[MDSHARK81]

Hi Guys,
Time to fill up the M22 with fresh gear oil. Normally I use the oil school Valvoline Gl-4. 80-90 in white bottles. Someone recommended The new Valvoline Synchromesh. Anyone have any experience with this stuff in their M22 or M21 transmissions?? I called Valvoline and the tech help said it is rated as a GL-4 and “yellow metal friendly”???

[Daubert20]

That is referring to the brass synchro rings. Some oils have EP (extreme pressure) additives. These additives have sulfur (smells like rotten eggs) that attacks the copper in brass and bronze. They will ruin the synchros. Might be ok in your diff but not in an older trans with brass synchros.

[1968firebird455]

I have tried a couple different lubes in my M21 and I am running Brad Penn in it now and like it.

[MDSHARK81]

Thanks for the reply. It's getting hard to find Dino GL-4 gear lube. Who would figure? I’ve decided on Liqui Moly GEAR OIL: (GL4) SAE 85W-90. Had to mail order. Nothing local was GL-4, everything in stores was GL-5 Synthetic.

[Mr. G]

This is very interesting as I recently used Sta-Lube GL4 85w-90 in a rebuilt M-20. The lable states that it does have extreme pressure additives but will not corrode copper, brass or bronze. Now I don't know if it is OK or not.

[MDSHARK81]

The Sta Lube is good. Recommended by Muncie rebuilders, but apparently it is now discontinued.

[turbo69bird]

I always run moroso climbing gear lube. Ever seen this stuff climb gears? It’s in believable , it allows you to run a lower level when drag racing .

[Held for Ransom]

More confusion. Here is the 1973 Owners Manual on manual transmissions. I use GL-4 rated 80W-90 though.

[MDSHARK81]

The unfortunate truth is we are the small minority of people driving 50 or 60 year old cars (also have a 65 GTO). The lubricants today are all made with modern cars and EPA laws in mind, not our cars needs. It is very difficult to keep up with the changing formulas used in these oils. My hope is the aftermarket continues to provide alternatives safe for us to use. This has happened for engine oils. Hopefully the heavy weight gear oil will be next. It seems our cars, are going the way of the Dinosaurs (pun intended), and us along with them.

[Elarson]

Here's the gear oil from Richmond Gear that I'm using in my Super T-10 to avoid all of the concerns with brass synchro compatibility.

https://www.richmondgear.com/auto-pa...t%253Agear-oil

Eric

[Sirrotica]

Old 50-60 year old Muncie trick, (works in T-10s too), use the intended gear oil with 10% STP. This would make the muncies shift like butter, as long as the blocker rings/synchros, were in good condition. I have no idea if that suggestion is still on the container of the STP, but back then, STP also recommended using 10% in manual transmissions.

Hot Rod magazine back in the day recommended the STP additive for fresh rebuilds. I have done it on my own cars back then, and it worked very nicely, YMMV.

Link to the same inquiry on another forum:

https://www.gtoforum.com/threads/whi...-speed.133083/

[Held for Ransom]

Originally Posted by Elarson

Here's the gear oil from Richmond Gear that I'm using in my Super T-10 to avoid all of the concerns with brass synchro compatibility.

https://www.richmondgear.com/auto-pa...t%253Agear-oil

Eric

But that lube is for rear end gears, not transmissions.

[3X24SPD]

I use this in all my Muncie & B/W 4-speeds:

https://www.amsoil.com/p/amsoil-75w-...gear-lube-mtg/

[Elarson]

Originally Posted by Held for Ransom

But that lube is for rear end gears, not transmissions.

Click the link. It lists the recommended applications and it's their manual transmissions.

Eric

[Formulajones]

GL-4 stuff is still easily available here and what I use. Oreillys has a GL-4 brand that works well and the sta-bil that I also use is still available here. Napa always keeps it in stock on the shelf.

As far as synchromesh goes I don't think using it in a Muncie is a good idea. That stuff is much thinner and designed for newer modern 5 speed transmissions

[Held for Ransom]

Originally Posted by Elarson

Click the link. It lists the recommended applications and it's their manual transmissions.

Eric

I see that. But reading the bottle, there is no mention of transmissions. Unlike PennGrade 1.

[Sirrotica]

Synthetic oils are said to be too slippery, the lube needs to be sticky to slow the rotation of the synchronizers, and make them coast down, and line up quicker. This is the common fact that manual transmission rebuilders cite in the older style transmissions. You also need the extreme pressure additives in non synthetic lube to form an oil wedge between the moving parts. The clearances in the old 4 speed boxes, are likely much different than the newer manual transmissions. The EP lube is usually 80W-90 weight.

STP is known to be very sticky, like honey, hence the reason it would work well in slowing speeds, unlike synthetic that reduces friction causing the parts to coast down more slowly after the clutch is disengaged.

I've used the synchromesh lube in my 1988 Fiero with a Isuzu made 5 speed. GM also used a Getrag 5 speed that used the synchromesh fluid. The synchomesh fluid is a 5W-30 weight, so no where near thick enough for usage in a Muncie, T-10, or a super T-10.

[lugnutx2]

I use this, recommended by Paul Cangialosi from Super661. Driven Racing Oil GL-4 conventional gear oil is designed to deliver maximum performance and protection. The formula features proven oil technology to provide application-specific performance for gear boxes, transaxles, and transmissions that call for GL-4 gear oil. Utilizing high-quality base oils, Driven GL-4 protects yellow metals and offers proper synchronization to prevent gear clashing in synchronized manual transmissions.

[Elarson]

Originally Posted by Held for Ransom

I see that. But reading the bottle, there is no mention of transmissions. Unlike PennGrade 1.

Well, I have to admit that I was wrong (and the Richmond website that I linked is wrong).

I checked the bottles that I have on the shelf and it is the GL-4 version from Richmond and the bottle mentions manual transmissions, brass synchro rings, etc.

Apologies for posting incorrect info.

Eric

[Formulas]

Pretty much the brand does not matter .... The GL rating does matter... 4 is what the old school muncie likes