C22 Overdrive gearbox Oil recommendations please

[trickydicky43richard]

My Chrysler workshop manual's Lubrication chart does not provide an Oil Grade type etc for a gearbox with overdrive, it does mention it but refers you back to the transmission section which also has no oil fill recommendations? or is it dummy me.

The standard box uses Std 140 gear oil in summer and 90 in winter, I noticed one other post where Chrysler recommends Aircraft 70 Engine oil for the OD box? .... Sae140 gear oil? and 70 aircraft engine. ???  oil these two types are miles unlike.

Looking forward to all input.

Richard in Oz

[c49er]

We use 85/140 in a 35 Aiflow C2... front and rear of the OD transmission.

[trickydicky43richard]

bumped up for answer!

[padgett]

Looks like it may have used a Warner (now Borg-Warner) TR14 overdrive. Have you contacted them ? I came across something that said fill with hypoid 90 wt gear oil and mentioned for both front and rear but was about much later Fords..

They became popular again during the first fuel crisis: you could drill one hole in a Saginaw four-speed and bolt on a Warner OD to lower the gear ratio. At a time when a 70 mph cruise was at 3,000 rpm with an "economy" axle that was quite useful.

[Grimy]

I'll respectfully contest the use of **hypoid** (i.e., GL-4) gear oil in B-W overdrives, although I used it for years with no ill effects until I found a 1948 Willys owners manual which was very explicit:

 

That manual very explicitly said to use **hypoid** gear oil only in the differential and nothing but "straight mineral oil" (i.e., GL-1) in the transmission and overdrive.  The reason was not given, but from other research I deduce that they were concerned about the effect of sulfur in hypoid oil adversely affecting the yellow metal in synchronizers, bushings and thrust washers.

 

My point in mentioning this is to advise against the use of GL-5 (used for limited-slip diffs and which is almost exclusively found on parts stores' shelves today), which is more pernicious to yellow metals than GL-4.