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DIY: manual transmission and rear differential fluid service
Yesterday morning, after 2 years/22k miles, I decided it was time to change out the driveline fluids considering they were still the original factory-fills. This was an easy task taking 2 hours start to finish including setup and cleanup. Both are straight forward drain & fill jobs. I'm terrible about taking pictures while wrenching, but I'll borrow a few from other threads to help illustrate the job.
To perform the job, I first backed up onto ramps, then lifted the front of the car with two jacks. In order to get the proper fill amounts in both the transmission and differential the car needs to remain fairly level. I use low-profile plastic ramps that were $30 from Autozone years ago, and two lightweight aluminum 1.5 ton jacks from Harbor Freight which are about $60-90/each depending on sale, coupon, etc. (http://www.harborfreight.com/15-ton-...ump-60569.html).
All 4 bolts (2 fill, 2 drain) directly accept a 3/8" drive ratchet head so no sockets or extensions are required. For the differential fill bolt you will NEED a ratchet with a flex head. I used this one, which worked well: http://www.harborfreight.com/38-in-d...het-62321.html
I first will always loosen and remove the FILL bolts before draining out the fluids. You will be draining a total of 7 quarts (almost 2 gallons) of fluid so make sure you have a large enough pan or waste container. After removing the bolts you will want to wipe them clean with a paper towel to help keep the new fluid from getting contaminated. The magnets on my bolts had very little material or sludge on them which is a great sign as to how the car is wearing in.
The transmission fill bolt is on the driver's side of the transmission housing, and the case is clearly marked FILL right next to the bolt. The drain bolt is on the passenger side and clearly marked DRAIN.
For transmission fluid I wanted a full synthetic fluid and went straight to Redline since their products have served me well over the past 15 years. Redline D4 ATF is the proper choice for our M7 transmission, and you will need almost the entire gallon jug (or 4 quarts):
The differential drain and fill bolts are both on the rearward side of the differential housing. The drain is easy to access, but the fill is a bit of a PITA (this is the toughest part of the job). As you can see in this picture, its tucked up in there a bit above the e-brake cable and swaybar:
You will need to buy 3 quarts of your preferred gear oil (base Stingrays will take 2.5 quarts and the Z51/Z06 will take just shy of the full 3). For the differential I stuck with the OEM fluid, which is ACDelco Dexron LS 75W-90 gear oil since it is known to contain the proper amount of anti-slip additive:
Finally got around to this today in my '15 Z51 A8. This was at 9,500 miles of street driving, no track time.
A flex head ratchet is a MUST. I used a 3" extension for the fill plug and a 10" extension for the drain plug.
Not sure if there is a difference between the A8/M7, but there are some heat exchanger lines with little radial fins by the drain plug that are a PITA to work around. No way to remove the plug without denting the fins slightly.
Overall it took me about 1.5 hours, mostly because I was pondering how to deal with the cooling lines. Eventually I just said F-it, and went after it. Turned out fine. Doing over could do in an hour or less.
Fill Plug access:
Drain plug access:
Here you can see how the extension dents the radial fins:
And the mess it makes... I used brake cleaner to clean up afterwards. And I'd remove the plastic air deflector next time...
Fill Plug:
Drain Plug:
Drain Plug:
This is the Plews pump from amazon and the GM LS oil. The pump got 99% of the oil from the bottles. I was impressed!
The car took nearly 3 full quarts right off the bat so there was no need. Had I not gotten all the fluid in, I would have gone for a short drive then removed the fill plug again to top it off.
Tranny and diff? If so, I'm guessing Amsoil ATF and Severe Gear 75W-90?
Man what a pita no room at all in getting the back bolts out of the trans pan. I put on a LG trans pan then also chg out the rear end stuff also. From start to end almost 4 1/2 hours and yes I used amsoil in the car.
These 2 jobs is a pain in the azz due to no room to getting to bolts at the rear of the trans pan bolts, then also cable's and stuff just in the way on getting to plug drains and getting the nuts back into place
03-27-2016, 03:12 PM
DIY: manual transmission and rear differential fluid service
Yes auto trans here, But also put the LG pan on it that holes more fluid to help keep the temp's down a little more.
