My 1940 Plymouth specs call for #90 weight oil for the rear and xmission. All that I can find on the shelves locally are #80-90 weight.
Can I use this instead of straight #90 or will it begin to seep through the seals? Thanks in advance for any advice.
you can in the rear end, but not in the transmission. The new hypoid trans oils are not friendly to bronze and brass use in the synchros assemblies of our old transmissions, usning the new style oils with the high shear additives, will quickly kill all the whitemetal pieces.
Suggest you go to a farm supply place and look for gear oil made for tractors and other farm equipment that does not have the modern additive packages.
Or if you have an oil distributor in your area Lubriplate still makes the stuff we need. Some of the new synthetics are OK for white metal but it must say so on the label.
Thank you plm46. You have saved me from making a bad mistake. I went to my local Tractor Supply Store and they have Traveller, all mineral, SAE #90 for Ford Tractor transmissions. It is rated at API-GL1. Is this the appropriate one to use in my 40 Plym transmission?
A company called Amsoil also makes various Synthetic oils many of which are good for using in old cars with Brass/Bronze gears!!! I've used their oil in the TransAxles of my VW's - '67 Beetle & '71 Bus - without any problems. I've added their website address below incase you want to check them out.
http://www.amsoil.com/index.aspx
Be sure to read the description of any product you're interested in before you buy, but you can also call and ask/tell them what you need and what it's for.
:)
I have missplaced my shop manual but I believe GL1 is the correct rating for our transmissions.
I pulled out the service manual for my 55 Plymouth. It states to use SAE 80 in the 3 speed manual transmission. As for the rear axle, Above 10 degree F. SAE 90 Hypoid Gear Lubricant. Below 10 degree F. SAE 80 Hypoid Gear Lubricant.
I hope this helps.
Plym46, CHS, & Gaby51, Thank you so much guys. Your input is most appreciated.