.Correction: I dug out my BW OD manual and it says 40W motor oil for normal driving, 50W motor oil for hard driving but 80W mineral gear oil can be used, not to use an EP type gear oil..

As Daniel said, the manual says to fill the OD unit first then the main trans.

Glad you got it worked out. Those old OD setups are a joy to drive and a complete mystery to the uninformed. "I heard you shift 3 times but it's only a 3 speed. What up with that?"

I adjusted linkage today also, it was way off. Now it will stay in second gear driving through town in or out of overdrive (so far) but will still pop out downshifting to second, oh well I can live with that I'm just happy I can drive around town in second gear overdrive now. Next issue......

This OD/trans filling issue never seems to get resolved. If you fill the trans first, and then fill the OD to the higher level, the trans will eventually become overfilled (?), since fluid seeks it's own level, and the passage between cases is lower than either fill plug. While the logical approach would be to fill through the OD hole until the lower trans hole overflows, due to the extreme 90W viscosity (especially in cold weather), any expedient high-volume/quick-filling system results in considerable waste (or recovery hassle/mess) since there is much excess lube still left in the OD unit that is above the passage & trans fill hole when it actually begins to overflow. The only obvious way to avoid this problem would be to fill the OD in small drabs, over a long period. Those in a hurry though (with a high-volume fluid pump) who are economical & environmentally conscious will have spare/clean catch pan, and return later to replace the trans plug & rebottle the overflow.

6 VOLTS/POS. GRD. NW INDIANA

I have two OD trans, R11 in my 57 and a R10 in my 60 truck. I have the Borg Warner manual for the OD units and they specify using 30W oil in the OD unit. I have never done that, I've always used 90W gear oil which is about the equivalent of 50W motor oil.. Gear oil and motor oil viscosity are not the same.

GL-1 is right Dobie. Fifth Avenue doesn't recommend anything rated higher than that. They sell the oil but it's $30 a gallon. I got my oil from NAPA for less than half that price. I still have a partial jug left if you need the part number.

Durham Missouri

I should add that when you add oil fill the trans section 1st, then top up the OD. Don't rely on the passage between the trans and OD sections to lube the OD. If you'll notice, the OD filler is a couple of inches higher than the trans filler.

Oops! You're right! It's GL-4, not GL-1.

Ok cool, I will ask trans guy what he put in there, Thanks!!

80-90 is fine. Should be GL4, not GL5 which as stated earlier is for diferentials. Its a little hard to find. Finally had to order it on line to get it. Do not use GL4 in a diferental.