Transmission oil recommendations?

[Guest 36chev]

There have been several threads cautioning about the use of EP (extreme pressure) gear oils in transmissions or differentials with bronze or other yellow metal parts. The concensus appears to be not to use GL 5 rated oils because it contains the EP (sulfur?) components which erode yellow metal. GL 4 is supposed to be ok.

The local auto parts places have indicated that their 80/120 oil (which is the basic weight range recommended for use in the 36 Chevrolet) is rated at a combined GL4/GL5. They do not have a separate GL 4 or GL 5. It doesn't give any listing of additives. The 36 has bronze bushings in the transmission.

What would be a readily available gear oil (85 or so up to 120 weight, multigrade ok) safe to use on a transmission with bronze bushings? It would be good if auto parts stores would have or be able to order rather than mail order. The same oil will also be used in the differential. Thanks!

[unimogjohn]

This is what I use. Will not erode yellow metal and gives you long life. I am not a dealer, just a user. You can go to the Amsoil web site for more info.

Synthetic Manual Transmission and Transaxle

Gear Lube 75W-90 API GL-4 (MTG)

Specifically formulated for the most demanding manual transmission and transaxle applications

See Pricing Information or Place an Order

Package sizes include:

1-Quart Bottle

1-Quart Bottles (case of 12)

5-Gallon Pail

55-Gallon Drum

AMSOIL Transmission fluid recommendations for Cars and Light Duty Trucks

PRODUCT DESCRIPTION

AMSOIL Synthetic Manual Transmission and Transaxle Gear Lube (MTG) is a premium blend of the finest synthetic base oils and advanced, high-performance additives. It is formulated specifically for maximum protection in the most demanding manual transmission and transaxle applications where an extreme pressure GL-4 gear lube is specified, including those where high horsepower/high torque engines and towing or heavy loads increase transmission stress.

[Guest 36chev]

Thanks for the information! I'll see if anyone locally can get it.

But is Gear Lube 75W-90 API GL-4 (MTG) susceptible to leaking? I've heard that synthetics can be more prone to leaking than regular petroleum oils?

Unfortunately, the 36 transmission/torque tube design is inherently leaky. The u-joint runs in the transmission oil and there is no perfect way to seal the joints on the transmission and the torque tube.

Also, there is a supposed to be a cork seal inside the torque tube to keep transmission oil from running down into the rear axle, but the one on my car is long gone! Normally I add some oil every 500 miles or so.

Again, thanks for the input.

Edited July 29, 2011 by 36chev (see edit history)

[unimogjohn]

Amsoil does have a heavier weight that will work also. I would just put it in and watch/check it. You can always switch back. Good luck. And let us know how it works out.

I am sure there are local dealers/individuals in your area also.

[DavidAU]

Penrite also make gearbox oils for specifically older cars and it is avalible mail order from Restoration Supply Company in CA. (I have no connection with either company)

Classic Car Oil - Penrite Oil

info@RestorationStuff.com “The Right Stuff!” Phone: 1-800-306-7008

Restoration Supply Company

Penrite Lubricants

Transoil Range. Non-additive. Straight Bevel & Worm gears

Transoil 90 OK w/yellow metal 1-litre jug LUB029 $14 5-litre jug LUB037 $60

Transoil 140 OK w/yellow metal 1-litre jug LUB030 $14 5-litre jug LUB038 $60

Transoil 250 OK w/yellow metal 1-litre jug LUB031 $15 5-litre jug LUB011 $65

[Guest Bob Call]

Check with you local TSC (Tractor Supply Company) or similar farm store. Often they have oil, lubes and batteries that are recommended for vintage vehicles.

[TexRiv_63]

I used Sta-Lube brand SAE 140 API/GL-4 in my 32 Cadillac for both the trans and rear end, my local NAPA strore was able to order it for me. Sta-Luibe is made in the USA by CRC Industries. They may also have other viscosities available.

[Bill Boudway]

Hi,

I'll have a small quantity of Mobil 600 WT Steam Cylinder oil for sale at Hershey in quart containers.

Space C2I-44 in the Chocolate Field.

[Guest 36chev]

Thanks for all the responses! All sound like excellent options. I was hoping to avoid mail order, but it is possible that may end up going that route. Bill, I'll be at Hershey but am planning to get the car back on the road before then. We had the rear axle out as well as transmission, going through them and the engine.

While at Hershey last year I purchased the Penrite steering lube through Restoration Supply Co. and have been pleased, so will check to see how much shipping adds if order the gear lube. I could get some at Hershey from them but as in Bill's case want to have the car going again before then. It may seem that I'm being chintzy--but on my little budget shipping adds up!

Another reason for wanting to avoid a more expensive oil is the leakiness of the transmission/torque tube design. Plus it is not a high stress design. It is probably true that the synthetic will be the superior oil for lubricating properties.

Don, appreciate the NAPA suggestions. My hometown NAPA store is excellent for getting older parts and extremely helpful (however, the local one is not--interesting on how personnel experience and attitudes can make such a difference.) So I'll start out asking NAPA to order the Sta-Lube SAE 140 API/GL-4. 140 is the maximum weight recommended for the Chevy (summer driving), but since most of the driving is in warm or hot weather that should be ok. If this brand comes in a 120 weight I may try that.

P.S. One of the employees at the hometown NAPA collects vintage parts boxes. When I use a NOS/NORS part, I give him the the leftover box. Makes him very happy and may help me get discounts and better service.

Edited August 2, 2011 by 36chev (see edit history)

[Guest 36chev]

Follow-up: NAPA is ordering Sta-Lube brand SAE 140 API/GL-4. Since others may use it, (a number of antique car people frequent this particular NAPA) they're going to order a supply to have on hand. About $8.00 a quart, or if purchased by the gallon slightly cheaper. NAPA said their records indicate that 140 is the only weight Sta-Lube supplies for GL-4.

Edited August 3, 2011 by 36chev (see edit history)