Oil weight for 1931 Chrysler CD8 Transmission and Differential

[Gunsmoke]

The operating manual for '31 Chrysler CD8's calls for "high grade fluid gear lubricant" in transmission and differential, but offers no weight suggestion, other than "for proper grade consult the nearest Chrysler distributor or dealer"! Any suggestions on what weight they meant or used? I used 600W cylinder oil in my '31 Chevrolet as that is what GM specified, but it is quite a heavy oil, equivalent to about modern 300 weight. I drained the old transmission oil out and it appears to be perhaps 90-140 weight. Car will only be summer/warm weather driven so oil should not be a cold weather driving issue. Thanks for any advice.

[FLYER15015]

I use Penzoil "Synchromesh" oil (in the yellow bottle). in my '31 CG.

Sure looks like 90-140 weight.

Going up thru the gears is easy and quiet.

Coming back down, I have to double clutch.

 

Mike in Colorado

[viv w]

Ford model A was originally 600W, but the suppliers and club say 600W today is equivalent to EP140.

 I have used EP90/140 for years in my Model 50 and 52 cars with no problems and I am sure this will be fine in your car.

 

[maok]

There is also Penrite's T250 transoil, which I used in my '28 Chryslers gearbox and diff. Definitely helped with changing gears.

[stakeside]

I use 600 wt in my 29 DB truck trans. This trans does not have seals for front and rear bearings and there is no oil dripping from the trans.

If your trans has seals you can use lighter wt of oil.