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overdrive but which one...

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skagroovy

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i have a 71' that is now running well after all my little problems have been solved, it's a daily driver to work and back 8 miles total and would like to look for a used overdrive what is the difference between a A type and a J type overdrive. Is one better than the other as far as reliability?
thanks
 
A type would have been the correct one for your year car. A type shifts harder, understand the racer like it better. J type smoother. I believe you can get more options of % per cent of overdrive with the J. Std is around 22%, I have a 28% (Volvo unit) on mine and there is a 32% I've heard but not seen. Reliability about the same if both are maintained.

Marv
 
IMO, the J-type is probably more reliable, as well as being more serviceable in the car.

But installing one in an early TR6 involves some extra work, including cutting off the frame where the old rear crossmember attached, and fabricating a new crossmember.

Personally, I much prefer the A-type in my TR3 over the J-type in both Stags. I'm actually kind of sorry I put in a J-type (but Stag A-types are very rare on this side of the pond).

If you do go with an A-type, be sure it's the later type unit with the small accumulator piston. They had to soften the shift somewhat for the IRS cars.
 
If it helps, the later A type softened shift overdrive for IRS TR's is tagged 22/61753.

I put a J Type in the TR5 and it was acceptable, but it was a powerful car, so we only hooked up the overdrive to top gear.

Viv.
 
I put an A type in my 71 and all you have to do for the harsher shift is push the clutch in like changing to another gear

Hondo
 
skagroovy said:
...it's a daily driver to work and back 8 miles total and would like to look for a used overdrive...
Click to expand...

I love my overdrive but unless that 8 miles is covered in 7 minutes I don't know that an OD will bring you much joy.

Where I like it best is long fast cruises and twisty mountain roads.
 
I love the J in my TR6 with the modified engine. It shifts both in and out quickly and has been very reliable. I love driving back roads and just flipping up and down in either 3rd or 4th gear to pickup speed or slow down.
 
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