Differential Maintenance

[remoblades]

I have been feeling a pull each time I attempt a U-turn or make a turn which requires the steering wheel to be turned fully.Anyone have experience with differential maintenance? How often should the fluid be changed? How can one tell if the problem is the front, center, or rear differential?

[JDPascal]

remoblades

What you describe would seem to be what I call wheel fight. You probably have the quadratrac - right?

A small amount is not a great concern but as it worsens it may cause other porblems. The cause is the infamous viscous coupler in the transfer case.

The fluid in it is supposed to thicken when there is wheel slip and speed difference between the front and rear axles. When the VC fails, the fluid thickens more easily and may stay in that state eventually. that makes it into 4wd all the time instead of ondemand.

the coupler can be changed on some models anyway without removing the transfer case.

The diffs and TC should have the fluids chaned atleast every two years to give the best service. No a huge expense considering the consequences. I recommend using a synthetic in all three locations as they reduce operating tempuratures.

JD

[remoblades]

Not sure if it's the same thing as quadra trac but I have 4 wheel drive all the time. Not sure if it has anything to do with transfer case.

[JDPascal]

Originally Posted by remoblades

Not sure if it's the same thing as quadra trac but I have 4 wheel drive all the time. Not sure if it has anything to do with transfer case.

all the time 4wd in a jeep is called quadratrac. It has everything to do with the transfer case.

It is really supposed to be 4wd on demand. the viscous coupler is supposed to allow no power to the front under normal on road conditions. only when there is a speed difference betweeen the front and rear axles ( slippage) does the viscous fluid heat up and provide the drive to the front axle.

what you describe is a failing or failed VC in the transfer case.

JD

[remoblades]

You are the man JD. Thanks for the lesson. I was offered a price of $30 to replace the fluid in my rear differential alone. Is this reasonable?

[JDPascal]

Synthetic diff oil is about 8 bucks a qt (usd) going to need 2 plus .5 hour labor to be generous....yup 30 would be in the ball park.

I do my own. I use a small pump that I bought for the lower unit on my outboard motor. It screws right on to the dif oil container and I just pump it in with out the mess of trying to pour it in or use a suction gun.

Need some silicone (RTV) - 1/8" bead around the cover and tighten the bolts to 25 ftlb torque.

With the transfer case, some on here have changed out the quadratrac for a selectrac. There are a couple of threads on here that are good.

JD

[a_alyte]

When switching to synthetic oil in the Diffs & T-Case, should I flush before making the change? If so, what is the procedure?

I plan to use a pump to remove the old diff fluid but will take the covers off if necessary!

[jeeper61]

Flushing is good to keep the old dirt out of the new oil. all you need to do to flush is rinse down the inside of the differential housing with solvent once most of the oil has drained out. wipe the bottom of the housing with a clean rag and use more solvent and wipe again to get most of the junk that has settled on the bottom. that will make sure that it doesn't get picked up in the new oil and put thru the gears.

I read someware on here to run some new cheep oil for awhile to clean it up even more and drain that after a few miles and then put the synthetic oil in

[CTCarpenter]

Originally Posted by a_alyte

When switching to synthetic oil in the Diffs & T-Case, should I flush before making the change? If so, what is the procedure?

I was at the Jeep "stealership" to buy synthetic differential fluid along with the limited slip additive, and asked how they handle this type of switch. I was advised to use brake cleaner and wipe everything clean before re-assembly (especially at the bottom of the case).
I followed these instructions and everything went very smoothly, except refilling the rear differential which was difficult because of the fuel tank placement in front of the differntial cover. I used a section of 1/2" clear hose attached to the end of the gear oil bottle with a small hose clamp to squeeze the fluid in there.

[a_alyte]

That's intersting, I read on www.getahelmet.com that you could also use Kerosene to clean inside the Diff housing. The article also mentioned using brake or carburetor cleaner, but states that Kerosene is less harsh! The article goes on to say that Kerosene when used to degrease the gears, acts like a lubricant & will not break down the rubber seals like solvents do.

My only queston now is about the T-Case. When switching to Synthetic is it a big job to remove the T-Case cover, or is it just like removing the diff covers?

[CTCarpenter]

Originally Posted by a_alyte

That's intersting, I read on www.getahelmet.com that you could also use Kerosene to clean inside the Diff housing. The article also mentioned using brake or carburetor cleaner, but states that Kerosene is less harsh! The article goes on to say that Kerosene when used to degrease the gears, acts like a lubricant & will not break down the rubber seals like solvents do.

My only queston now is about the T-Case. When switching to Synthetic is it a big job to remove the T-Case cover, or is it just like removing the diff covers?

I wonder how you'd get the kerosene into the differential case? The Brake cleaner comes out in a nice forceful stream, washes out the gunk and the disapates quickly.

The gear oil for differentials is Mopar Synthetic Gear and Lubricant Sae 75w-140, don't forget the Mopar limited slip additive. The fluid for the tyansfer case is ATF+3 Type 7176 Automatic transmission fluid (it is not synthetic to my knowledge).
The transfer case fluid is drained from the 1-1/8" drainplug near the bottom rear of the t case and filled with another 1-1/8" plug about 6" higher from the drain plug after you replace the bottom plug.

Hope this helps...I'm new to this also.

[a_alyte]

I believe the article said it was best to put the kerosene in a spray bottle & go from there.

I was considering Mobile 1 synthetic for my T-Case. I know about the drain & fill plug, but I was wondering if removing the T-Case cover is as simple as removing the diff covers, or is there more to be aware of.

I'm asking about the T-Case cover because I would like to really clean the T-Case gears before switching to synthetic (if its not too much work), instead of simply using the drain plug!

As long as we all keep communicating ideas & knowledge, I think we'll be alright!

[JDPascal]

The opening of the t-case is not a small job. you need to remove the t-case from the vehicle then the case splits in half to acess the chain and shafts. then it has to be resealed again to go back together and then reinstalled. You would lose most of the atf in the transmission in the process.


To change the oil all that is required is the removal of the drain plug. It is a large plug on the back side of the t-case at the bottom. I think you will need a 1 1/8 wrench to fit. The fill plug is right above it.

Mobil 1 ATF is an excelent choice for the refill.

The transfer case isn't open to the dirt like the diff - most of the time. If you like you can change it again in a couple of months to make sure you have more of the bad stuff out.

JD

edditedd because of a brook spelling finger

[a_alyte]

Thanks JD, I had a feeling that the T-Case would entail more work than the diffs. I'll stick to using the drain plug when switching the T-Case to synthetic.

Af far as a new rad goes, does anyone have any suggestions as far as sticking to the OEM? Any quality aftermarket rads being used?

[JDPascal]

dksob81 mentioned 'radiator express' as where he got a rad for his 94 5.2. I think he said it was $175 vs $300 from the local rad shop.

if you google it should find it there.

JD