Gear oil

[dezwartj]

I am having a hard time finding gear oil for my TC locally. Alberta is oil & gas country but just ordinary SAE140 as is required for our gearbox, differential and steering box is next to impossible to find nowadays. Shops do have 85/140 gear oil but I am not sure if that could be used in our aging gearboxes. Your opinion please...

Josh de Zwart
Calgary, Alberta?

[Steve Simmons]

85/140 should be fine. The second number is actually the true viscosity. The first number is the cold viscosity which is achieved through modifiers. You should also be able to order whatever you need online. Redline has a product that is recommend specifically for our gearboxes. See:

https://www.redlineoil.com/75w140-ns-gl-5-gear-oil

Some people have also had good luck with Redline MT-90.

[Rob Reilly]

85W is the Winter viscosity specification, measured at a very cold temperature. 140 without the W is the summer viscosity specification, the same oil measured at a very warm temperature.
When these cars were new the oil producers didn't have the winter specs. They just specified the summer viscosity.
SAE 85W-140 is fine.

[Duncan M]

I ran a name store brand GL4 140W in the transmission and rear end, until after one summer when I checked the dipstick after a drive and it only registered foam. Now I only use the 140W in the BC steering box. Multi-weight in both transmission and differential, and no more foam.