Fluid for Muncie 4 speed

[poison heart]

As I was putting my tranny in the other day I remembered that it didn't have any fluid in it. It's a 1970 Muncie M20 What is the best stuff to put in it? Do I have to drop it or can I use the drain plug to fill it? How much do I put in?

[DaWildcat]

This is an "it depends" situation. Early Muncies only have a fill plug, so you have to find a way to evacuate the old fluid if you want to replace it. You ten fill from the same plug until the fluid is level with the bottom of the plug hole. If you're lucky and have a later trans, it will have both a fill and drain plug making life easier.

http://www.5speeds.com/P0001763.JPG

80W-90 lube is popular, you'll need around 1.5 quarts.

Devon

[PaulGS]

You need a GL-4 lubricant.

I use Amsoil Severe Gear 75w-90 sythetic in my M21/

It shifts like butter......

[poison heart]

There is no fluid in it right now. It was drained out when the guy shipped it to me. I'll fill her up then. I'll look into Amsoil.

[DaWildcat]

There is no fluid in it right now. It was drained out when the guy shipped it to me.

Sorry, I read that in your first post...and promptly forgot it!

Devon

[David Hemker]

I suggest staying away from synthetics. I tried it twice and broke the trannys within a very short time. Went back to standard grade oils and have had no problems since.

[SS-TRUCK]

If you are going to use the trans in a high RPM motor I would use a gear oil as close to 75 wt as possible , but as an every day driver the 90wt would be fine .

[poison heart]

I don't plan on reving this thing over 6000. It's not a daily driver either. Just a cruiser street car. It'll have some balls though.

[SS-TRUCK]

Robert if you can find the 75-90 gear oil you should be fine . good Luck .

[PaulGS]

The GL-4 requirement is important. It protects the brass parts in the tranny.

[Horsman]

You need a GL-4 lubricant.

I use Amsoil Severe Gear 75w-90 sythetic in my M21/

It shifts like butter......

Will the GL-5 fluid be ok also?

[DaWildcat]

The GL-5 has the additives that are hard on the brass parts.

Devon

[poison heart]

I put valvoline 80-90 in it. I got maybe 1.25 quarts in it. It's right below the fill plug. I guess that's as much as it takes? I guess there could have been a little left in it when it was previously drained.

[DaWildcat]

Sounds like you're good to go.

Devon