If you choose to not listen you still have to change the plugs every 30k and risk damaging the coils.See it all the time at work and those customers are not happy having to pay twice for 1 job.

 

[CactusJacked]

Weight transfer in a turn puts more vehicle weight on the outside tire, less on the inner. You have an open diff, and the inside rear tire slipping as it did was normal.
Check your rear upper control arm (boomerang). If badly worn, it can mess up your pinion angle, causing a driveshaft u-joint growl, as well as can make the rear go clunk. My worn one was doing both. With parking brake off and Jeep in gear (manual) or in park (automatic), rock the car forward and back and watch the control arm. If it's moving up and down at the rearend housing mount, it's time for a new one. Also inspect the two mounting points at the body and see if the bushings look shot.

 

[Cpt Marvel]

Wouldn't hurt to have the rear diff checked for to much slack between the ring gear and pinion.


Only use Copper core plugs(or the ones specified on the emission stickers under the hood on the radiator support).Change every 30k,takes 20mins to change the plugs in a 3.7.




DO NOT USE PLATINUM OR IRIDIUM PLUGS!!!!!!!!!!!!!!!




If you choose to not listen you still have to change the plugs every 30k and risk damaging the coils.See it all the time at work and those customers are not happy having to pay twice for 1 job.

And that's why I asked BEFORE doing the plugs! Thanks! I run the iridium in my Acura RSX. BUT that vehicle has a different purpose in life.

 

[Cpt Marvel]

Weight transfer in a turn puts more vehicle weight on the outside tire, less on the inner. You have an open diff, and the inside rear tire slipping as it did was normal.
Check your rear upper control arm (boomerang). If badly worn, it can mess up your pinion angle, causing a driveshaft u-joint growl, as well as can make the rear go clunk. My worn one was doing both. With parking brake off and Jeep in gear (manual) or in park (automatic), rock the car forward and back and watch the control arm. If it's moving up and down at the rearend housing mount, it's time for a new one. Also inspect the two mounting points at the body and see if the bushings look shot.

I'm getting a fair amount of movement at these bushings. Making the front of the diff go up and down

 

[TwoBobsKJ]

I'm getting a fair amount of movement at these bushings. Making the front of the diff go up and down

Those lower control arm bushings are common wear items too. Symptoms include jumping left or right on acceleration and the other direction when you let off the throttle.

Not a difficult replacement - can get new bushings pressed in at your local tire shop.

Bob

 

[Cpt Marvel]

Those lower control arm bushings are common wear items too. Symptoms include jumping left or right on acceleration and the other direction when you let off the throttle.

Not a difficult replacement - can get new bushings pressed in at your local tire shop.

Bob

Thanks Bob. I didn't actually FIND the upper arm this morning. Found it this afternoon while changing out the diff oil. On Jack stands so can't check it now unless I use a pry bar.

I got put that posi-trac additive in there?

 

[jeeptorino68]

There was some info on adjusting the rear cargo door because it sounded like a drive train clunk. Also a tsb for grand Cherokee with similar symptoms. My liberty does this too. Haven't figured it out yet