Transmission Fluid

[Michael M.]

For a 1979 Corvette, L-48, Auto; what is the correct Transmission Fluid to use and where can I get it? In addition, the transmission pan on my 3spd Auto is missing a bolt, where can I get a correct bolt for the pan, and is the gasket going to by poly, or cork, and what should I get for that too, because I'm going to be taking down the pan. Please advise?

[Edward J.]

Re: Transmission Fluid

Mike, Dexron trans fluid from Gm late models will still work its backwards compatible. I would use a cork gasket if you can get, maybe Gm has them??

[Michael M.]

Re: Transmission Fluid

Thank you Edward,

I'm hearing Dexron II, you wouldn't happen to know the torque specs on the TH350 trans pan bolts would you, or perhaps an NCRS manual that would provide that info?

[Terry M.]

Re: Transmission Fluid

Thank you Edward,

I'm hearing Dexron II, you wouldn't happen to know the torque specs on the TH350 trans pan bolts would you, or perhaps an NCRS manual that would provide that info?

If you intend to work on your Corvette yourself a Factory Service Manual will be helpful.

https://www.ncrs.org/shop/index.php?main_page=index&cPath=1_68&sort=20a&page=1

Unfortunately the NCRS Store only goes up to 1977, but you need the equivalent for 1979. That will give you the torque values for the transmission pan bolts. Here is one I found with a quick search:

https://www.ebay.com/itm/1979-Corvette-Shop-Manual-79-Repair-Service-Book-Chevrolet-Chevy/164017092609?_trkparms=aid%3D555021%26algo%3DPL.SIMRVI%26ao%3D1%26asc%3D20190711100440%26meid%3D2e241a9605e1446795165db894471439%26pid%3D100752%26rk%3D3%26rkt%3D8%26mehot%3Dpf%26sd%3D353065638695%26itm%3D164017092609%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplRVIAMLv5WebWithPLRVIOnTopCombiner&_trksid=p2047675.c100752.m1982

This is a reproduction, but my esperience with this vendor is that their reproductions are of good quality.

You will also want a 1979 Assembly Information Manual (we refer to these as an AIM):

https://www.ncrs.org/shop/index.php?main_page=product_info&cPath=78_1&products_id=224

The 1978-79 Technical Manual & Judging Guide will tell you what NCRS judges; and a Judging Reference Manual will tell you how we judge Corvettes. Over time you can build a library of information needed to support your Corvette.

[Michael M.]

Re: Transmission Fluid

Thank you Terry.

Let the reading begin!

Michael

[Richard G.]

Re: Transmission Fluid

12-13 foot pounds for the pan bolt. I use 150 inch pounds.
Personally I don't like the cork gaskets.
I prefer the black ones. You can't fold them but they work much better.
Try cobratransmission.com. They may be close to you?
The cork gaskets are $1.99 (Part #: 44300) and the fiber ones are $4.99 (Part #: 44300F)


Don't use any silicone products on the gasket surfaces.
Install the pan gasket dry. Clean the transmission and the pan with a de-greaser and install.
If you need one or two bolts PM me, I will send you what you need as I have extras.
Rick

[Edward J.]

Re: Transmission Fluid

What ever gasket you choose make sure the punched holes for the bolt is a fight fit they sometimes make them to big and this a leak problem.

[Joe L.]

Re: Transmission Fluid

For a 1979 Corvette, L-48, Auto; what is the correct Transmission Fluid to use and where can I get it? In addition, the transmission pan on my 3spd Auto is missing a bolt, where can I get a correct bolt for the pan, and is the gasket going to by poly, or cork, and what should I get for that too, because I'm going to be taking down the pan. Please advise?

Michael------


Use transmission fluid Dexron VI. You can get this just about anywhere that automotive parts are sold and in a variety of brands. The GM/ACDelco fluid is GM #88865549, aka Delco 10-9243 and available at any GM or AC Delco dealer.

As far as the gasket goes, I recommend using a rubberized cork with steel insert. You can obtain this under Mahle # W39348TC. DO NOT OVERTORQUE the pan bolts.

As far as the pan bolts go, if you want original configuration, your best bet is to get them off another transmission. Otherwise, simply match the thread size and length with your existing bolts and add a washer, as necessary.

[Michael M.]

Re: Transmission Fluid

Thank you Rick.

Once I take it down. I'll be able to do more and follow up on your leads.

Thank you for the help.

Michael

[Michael M.]

Re: Transmission Fluid

Joe,

The owner's manual requires Dexron II, and you're suggesting Dexron VI, please explain to me the difference, and how it could affect my transmission? Not knowing how it affects the transmission and why one is different from the other, is what stopped me from going out and just buying one of the modern Dexrons on the market.

Mike

[Joe L.]

Re: Transmission Fluid

Joe,

The owner's manual requires Dexron II, and you're suggesting Dexron VI, please explain to me the difference, and how it could affect my transmission? Not knowing how it affects the transmission and why one is different from the other, is what stopped me from going out and just buying one of the modern Dexrons on the market.

Mike

Mike-------


The only way you're going to be able to use Dexron II, GM #1051855, is if you find some old stock. It was discontinued by GM in October, 1994. I know of no other manufacturers that offer this transmission fluid as GM ceased licensing it about the time it was discontinued.

Dexron II was replaced by Dexron III which was later replaced by Dexron VI (there was no IV or V that I am aware of).

Dexron VI is a vast improvement over Dexron II and all earlier Dexron formulations. GM recommends it for all transmissions originally specifying earlier Dexron formulations. If I had a transmission originally specifying an older version of Dexron AND if I had a massive supply of that older fluid I would not even consider using it

[Michael M.]

Re: Transmission Fluid

Joe-----

Thank you. Yes, I see plenty of vintage cans of Dexron II on Ebay for sale; I don't want 40 year old fluid either. But I wasn't sure if it was something that was still available, desirable, needed, etc. If the Dexron VI is what we're all using now, and it doesn't need an additive or some other treatment to not do damage to our transmissions; then that's the information I was searching for.

Thank you,

Michael

[Richard G.]

Re: Transmission Fluid

The lubrication has changed a bunch because of what we now know.
The modern oils (Dexron)are backwards compatible and a much better product than that of old.
Use the current available products with confidence.

[Michael M.]

Re: Transmission Fluid

Thank you Richard.

[Patrick H.]

Re: Transmission Fluid

The cheapest place I find for Dexron is Amazon.
I buy it in the 1 gallon containers.