Prime1

Hello to all, I am changing the fluid on my 4 speed manual trans and need to know the location of the drain and fill plug. Is it on the drivers side or passenger side? All I can find on the internet is pictures for the automatic trans. Here are my corvette specs.

1972 - LT1 convertible
4-speed manual trans

Thanks

Bikespace

In my 80's B&W Super T-10, the plugs are on the passenger side, away from the shift linkages. Muncies are the same. If you are lifting the car in a way that the side will matter, you probably won't get the level correct when you refill. Race Ramps in front, jackstands in the rear, and you can get the car elevated and level.

Pro-tip: Take out the top plug first. If you can't get it out, at least you haven't emptied the transmission and stranded the car.

resdoggie

Buy a cheap oil suction gun to refill the transmission.

4-vettes

or a cheap, if not free squeeze bottle with a foot of tubing on it. And DO NOT be tempted to put in any kind of synthetic trans lube. the old synchro's won't like it at all. stick with dyno oil.

Bikespace

I use a cheap transfer pump. You can get pumps that screw into your gallon of gear oil. The giant turkey-baster type is helpful for the differential, that does not have a drain plug (unless a PO put one in).

I use GL-4 synthetic. YMMV, there are lots of threads to read on that subject.

stingr69

I used a 4 ft length of rubber hose from the hardware store with a funnel at the top. Fill while standing next to open hood. Keep drain pan under tranny in case you over fill a bit.

ralphspears

It might not have a drain plug

4-vettes

May or may not be a ton of threads on the topic. Although I have read a few. most agree. Do NOT put synthetic gear oil in these old transmissions.
I tried it. Super horrible results. drained it out. put in a standard mineral based gear oil. shifting perfectly again.
Synthetic gear oil's are to slippery for these old transmissions. They were not designed for it. Period.

toylman

Fill and drain plugs are on the right (passenger) side. Use GL-4 Conventional oil. This is the one that best suits older manual transmissions with "yellow" metal parts. Read what 4-vettes says.

Hopper12

This extractor makes easy work of getting the old stuff out, and putting the new stuff in. Use it to suck the old oil out, clean it out a bit, and use it to suck the new oil out of the bottle and into the trans - a few refills in this with the new oil and you're done when it begins to dribble out of the fill plug. I drive it a bit and recheck because it usually will take another bit to top it off after driving. Not all that expensive for making the job much easier - and I think it's very likely you don't have a drain plug. Have fun, Paul
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Prime1

thanks for the pics. I think the exhaust pipe was blocking my view.

Prime1

Thanks for all the tips guys!
1972 LT-1

toylman

All C3 owners love LT1s. Here's my recently purchased 1970.

Sigforty

Passenger side the high plug is the fill and low is the drain.

F4Gary

Seriously?

ED DINAPOLI

On the lower unit of an outboard motor, you fill from the bottom. So it could be important to understand the proper procedure.
Ed

Prime1

What is the best way to get that square head fill plug out? I tried a 9/16 wrench and it keeps slipping off, and so does a crescent wrench, and it is too tight with the exhaust in the way I cannot get a socket in there.

Thanks

Bikespace

12-point ratcheting wrench, perhaps?

Take a picture. How close is your exhaust? How to you plan to refill the transmission if you don't even have room for a socket?

MelWff

I use 8 point sockets on transmission and differential

stingr69

19/32" open end wrench.