DIY: Gen 4 Front and Rear Differential Oil Change

[AltaBrig]

I changed my rear differential fluid yesterday at 35K miles and decided to post this to help anyone else do this super easy DIY. I will be changing it on a shorter interval going forward. The old oil was silvery black and there was quite a bit of metal stuck to the drain plug magnet.

Tools and oil:

Breaker Bar
Torque Wrench (36lb/ft is what I used)
13mm Hex Bit (for the fill and drain plugs)
Measured Receptacle (if you want to know how much fluid was in the case)
Gloves and Rag
75w90 GL-5 0.8 Quart (25.6 oz)



Loosen the fill plug first or the drain plug may seize.



Place receptacle below drain hole while loosening drain plug.



Clean off magnet in the drain plug.



My oil was not honey colored. Seemed about .8 quart on the nose.



Replace the Drain Plug and torque at 36lb/ft.



You can get 25.6 oz out of the quart bottle with a couple of squeezes. It is not necessary for this job, but there are hand pumps and tubes available at the auto parts stores to make it easier. Fill her up to the bottom of the fill plug.



Replace the fill plug and your done.



Money saved and confidence in a job done right.

[1 Lucky Texan]

cool - interesting how the newer diffs look.

[AltaBrig]

Changed my Front Differential fluid at 35K yesterday and decided to post this simple DIY fluid change and washer replacement.

Washer and Fluid:
New Black Washer for Drain Plug (Part #803926090)
1.5 quart (48 oz) 75w90 GL-5 Gear Oil



Tools Needed:
Breaker Bar
Torque Wrench (51.6lb/Ft)
T-70 Torx (Star) Bit
Measured Receptacle (if you want to know how much fluid was in the case)
Rag and Gloves



Receptacle under plug before loosening with breaker bar.



Loosen then remove quickly by hand.



Drain out 1.5 quarts of old oil (mine is as filthy as my rear diff fluid was -chocolate not honey colored.)



Don't forget to put the new black washer on the drain plug.



Torque/tighten the drain plug to 51.6 lb/ft.



1.5 quarts and an old washer.



Fill the Front Differential case with 1.5 quarts or 75w90 oil via the front transfer dipstick tube. Try not to spill like a little like I did. I had to use two funnels to navigate the engine compartment. A long Rhino Super Funnel should work better for the application.



Check the plug. Check the dipstick. Take it for a quick spin. Check the level and the plug again. Done with money saved and confidence in a job done right.

I am going on the 15k interval after that mess poured out. Maybe unneccessary, but it is cheap and easy preventative maintenance.

[Ticmxman]

Excellent DIY! What does the dealer charge for this service?

[AltaBrig]

Originally Posted by Ticmxman

Excellent DIY! What does the dealer charge for this service?

Sorry for the blurry pics.

Local subie mechanic charges $45-50 each for the Front and Rear (not bad, but not synthetic gear oil either). Dealership combines the front with the 4 quart ATF drain and fill service for $180. Dealer charges $55 for the rear.

[rockhopjohn]

So I merged your two DIY threads into the first one which had been moved to the DIY sub-forum. Thanks for a great DIY.

[Cobalt]

Nice write up and the pics should put first timers mind at ease, we that grew up doing this stuff with Dad too often forget that many didn't get that opportunity.

[AltaBrig]

I was lucky enough to have a few friends who worked on cars. Their knowledge gave me the confidence to do the easy things like fluids, shocks, brakes, 02 sensors, and fuel pumps. Car shows are pretty good, YOU Tube has a wealth of DIY videos, and sites like this one give first timers like me on this OB a bit of confidence. I only have the confidence to do the easy routine maintenance. I helped a friend replace some heads once, and I don't want to ever have to do that with the H6.

Thanks for combining the threads RockHopJohn. I didn't want to try to post it all at once for fear of losing it. I closed my window when I was almost done with the first thread and had to start over.

[NickH]

Nice post! Much appreciated.

Nick

[mws4ua]

Forgive the Soob noob question... Are the front and rear differentials in the 2.5i the same as the 3.6R? I suspect they are, but don't want to assume and screw something up.

Great write-up, btw. Thanks!