About converting TD5 to ZF4HP22

[petethepilot]

Hi all!

And firstly, yes, I have used the search!

I have a 110CSW TD5 with Borg Warner transfer box from 3.9 RRC. I want to convert that to automatic, but don´t have the thousands of pounds to go to electric with Compushift and all... And first of all, I´m not willing to spend that much on the gearbox, those prices are insane IMHO! When I was in UK last summer with my 110, attending the Newark LR show and "doing England" by car for two weeks, I really considered taking my car to Dave to get it converted to TD5 Auto, but then came to my senses...

The thing is that my friend has a LR and Jaguar garage and he has 3 RR classics wrecked on his yard. All of them are 3.9 V8 autos, so you probably guess my question now following... Btw, that´s where I got my tranny...

So, can I use one of those 4HP22 to convert my TD5 to automatic, will the bell housings and flexplates and so on fit to TD5 and mostly, is it going to work on TD5? I mean locking, gear change etc. Job is not a problem, I can do it myself, using their professional tools and help. My point is that if I can make them fit, I can order stage II upgrade for 4HP22 from Ashcroft, and that´s about it, could do almost everything by myself and save a huge amount of money!

I also like the idea of keeping it all mechanical, and yes I do know the difference in those gearboxes in a matter how they change gears and how refined they are. I mean the difference between 4HP22 and 4HP24E, because I used to have a Disco 1 300Tdi Auto, and RR P38 Diesel Auto. That 4HP22 suits me fine in Defender, if it is going to fit and function.

So does anybody know what parts will fit and what do I have to obtain from TD5 Discovery automatic to make the conversion, and I mean gearbox wise, bell housing, starter ring, any adapters etc.? Everything else I can rob from the RRC. I even have RR seats and cubby box in my 110. Luxurious...

Any info would be appreciated! I have called Dave, but didn´t get the straight answer, or maybe just didn´t understand, outlander I am...and my technical English is not perfect, and your accent is sometimes so thick, it´s hard to follow in the phone, so written is good...

Cheers,

Pete

[martifers]

There must be quite a few that have done this, so... answers to Pete's questions above would benefit many I would have thought, including me

[Dave W]

In purely mechanical terms you can put a 3.9 ZF onto a TD5 using the bell housing, torque convertor and flex plate assy from a Disco 2 TD5. You will also need to modify the throttle peddle to provide the "kickdown" facility by adding a mechanical cable to it. Not certain but I think the oil pump/torque convertor fitting is the same between the two... if not you may have to swap that too.

In driving terms it won't be a particularly nice conversion to drive because the box will change gear at the wrong rpm. Just how bad it'll be I'm not sure as I've not tried it myself. You might be able to tweak it a bit with the kick down cable adjustment to improve it. I'd hazard a guess that the gearbox would keep the rpm a bit too low when locked up and a bit too high when it's not which would make cruising both hard work and fuel inefficient.

If you're electrically minded and don't mind working on the bleeding edge a bit, you could drive an electronic D2 box using a Megashift (gearbox controller spinoff project from the Megasquirt project). That would give you a much cheaper way of controlling the electronic ZF than using a Compushift.

More here...

http://www.msgpio.co...hift/4L60e.html

I was going to go that route myself (and may still do at some point) but I was fortunate enough to get hold of a cheap Compushift unit instead.