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Overdrive Identification

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M_Pied_Lourd

M_Pied_Lourd

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Afternoon All,

I am trying to identify the type of overdrive that I have just removed from my parts car, a 60 TR3A. I cannot read any of the numbers off the tag as they are pretty worn. It is not an original overdrive car and I think this was added to the car between 16 and 20 years ago.

Here are some pics.
P1030431.jpg


P1030429.jpg


P1030430.jpg



Thanks for your help.

Cheers,
M. Pied Lourd
 
It looks somewhat (but not exactly) like the O/D in my 1958 TR3A. Mine is a Type A overdrive and has been in my TR from new. See photo. Also I don't have synchro in 1st gear.

Yours has the horizontal solenoid where mine in mounted vertically. During the production of the TR6, S-T changed from the A O/D to the J Type O/D which has a horizontal solenoid like the one you show.

If your gearbox has a thick flange all around the bellhousing and synchro in first gear, then I'd guess that the entire G/B + O/D came out of a late TR6. Does the gearbox look anything like the one in the TR6 you previously restored ?
 

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I think it is an A type, but maybe out of a Stag which had the solenoid horizontal.

Coincidental timing, I just took a 5 minute break after stabbing my transmission back in the car after a clutch redo. Last time I did it was 20 years ago, it was a pain. Hasn't changed a bit. I cleaned up the trans before I put it back in, and I thought it had been messed with because I saw a painted red bolt. Don's picture above makes me think otherwise now.

Randy
 
Definitely an A-type. The J-type is considerably different in appearance, including a finned plate on the bottom, and the solenoid screws directly into the main casting rather than hanging off the side like an A-type.

As noted, has a different solenoid mount than usually supplied for TR3, but that style was used on other cars. Could be the mount from a Stag, but the OD main housing looks to be earlier than that (only the early ones had the brass tag on top where it can't be read with the gearbox top cover in place).

Gearbox looks to be a 3-synchro TR3 box, with the flat sides.
 
PS, check the OD ratio if you can. That may be a Healey unit with one of the taller OD ratios.
 
Randy, those bolts are painted red to notify you that they are the first in last out when you are working on it. Behind those red bolts lurks the very large accumulator piston spring, which would break things if you undid those red bolts first.

Cheers, Tinkerman
 
Hi Don,

I do have a J Type in my TR6 but it is not at all like the one pictured. My J has the finned bottom plate as Randall states.

I believe that the box is a non syncro 3 box. There is a tag mounted under the top cover but it is worn and hard to read.

Randall, how do I check the OD ratio. I know that the first two numbers on the tag usually indicate the ratio.....it looks like my first two numbers are 20 but hard to tell.

Any chance this is a Volvo unit?

Cheers.

M. Pied Lourd
 
Think you've got a pre 1973 Triumph saloon A type overdrive, as they had the horizontal solenoid. The vertical solenoid overdrive was used for chassis clearance on the TR sports cars.

If you want to chase a correct TR3A o/d, its number on the tag is 22/61374.

Regards,

Viv.
 
Thanks Viv,

I do have an original A Type in my other 60 TR3 restoration project as well. Haven't started on that car yet.....Maybe in the next few weeks.

Cheers,
M. Pied Lourd
 
Sorry, Pied, I can't think of any reasonable way to check the ratio. If you had some way to pressurize the operating pistons, you could count the turns, but that's probably not reasonable. And I don't know the gear tooth counts offhand.
 
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