TR6 Do the HVDA [Toyota overdrive conversion] or repair my existing J Overdrive?

[glemon]

I have never had a car with a 5 speed conversion, but people I have talked to who have done it seem very happy with no regrets. That being said I love my O/D and I think it is one of the things that makes the cars unique and fun, I am not a stickler for 100% correct, but I think the O/D is one of the things that is cool about old British cars and when I was younger and drove MGs and Triumphs and such thought how neat it would be to have a car with O/D.

If my goal was ultimate performance I suppose I would go with a 5 speed as it is lighter than a tranny with overdrive, probably more reliable too but....

I think you are on the right track exploring possible "non-tear down" type O/D problems first, as, although they can be hard to diagnose, they are usually pretty easy and cheap to fix once figured out. Between my TR4A, Austin Healey 100, and current TR250 I have now owned a car with a Laycock overdrive for about 30 years. While I have had a few intermittent issues, some of which were head scratchers, I always figured out the fix, and it never involved tearing into the overdrive itself, so hopefully you will have similar luck.

 

[HerronScott]

I'd go for fixing the overdrive as I found it useful at times in 2nd, 3rd and 4th depending on the driving conditions plus you already made the investment in it.

Scott

 

[PeterK]

+1 on HVDA: Installed easily by me alone, no permanent mods so can I switch to J-type if I wanted (and if I had one). No cutting bending any mods to original stuff. Works flawlessly. If you have a modern car with a 5 speed, it's the same, smooth, rev-reducer.

The two kits I have:

 

[Gliderman8]

+1 on PeterK's post above. I installed my HVDA about two years ago and find it much better than the original 4-speed. With that said, if I need to change it back it's easy.
I think you are on the right track to try and fix your J-type overdrive, that makes perfect sense. Good luck.

 

[Kaybass66]

What might you do and why?

What have you done and how has it worked for you?

I bought a J overdrive from Down Under. You might guess the seller. It went in-op. Mechanic looked at it and said: "I'm not sure what is wrong with it, but the pump could be bad." I respect this mechanic. Further he says: "I recommend the Toyota ((Herman van den Akker, I suppose) overdrive/transmission conversion."

His thoughts are it would be more reliable in the long run.

That said, I have not tackled trouble-shooting on my own with help from the Forum my existing J overdrive. Yet another mechanic, which I may have mentioned already in another thread, attempted repair on the overdrive, and left me with it still in-op and a nest of wires laying all over my transmission.

I have read comment from at least one guy (Bloke, British politically correct version,) who said he did the conversion and got little to no reduction in
freeway rpm's. Frightening thought.

My objective is to relax the engine, save fuel and have it be reliable for daily driving.

I am torn, because I dream of having the existing overdrive working as it should because I like the flexibility of shifting as it does in third as well as fourth gears, and, I have read rumor of very cool setup from a Stag shifter with push button operation. Very cool, in my view.

So what do you think? What has been your experience?

Taking a look at what I have, to some degree, does make sense. It seems most guys' attitudes are to leave the overdrive and transmission stuff to the Pros. What do you think? Oh, and by the way, this is an add-on. My car came stock with a four-speed.

Don’t waste another minute with that J type overdrive. It’s not worth the trouble and the constant worrying about when it will fail, and it will fail. One of the joys of driving a British sports car is shifting gears and the Toyota five speed gives you that extra fun. As a bonus, you will absolutely love the hydraulic throw out bearing. Your clutch pedal effort will be sweet too. I’ve had mine for ten years. Do it soon as W58 transmissions are getting hard to find. You won’t be disappointed. Bill Stumm

 

[tr6nitjulius]

J-Type (4 spd to 6 spd) for decades no clutching/shifting to change in/out 3rd/4th OD simply flick a switch 70 mph 4th OD 2600 rpm vs 4th 3300 rmp. 5 spd conversions shift/clutch to engage OD

 

[malbaby]

I was in the situation where I had to decide wether to reco the OD box that I had bought, or buy and fit a Toyota W58.
Chose the W58 option...Replacement parts are not easily obtained.
A guy here in Australia makes/sells the conversion parts including the bell housing and the basic mechanical [not hydraulic] clutch operating system.
Currently in the process of fitting the gearbox to the engine.

 

[bammons]

I have the HVDA and like it. I have never had OD and my car came without OD so the HVDA made sense. My wife rides with me alot and it helps reducing noise to talk. But if you have the OD then keep it, don't get rid of it just because you haven't found a good mechanic. I will say that anywhere off the highways I often ignore the 5th speed, but we have hills and curves here. Bruce

 

[TR Tom]

I have the Toyota 5 speed and couldn’t be happier. It’s given me almost 400,000 trouble free miles. Of course it’s still in my 93 Toyota truck, as God intended.

As far as my Triumphs…
My first TR4 did not have OD and still would happily cruse at 100mph. This with four recaps and usually a 6 pack on the seat next to me. My teenage self was not very bright back then, I would not consider or recommend any of those activities now. My point being, they will still go faster than they should ever go without needing OD.

When going to buy my next TR3 and present TR4, both times the sellers insisted that they didn’t have OD. In each case I crawled under for a look, smiled to myself, and happily paid them their $1,000 asking price, commenting that it was too bad, as that would have made them worth more. In both cases the only thing wrong were sticking switches. The moral to this is there are a lot of very simple things that can be wrong with your OD, spend an hour or a couple bucks to look before assuming the worst.

In my opinion, you can have a heck of a lot of fun in a non OD Triumph (or one with non working OD, it will still drive just fine). On the other hand, there is just something magical about clutch free gear splitting on a fast winding road, it’s a feeling you just can’t get in many cars, at any price.

If however you have your heart set on a trouble free, smooth shifting, soulless Japanese transmission, you might want to consider a Miata, as the 5 speed will already be installed.

This is all just my personal opinion and is worth exactly what you paid for it. Whatever you decide, hope you have many happy miles of TR driving, see you on the backroads,

Tom

 

[TR Tom]

Oops
Just noticed I was responding to a 10 year old post…oh well, I guess it is an eternal Triumph question.
I would be curious though what the OP wound up doing