TR2/3/3A TR3A Overdrive Conversion

[deadair]

I was able to source a rebuilt Type A overdrive unit and a TR3 overdrive mainshaft. Now the question is, should I attempt the conversion myself or send it out to a shop?

I'm very mechanical (just finished rebuilding a Honda Civic engine) and I've actually rebuilt transmissions before. (Bought an old Ford flatbed that I later learned didn't have any oil in the transmission and fried the halfshaft bearings.) However, I've read here and there that the TR3 transmission poses some particular challenges. Can someone summarize the difficulty level? Pointers to any technical resources that step through the procedures would also be very much appreciated.

 

[TR3driver]

If you've got the time, and the inclination, and the thought of making a few tools doesn't scare you; then I'd say go for it.

There are some good articles at https://www.buckeyetriumphs.org/technical/technical.htm for the fairly similar TR6 box. Also good stuff at https://www.vtr.org/maintain-index.shtml (the "Greasy Hands Garage Guides" series).

Converting to OD basically involves tearing down the gearbox as for an overhaul; then reassembling it with the OD mainshaft, adapter plate and switches. Since you presumably won't be tackling the overdrive, I'd rate it about the equivalent of your Civic engine.

I would also recommend checking the operating pressure on the OD before installing it. The rebuilders seem to overlook this step sometimes, and those old springs usually need some shims (even new ones do, sometimes).

You might also consider contacting your local club, which I believe would be Triumph Travelers: https://www.triumphtravelers.org/
Even if you don't care to have help, I'm sure they would have at least a few members that would love to come watch, hand you a beer, etc.

 

[sail]

Those are the two sources I relied on. The TR Workshop Manual is like Cliff Notes and Haynes got me lost in detail.
I have never done a gearbox and was apprehensive. You have much more experience than I. Took it slow and read both sources several times with each step. A speed shop was used to drill and tap the cover for less than the taps I found. They also pulled and pressed the counter shaft bearings although several here have done those. Access to a press would be nice but I made due. Everyone complains about the clip on second and third but not so bad.
Some said you shouldn't do a gearbox unless you have experience, but how do you get experience unless you do it? And there is a great deal of experience on this forum if you get stuck.
If new oil doesn't improve my synchro action taking it apart again will be much easier the second time.
It's kinda fun to see how it all works. The OD is great.
I would do it again and may be doing just that....once it snows.

 

[deadair]

Since you presumably won't be tackling the overdrive, I'd rate it about the equivalent of your Civic engine.

Dang! That Civic engine was no cake walk. Of course, the hardest parts were inventorying all of the wiring, removing the engine and the reverse. Then there was dealing with the inevitable post-op complications. In my case, this involved a stuck idle air control valve (IACV), which is a component I didn't even touch. The on-the-stand engine rebuild was relatively straight forward and routine.

Now that I'm done with the Honda, I'm ready to tackle the TR after a decade of neglect. My current challenge is to resolve an overheating problem. This time I'm attacking on all fronts and am confident of a fix. The next step is to do all of the fun upgrades, such as wire wheels and OD!

Thanks for the great info.

 

[HerronScott]

Sounds like you have far more experience than I had when I did the same with no more than the Bentley manual, a Haynes manual and some handwritten notes I had gotten from someone who had done it before (this was pre-Internet).

I don't think you will have any problems tackling it.

Scott

 

[tdskip]

As Randall said, there are some great resources in your neck of the woods if you need help. Good people to drive with as well.

Plus, once you have it up and running you can bring it on the Melee!

 

[Tinkerman]

I did both the tranny and the OD. The Nelson Reidel articles were priceless(Buckeye Triumph). I also had phone conntact with an gent in Jackson, FL which was priceless. Also much forum help which was also priceless. Boy I beat priceless to death, heh. Anyway go for it. Frustrating at times and gratifying when you are finished.

Tinkerman

 

[deadair]

As Randall said, there are some great resources in your neck of the woods if you need help. Good people to drive with as well.

Plus, once you have it up and running you can bring it on the Melee!

Yes, I've been meaning to drop into one of their meetings, which just happens to be tonight.