New four speed auto?

[trollybus]

I fancy fitting a four or five speed auto to my 76 TC in place of the BW65.
Anyone got any info on this conversion.?

[sorbs]

I vaguely recall that the conversion uses a ZF 'box from Jaguar and is more commonly fitted to Stags.

Browse some of the Stag sites, ie. Monarch, or give them a call to see if you can find any info.

Of course, it would be feasible, if rather a lot of work to fit an overdrive to a BW 3 speed auto. It could even be automatically switched using a basic PLC with a road speed and throttle pedal input...........

[Jonathan Lewis]

I vaguely recall that the conversion uses a ZF 'box from Jaguar and is more commonly fitted to Stags.

ZF 4HP22 from the early XJ40. I am pretty sure that there used to be a company based in Worcestershire (Evesham?) offering these conversions for Stags. The Ford 4-speed from the Sierra/Granada can also be made to fit - there was a very detailed article in Six Appeal perhaps five years ago describing the conversion.

Of course, it would be feasible, if rather a lot of work to fit an overdrive to a BW 3 speed auto.

In theory, yes. In practice, however, I'm pretty sure that you'd need to incorporate a lock-up feature on the torque converter to prevent the transmission from flogging itself to death with the o/d engaged. Jaguar experimented with a not dissimilar set-up in the form of a two-speed rear axle (imagine a normal diff only with an o/d unit grafted onto the front) coupled with B-W and GM three-speed autos during the 1970s, and I think that set-up also relied upon a locking torque converter.

[Alan Chatterton]

Tate & Lewis in Birmingham are the people that do the ZF 4HP box from a Jag to a Stag. Very nice kit, costs about £2k.

It will fit a 2000/2500 but you need to "modify" the tranny tunnel to get it to fit.

One of our members was quoted about £3k supply/modify and fit a couple of years ago.

Drove a Stag with this box in, very VERY nice.

Cheaper option, just convert it to a manual with overdrive....... simple and cheap to do!

[sorbs]

Cheaper option, just convert it to a manual with overdrive....... simple and cheap to do!

But then you'd have to change gear yourself. Like on a tractor!

Actually, I'm pretty sure that even tractors have automatic transmissions these days.

[sorbs]

[/quote]
In theory, yes. In practice, however, I'm pretty sure that you'd need to incorporate a lock-up feature on the torque converter to prevent the transmission from flogging itself to death with the o/d engaged. Jaguar experimented with a not dissimilar set-up in the form of a two-speed rear axle (imagine a normal diff only with an o/d unit grafted onto the front) coupled with B-W and GM three-speed autos during the 1970s, and I think that set-up also relied upon a locking torque converter.[/quote]

I'd say that as long as the overdrive didn't engage under heavy load below about 50mph you may just get away with it.

If I ever get around to trying this I'll let you know how I get on...........

[Jonathan Lewis]

I'd say that as long as the overdrive didn't engage under heavy load below about 50mph you may just get away with it.

Perhaps - certainly, thoughtful use of the o/d when cruising could help obviate the chance of unwanted downchanges by the autobox under load, but I'd still be worried about the possibility of the converter being in a semi-permanent state of significant torque multiplication with too high an overall gear ratio.

Who knows, however? - it might work, and you can even get standalone in-line units (http://www.odspares.com/phdi/p1.nsf/sup ... ent&part=4) if your enthusiasm runs that far!... (and pocket that deep... )

[trollybus]

Thanks for the replies.
Jag ZF out of the question in Australia due to costs.
I would be looking for something readily available from the Japs the General or Ford.
An overdrive on the existing auto is a bit too out there.

[Jonathan Lewis]

Jag ZF out of the question in Australia due to costs.

Ah, after posting my response I did wonder whether I should have taken your Avatar as an indicator of approximate location... Roughly the same ZF transmission was also used in BMWs, Mercedes and quite possibly others (if that makes things any easier), though there may be slight differences between their versions and that supplied to Jaguar. You do, however, want the earlier 'mechanical' 4HP22 rather than the subsequent electronically-controlled 4HP24 (unless, of course, you're a whizz with ECUs and the like!)

I would be looking for something readily available from the Japs the General or Ford.

Toyota's RWD manual 5/6-speed boxes seem to be a popular transplant for TRs and even Jaguars. Do they do a corresponding auto which might meet your requirements, I wonder? I will see if I can search out the Six Appeal article on the Ford transplant to see if the exact type of transmission used is identified - with any luck, Ford used the same sort of unit on Oz-market cars in which case it might be of relevance to you.

An overdrive on the existing auto is a bit too out there.

One can but dream...

[Mike Stevens]

ZF 4HP22 from the early XJ40.

Also from 1994 - 1997 X300 using the 3.2l engine. The 4.0l uses the electronic ZF 4HP24. Later V8 cars uses the 5 speed 'sealed for life' unit. It's true, they are sealed for life, but the life can be short!

Guess how I know!

Cheers,
Mike.