The Stovebolt Site Forums The Shop Area Engine Shop 1951 Chevrolet transmission leaks

Hi guys,
I have the original 4-speed transmission in my 1951 Chevrolet 3604 pickup. The transmission leaks slightly on the rear end pumpkin gasket, and the actual transmission side plates. I know they need to be replaced but I would like to check the transmission level to see if I am low. I want to have everything ready to go when I put it in storage this winter, I also start her up once a week in storage as well. How does one check the fluid level on these transmissions? If I replace the pumpkin gasket, how do I fill up the rear end and how much? Every detail you can give me would be greatly appreciated.

You have a drain plug on the very bottom underneath the driveshaft enclosure. If you are going to drain it that is the time to do the side gaskets. If it has never been drained there we be some nasty sludge in the bottom you may want to flush it w/kerosene once the side plates are off. You refill through a plug about 1/2 way up on the passenger side this is also the level control, when it trickles out of the open hole you have it filled. As I remember it was two quarts and then some from a third after a complete drain. If you use the bottles with the top that can be cut for flow you can angle that into the hole to help fill. Pull the trans cover inside the cab and it is a bit easier.

I filled mine up to the hole and it leaked out the front cover. I then read the manual and it is only supposed to be up to the hole when it is warm. The proper cold level is 1/2" below the hole.

Now I never seed that in the manual Fred, I'm gonna have to check it out. I've always topped them off till the fluid ran out the side plug. Even after all the work I did on the closed drive shaft portion of my 3/4 ton I still get a LOT of oil puking out the rear seal right in front of the u-joint.
I don't have any problem with leaking out the front, just the back end.
Denny Graham
Sandwich, IL

Thanks you guys. As soon as I get some new gaskets, I am going to give it a go. Any suggestions on a specific brand of transmission oil to use or NOT to use? Thanks again, Jeff.

Probably several opinions on what is best, brands like Redline and LE oils can run as high as $15 dollars a quart and they are really good or you can go to the local discount auto and buy Castrol/Quaker State etc. for $3 dollars a quart. See if anyone else chimes in. Cost, quality, volume of potential leaks in the future may determine what you want to use. I used a brand called Lucas which was sort of mid-point priced $6 I think. I figured since I probably won't change it that often I would use something heavy duty and I had used their products before.

Thanks for the suggestions Brad.

Denny,
have a look at page 0-5, top right paragraph of the shop manual. That is where I saw the 1/2" method. Also, the problem with a leak out the front is that it can run down into the clutch itself.

Fred

Yep thar it is, thks Fred.
Denny G