Toploader installation.
 

I’m installing a truck based toploader in a 39 sedan. What trans fluid are you all using in the top loader?

Re: Toploader installation.
 

From what I have read, 80W-90 GL4 is recommended.

Re: Toploader installation.
 

GL 1 available from tractor supply for use in Ford tractors--straight mineral oil, GL 3/4/5 from experience will melt away your syncro's

Re: Toploader installation.
 

GL3 rating was updated to GL4 rating many years ago. It is still a mild EP and mild EP lube was recommended by Ford for the overdrive transmissions of the late 40s & 50s. While synchro blocker rings are yellow metal, they aren't as soft as the phosphor bronze bushings used in the early transmissions. Most of the worry was about the bushings and thrust washer in there. Mild EP is fine but no-EP lubes like GL1 will work OK if the vehicle is driven lightly like most antique vehicles are.

I still use Aeroshell W100 motor oil with no plus designation for my old transmissions. It is expensive but it's good stuff. It's an SAE 50 motor oil that has the same viscosity as straight SAE 90 gear lube. A person can use GL5 in the rear axle since there are no bushings in there.

Re: Toploader installation.
 

Alan, that goes against Ford's recommendations, they recommended mild EP gear lubricant for transmissions. That would be GL4 in todays world.

Re: Toploader installation.
 

use what ever you choose, butwhen you have to put thrust washers and new syncro's in your then you will change

Re: Toploader installation.
 

Ford lubrication chart. GL5 will damage "yellow" metal in transmissions, but GL4 is what is called out for these trans.

Re: Toploader installation.
 

Thanks guys. Good advice.

Re: Toploader installation.
 

The one thing I was looking for in the chart is capacity of the differential. It's not listed. Does anyone know what it is? Thanks!

Re: Toploader installation.
 

It takes 2 1/2 pints.

Re: Toploader installation.
 

One thing I forgot to ask yesterday is what truck is this transmission from? It could be a T170 RTS for all we know. I can't see using a truck transmission in a car unless there is some advantage.

Re: Toploader installation.
 

Early 50’s I think. It’s a conversion to allow the top loader with a closed drive shaft. Good for after the body is finished. No need for major work underneath.