I have a 1935 model E Cletrac and want to change the transmission and final drive oil. At TSC I find 80W-90 and 85W-140. Is one of these suitable?
I have the original Cletrac Lubrication Recommendations book, and it mentions SAE 30, SAE 40-50, and SAE 60-70 depending upon the temperature.
Most 80W90 and 85W140 are GL5 gear oils that have EP additives that are not good for the band brake of the steering system. Look for a GL 1 gear oil or use a SAE 50 motor oil.
The book calls for 50 wt non-detergent motor oil. My E currently has 50 wt detergent motor oil as I couldn't get the non-detergent the day I needed it. It steers very good, but then there is little weight on an E so it should steer easy.
Many on here use the GL-1 gear oil. I guess the choice between these two would be price and availability.
See the topic entitled 'Where to get transmission oil in Canada?' on the HG, OC3, OC4 forum. That gives some products and prices.