Transmission oil

[MidgetLover]

I know the transmission calls for 20W-50 or so, what are the consequences of running 85W, only in the summer.

 

[racingenglishcars]

Don't

Too thick oil film on gear teeth will seriously over-stress the gears and bearings. It also has that bad property of being difficult to pull into small areas where it needs to be, like bearings for example.

 

[aeronca65t]

Which Midget do you own?

Older cars with the A-series engines (948, 1098 or 1275 cc) are supposed to use conventional motor oil (I use 5W-30 in my racer but 10W-30, straight 30W or 20W-50 are fine).
These transmissions are mostly referred to as the "ribcage" or very early "smoothcase" units.

The newer cars with the 1500 cc engine and "Marina" trans require gear oil which is typically 85W-140.