Transmission Fluid - Which To Use?

[bigboi]

I have a Muncie 4psd and I am currently using Amsoil in it. I notice when the tranny is cold the gears shift fairly easily. But after I drive the car around for a while shifting gears feels a little more sticky.

Is this normal for these transmissions? I am using Amsoil which I heard was good fluid to use.



Your thoughts?

[crash]

I build a lot of Muncie's, Borg-Warner T-10's and ST-10's and Nash/Richmond 5&6 speeds...
I tell my customers if they use synthetic gear lube it VOIDS the warranty...

Synthetic gear lubes are tooo slippery for the brass/bronze blocker rings to do their job...

You should only use GL-4 petroleum base gear lube...

Also if you look at GL-5 petroleum base gear lube and it says its ok to use in posi-trac rear ends,
it will have a friction modifier that is not good for the blocker ring either... Crash

[H8tulooze]

What are you using 85/90w?

[crash]

Pennzoil Gearplus GL-4 80-90... Crash

[chicane67]

Crash nailed the synthetic issues with the available late model 'brass-alloy' sync's that are available in the typical rebuild kits. I will not recommend any synthetic lube in a Sag, Muncie, T-10 derivative or top loader.

I myself only use a parrifin based straight weight 90 with a suspended moly... for that peticular application.

[bigboi]

Yes 85/90. I think I should probably switch to the Penzoil crash is referring to. Thanks!

What are you using 85/90w?

[bigboi]

Where can I get GL-4? I can't seem to find it.

Pennzoil Gearplus GL-4 80-90... Crash

[crash]

I friend of mine owns a speed shop and buys from a Pennzoil Distributor 25 cases of 20-50 racing oil at a time and when I need gear lube I order 3or4 5gal buckets with him and get free shipping... Crash

[Blown353]

Where can I get GL-4? I can't seem to find it.

If all else fails your local GM dealership should have GL4 bottles in stock-- mine does.

The higher sulfur content in the GL-5 additive package, as mentioned, isn't beneficial to the longevity of the syncros.

[TnBlkC230WZ]

GL4 and GL5 non-synthetic is pretty common at most parts stores. I use Valvoline non-synthetic. I think it is GL-5 with no problems.

I wonder if Royal Purple will work in these?

[Rick Dorion]

I had used Redline synth in my Autogear and it was notchy; switched to Amsoil GL-4 and it was much better. After reading this I went to NAPA and bought GL-4 StaLube and it is even smoother shifting. Good thread!

[flynbrian]

I have a autogear M21Y and it shifts like crap going into 2nd gear...I am not really happy at all with this tranny. I called and talked to George and he said to run MT-1 spec gear oil..."Cheap stuff" as he called it So I bought Valvoline gear oil MT-1 spec....

I am about to try TORCO RTF Racing Trans Fluid...Its real thin and wont affect the synchro's....I talked to Torco for like a hour about it on the phone. They felt my Valvoline gear oil was too thick/slick and not letting the synchro's work right.
If I shift like grandma at low RPM its fine....If I shift like Grandma at high RPM....It grinds like MAD! IF I shift it real hard and firm at high rpm it seems to be OK.
The Tranny is brand new with about 2000+ miles on it of cruising around... I'm pretty mad about the way it shifts. My buddys all like the feel of the crisp detents and racey feel...But I wont let them drive my car to see how bad it really feels.
It sounds god awful at times...If the fluid doesnt fix the issue then I will have to have the tranny torn down and repaired. I will have to cross my fingers....Cause this thing has felt bad since day one...I cant afford to be shipping it back to New York either...Or I would have told them to stick the thing you know where...And went out and bought a 5 speed overdrive instead.