A type overdrive repair and test

[TFR]

Well, I tried all I know to do on the transmission while it is in the car. Have ordered a test pressure gauge and it should be here soon.
Where do you fill the oil for the transmission? Is it the same oil as the gear area and is it filled in the same place?
I've read where some people think 30w motor oil is what should be run in a transmission with OD. What do you guys think?
Any other checks would be appreciated.

 

[Geo Hahn]

Same fill hole, same oil... gearbox w/OD takes more. Generally I have to fill it, drive a bit, then fill the rest of the way as I do not think the OD unit fully fills in the first go-around.

I use 30W non-detergent -- many different opinions on this.

 

[TFR]

So I can drain the HD oil and refill with 30WND? How much does it hold?

 

[Harry_Ward]

I use 20w-50 valvoline racing oil at the suggestion of Don Elliot. No problems for going on ten years. John Esposito, Quantum Mechanics -

https://www.quantumechanics.com/index.php

who rebuilds em for a living did an extensive test of the A type available oils and found that straight 30wt works best. The fill plug in the side of the tranny box is also the fill for the OD - Fill it until it just starts to back-flow out the side plug hole. Make sure though that you have filled to point of overflow. Sometimes an air pocket develops and oil will come out prematurely. When you think it's full I suggest you let it sit for a bit and then try to fill it again. Empty gear box with empty OD should take 3.5 pints. In the Moss Motors TR2-3-4&4A parts catalog there is a good OD troubleshooting guide on Page 39 of the latest catalog or here on the web for a start,

https://mossmotors.com/forum/forums/10796/ShowThread.aspx#10796

I believe Randall said he has the factory OD repair manual in PDF format if further work need be done.

 

[TR3driver]

-- many different opinions on this.

Indeed there are, and I suspect the lack of any clear consensus indicates that it isn't all that critical, especially if you don't drive the car hard.

But the legend as passed to me is that Standard-Triumph (by then part of BL) changed their recommendation away from ND because they were getting failures of the gearbox thrust washers under warranty. And since the washers are a known weak spot, that makes sense to me.

So, I've followed HVDA and BFE's advice in the past, and used Valvoline 20W50 'racing' oil in my A-types. In the future, I plan to try Redline MT-90.

 

[TR3driver]

How much does it hold?

Drain & refill is 3.3 US pints, according to Practical Hints.

 

[Don Elliott]

From your Comm. No., and if it's the original gearbox, the fill hole should be on the left side about half way up the side. On the late TR3A I rtestored last year, I made a hole in the side wall of the tunnel to make it easier to fill the gearbox and overdrive. Like Randall, I have used Valvoline 20W50 Racing oil for the last 17 years. I have driven 98,000 miles and had to re-build the gearbox once (2004) because of my mistake. Not because of poor reliability.

 

[TFR]

Is it possible to remove the OD section with out removing the transmission? Where is the strainer section as mention in the Triumph register maintenance section.
I'm going to drain the oil and then replace it with the 20w50 Valvoline (as a test).

 

[DougF]

The entire tranny has to be removed to split the transmission from the OD. I wouldn't do this without the proper manual.
The filter screen is behind the large brass plug at the bottom of the unit.

 

[TR3driver]

Larry, I've lost track ... what problem are you trying to solve ? Or is this just a used OD that you are trying to test before installing ?