View Full Version : TR6 Tr6 4 speed to 5 speed conversion?

Bret Cutler
08-04-2002, 01:46 AM
what is available for a 5 speed conversion. Are there any that are simple and not 3000 dollars like the one i see from the uk. I think it uses one froma 300zx or something. Please let me know if you can.

08-05-2002, 02:04 AM
Hello Bret,
Have you looked for the Triumph Overdrive gearbox?
In my opinion this is superior to a five speed set up. It will give you a six speed option,(even if O/D 3rd is about the same ratio as direct 4th.)
The beauty is the instantaneous up change at the flick of a switch, ideal for overtaking.

08-09-2002, 01:02 AM
My good fortune was to happen upon a parts car that contained an A-type overdrive. I took the entire tranny and had a very simple bolt on solution. I would highly recommend a triumph overdrive. That way, you have no re-engineering to perform. Just a bolt on solution.


08-18-2002, 12:40 AM
I know of a GT6 in the NorthWest that bolted on a Toyota truck tranny to his six. Shifter was kind of funky, but it worked. Also had a different rearend too. images/icons/confused.gif I think he had played with the motor and put the TR6 crank in it too.

08-18-2002, 09:07 AM
Far better off going with the overdrive option, less hassle and works very well, not to mention, cheaper all round.

08-20-2002, 12:15 AM
I did some preliminary research on my six till luck got me a Jtype od. The rear plate is easily modified(half the battle) The 5 sp from a Toyota pickup is a good physical match, and though I didnt get too far with the project, I would suggest it as a good start(circa 1985 appx) it is easy to find and cheap. Good luck

Bret Cutler
08-20-2002, 01:09 AM
thanks for all of the help. I have the supercharger and have picked a carb and nitrous kit for my engine project. Thanks for all of the 5 speed advise.

Bret Cutler
08-26-2002, 03:55 AM
So the other consideration was strength. Are the 4+2's strong enough for a couple hundred horse? How much heavier are the overdrive trannies? Are they larger physically. Not sure how much more room i have underneath my TVR. thanks,

Rob DeScherer
09-06-2002, 07:08 PM
There is aqn advertisement for a website in British Car magazine- www.conversioncomp.co.nz (http://www.conversioncomp.co.nz) --
it is in New Zealand, but they will give advice as to which transmission would be a good fit for your car. The editor of the magazine wrote that they are very nice people, and are happy to give the advice. There was also an article in the August - September issue about tranny 5 speed conversions.

09-09-2002, 01:38 AM
I believe my A-type OD is the same length as the stock non-OD trans. The OD replaces the rather long tail housing of the non OD trans. The only difference I recall is that the rear trans cross-member is different.

That said, I have serious doubts that the stock Triumph sun-gear type OD will handle the torque you are likely to generate. I suspect a conversion to a modern 5 speed would be a better long term solution. Just about anything that was pushed by a sporty V-6 or V-8 should do the job. I had a T5 in a 5L mustang that had a nice short throw and was pretty bulletproof. The trick will be the bell housing, linkages, and shifter positions - I can't offer any help there.

BTW, I sure hope you're paying attention to the brakes with all the power mods you're adding.

Good Luck

[ 09-08-2002: Message edited by: TerrierCarrier ]</p>

09-10-2002, 12:46 PM
Hello Bret,

I take your point about power, and although the O\D can be beefed up I don't know what it would be like with what you are anticipating. (I do have the same A type O\D on my Jaguar 3.8 saloon
with about 220 bhp, but it is only for 4th gear. You could do the same for your set up). The O|D box is the same lenght as non O\D but a bit heavier of course.
Just a thought, if there are any around, TR7 5 speed box, these were used in TR7's, TR7 V8, Rover V8 saloon (sorry sedan) and the Jaguar so it should be strong enough. With luck all you may need to do is fabricate a new backplate for your

Trevor Triumph
09-19-2002, 11:54 PM
There was a guy at Triumphest that engineered a Toyota Five speed to TR engines. I think it was in 2000 in San Diego. One our club members here in Phoenix AZ has such a transmission. I don't remember the cost. Check out the DCTRA wedsite &lt;www.dctra.org&gt; to find more about it. TT.

04-03-2005, 09:18 PM
I have done this conversion and it is really slick I used a toyota celica tranny and a coversion kit from a Herman Vandenaker from California no welding or drilling aprox $1100 not including tranny let me knoiw if you are interested I'll find the info John

04-03-2005, 10:45 PM
Here's the kit that I purchased. http://www.blindmoosefab.com/hvda.htm
It uses a Toyota Celica or 2WD truck tranny and retains the stock shifter. Optional (recommended) is a hydraulic t/O bearing (no slave). Haven't finished my 4A to drive it yet but I have driven a friends and it's smooth and reliable (as a Jap car would be). PeterK