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):
http://www.mitsustyle.com/photopost/...1019152102.jpg


I used this pump from Harbor Freight which screwed directly onto the gallon jug and worked perfectly: http://www.harborfreight.com/gear-oi...ump-61746.html

Amazon sells one that appears identical here:

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:
https://cimg8.ibsrv.net/gimg/www.cor...dd7cb2957c.jpg


Here is the factory service manual guide:
Attachment 48363415
Attachment 48363416

The above picture and illustrations have graciously been borrowed from Theta's How-To thread located here: https://www.corvetteforum.com/forums...ice-specs.html

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:
http://www.mitsustyle.com/photopost/...1015152217.jpg


To fill the differential I used this pump, which screwed directly into the quart bottles and worked as intended:

If there is anything I missed, please just ask and I will do my best to answer and get it added to my post!

Awesome write up, thanks for taking the time to do this!

You're welcome. If I feel like being productive later this week I'll jack the car up again and take pictures of the transmission plugs.

Nice, very thorough... Like the links to the tools you used. Thanks dude.

:thumbs:

Thank you, just trying to help out where I can!

Kracka are you in a z51?

Yes sir!

Thanks! So how did you do that last step where it says to start the car and accelerate to 10 mph while the car is still lifted?

I was thinking about doing this before I leave Thursday for the Texas Mile but might do it after.

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.

Ahh ok gotcha. Filling it looks like a pita! Is it that hard?

Snaking the pump's hose up there is easy. The tricky part is the fill bolt, but by no means impossible as long as you have the flex-head ratchet.

Thanks! Did you need the flex head ratchet for the differential or just the transmission?

The only one of the four plugs that needs the flex-head ratchet is the differential fill bolt.

ttt
 

Nice write up man I will be doing mine in my car this coming tues when I am off. But I will be using AMSOIL in mine.

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:lol::lol::lol:

Sounds like you did an automatic transmission service, luckily, the manual transmission is far easier!

For guys wanting to use Redline fluids:
M7 = D4 ATF
A6/8 = D6 ATF

:thumbs: 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.

Am I reading your post correctly? You said you drained almost 7 quarts but only filled 4 quarts?

Edit: Nevermind. You're referring to both jobs.

Correct :)
4 quarts in the transmission and 3 in the differential.