Rear-Diff fluid change questions
Thread Starter
Le Mans Master
Joined: Jan 2004
Posts: 7,276
Likes: 3
From: Why are there squished peanut butter cups in my underware?
Rear-Diff fluid change questions
For my `91 6-speed, D44 rear differential.
1) For the plug, which type of wrench do I need and what size?
2) For the replacement fliud, GL-5 80w-90 is in the book. Any real world recomendations?
3) What type of Posi-additative should I use?
Thanks
1) For the plug, which type of wrench do I need and what size?
2) For the replacement fliud, GL-5 80w-90 is in the book. Any real world recomendations?
3) What type of Posi-additative should I use?
Thanks
Le Mans Master
Joined: Aug 2002
Posts: 6,080
Likes: 3
From: Clearwater FL
St. Jude Donor '06
There is no plug unless one has been added. You either have to split it apart or insert a tube into the fill plug and draw it out. You need the GM diff additive (2 bottles I think) unless you are using synthetics which have the additive package in it. There is debate over weather the additives are enough or if the GM additive still needs to be added.
I recently had my gears converted to 3.91, and had a drain plug installed. When I change the fluid at 1000 miles, I've decided to go with Amsoil severe duty which has extra additive in it for the LSD. Forum member subdriver sells it here. There are many threads in the archives on this subject too.
BTW, Royal Purple and Mobile also make synthitic gear lubes for it.
I recently had my gears converted to 3.91, and had a drain plug installed. When I change the fluid at 1000 miles, I've decided to go with Amsoil severe duty which has extra additive in it for the LSD. Forum member subdriver sells it here. There are many threads in the archives on this subject too.
BTW, Royal Purple and Mobile also make synthitic gear lubes for it.
Le Mans Master
Joined: Sep 2003
Posts: 5,874
Likes: 0
From: Littleton CO
Originally Posted by Z-07 freak
For my `91 6-speed, D44 rear differential.
1) For the plug, which type of wrench do I need and what size?
2) For the replacement fliud, GL-5 80w-90 is in the book. Any real world recomendations?
3) What type of Posi-additative should I use?
Thanks
1) For the plug, which type of wrench do I need and what size?
2) For the replacement fliud, GL-5 80w-90 is in the book. Any real world recomendations?
3) What type of Posi-additative should I use?
Thanks
2) I used the GM fluid. So far, so good.
3) I used the GM additive; two bottles seems to be recommended according to most. If noone beats me to it, I'll look up the part number once I get home later.
I bought the fluids over at Luby Chevrolet. Prices seemed reasonable enough, so I didn't shop around.
Last edited by jrp; Aug 4, 2006 at 05:01 PM.
Le Mans Master
Joined: Feb 1999
Posts: 9,919
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
GM part number is 1052358 for additive.
Some Synthetic fluids dont require the additive. Redline, Amsoil, Royal Purple, and Mobil 1 ( I believe, still researching)
Some Synthetic fluids dont require the additive. Redline, Amsoil, Royal Purple, and Mobil 1 ( I believe, still researching)
Drifting
Joined: Sep 2003
Posts: 1,483
Likes: 4
From: middle TN
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Team Owner
Joined: May 2002
Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by Z-07 freak
What about 80w-90 vs. 85w-140?
That will cost you horsepower and fuel economy running the 140. I wouldn't use anything thicker than I had to. I'm running Valvoline non-syn 80w90 (or is it 75w90) same difference.
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
If you decide to go to a synthetic oil from a conventional oil, you *may* find a new leak under the car in a short while. My 90 did this to me. Its a bit of a pain to replace the seals and it will also lead to many "while-I'm-in-here" repairs - for me it was new poly bushings and u-joints. Oil leaking on the OE rubber bushings will destroy them over time.
Just food for thought...
Just food for thought...
Le Mans Master
Joined: Oct 2003
Posts: 7,625
Likes: 4
From: Director of Bands
St. Jude Donor '08
Originally Posted by Scooter 94
I used this stuff. In stock at my local Autozone.
Trans-x limited slip additive
Trans-x limited slip additive
