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TR6 TR6 Tranny on a TR3B

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ICE MAN

ICE MAN

Freshman Member
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Aloha, I installed a TR^ Trany w/ J O/D in my TR3B. It looks like it sits higher than before. I do know the Tunnel hits the O/D switches on top. The fuel pump seems to be in the way of the steering column. Has any body done this before and had problems with the height?
Mahalo, Tom

PS: I was going to attach a picture, but don't know how T
 
I think I had one on my TR4 at one point and it was not a problem, but it did not have the O.D. I wonder if the reat mount is different. Perhaps all you need is a new rear mount. Check the parts numbers and see if they are different.

I know when I put the TR3 gear box on there (temporaroly) it seemed to fit exactly the same. And then once I got the TR4 one it was again the same as the previous two.
 
I have a TR6 gearbox fitted with a TR4 A-type overdrive fitted into my TR3. It was a bit of a squeeze as I think that the TR6 gearbox is about half an inch longer than the TR3/4 box. I think the difference is in the thickness of the bell housing. You would have to compare the J-type mounts with those of the A-type to see if they are different. Anyway, with my set up the engine mountings and the gearbox mounting are pushing apart slightly, so the fan is slightly closer to the radiator, but not by much. Certainly it sits at the same height and the fuel pump is not interfering with the steering.
Nick
 
NickMorgan said:
I have a TR6 gearbox fitted with a TR4 A-type overdrive fitted into my TR3. It was a bit of a squeeze as I think that the TR6 gearbox is about half an inch longer than the TR3/4 box. I think the difference is in the thickness of the bell housing.
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I have the same arrangement. Although the bellhousing flange is thicker, the distance from the flange face to the first bearing is the same (meaning the clutch mechanism can be the same). The extra length is in the gearbox itself, to accomodate the synchro ring on 1st gear. I just drilled new holes in the rear cross member, to move the rear mount back by 1/2" or so. Since my TR3A is a pre-50K model, I also had to massage the transmission tunnel a bit, to clear the larger starter bulge. But no trouble with anything else moving or hitting.

A TR J-type has a completely different rear mount, unlike the A-type; and also sits farther back from the gearbox (making it much larger at the rear crossmember). IMO, the OP's problem is the rear mount. When the TR6 converted to the J-type, they had to fabricate a 'dropped' crossmember to get the OD at the right height.

I've also heard that it's necessary to notch the frame to get a J-type to fit properly in a TR3.
 
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