'89 760T transmission swap?

[shahirmy]

Hi all,

I'm from Malaysia and currently owns an '89 760T which was imported from the UK in 1995. Engine is B230ET mated to ZF4HP22 box. Right now the ZF box slips badly in every gear whenever the boost starts to kick in.

I have 3 options for the gearbox:

Option 1:
I might be able to get my hands on an M90 from a 940 which is rare here. Is it just a bolt on change? What are the parts related that i need? i know i need the pedals, gear lever, clutch pump, front propeller shaft and the mountings. What about the flywheel? Another concern is regarding the crank sensors. Since B230ET motronic has 2 crank sensors and while LH equipped cars has only 1 crank sensor. Will the M90 fit in?

Option 2:
Send the ZF box for rebuild.

Option 3:
Swap with AW71 from a 940. Again the issue is regarding the crank sensors.

I would prefer the option 1 and need some advice for the swap. Has anyone successfully done it? Opinions and inputs from other members here are much appreciated. Option 2 & 3 are also fine to me as long i'm able to boost again.

Thanks.

[czech240]

goes under the name of baggy798 on here....think he has done this....search a ye shall find! :-)

[baggy798]

You will need the flywheel from a car specifically equipped with the B230ET, or maybe a 240/740 with a B230E. I say maybe because I got mine from a franken-240 that had an odds and sods rebuilt B230E.

The 2 crank sensors fit fine with an M90. Not sure about AW71, but a bit of grinding would sort it out.

Regarding the ZF, have you tried replacing the oil? Maybe someone can advise if that would fix the slipping?

[Prufrock]

Originally Posted by baggy798

Regarding the ZF, have you tried replacing the oil? Maybe someone can advise if that would fix the slipping?

Replacing the oil would be my suggestion...the ZFHP22 is a well proven and almost bullet proof gearbox, and widely used in many cars (BMWs especially).

I had a 735 with an HP22 and had some minor issues - with an oil change and filter screen cleaned it was transformed and ran fine for many years.

Prufrock.

[shahirmy]

thanks for the replies guys.

I have to dump the idea for m90 swap as the seller's asking price was too expensive.
I did changed my ATF right after the slippage started and did not make any difference. In fact i changed my ATF with synthetic fluid every 3 months along with engine oil. I'm using TD04-16T for my B230ET,always on spirited driving style with frequent high speed run on the highway. That's why i changed the ATF every 3 months in order to keep the ZF in good condition. Yet, it decided to give way.

I think i might send my ZF4HP22 for rebuild as i still prefer ZF over AW.

[B10B]

Given that your car is producing more power than standard, you've probably over stressed the ZF.
I don't know how to post links but if you goggle Ashcroft Transmissions there is a whole bunch of information on their site about the same ZF used in Range Rovers and the problems with over stressing them, they are UK based.
They also have an extensive range of strengthened parts for the ZF, if you thinking of having yours rebuilt and importing costs are reasonable for parts it could be an option?
If ever i have a problem with my gearbox this will be my course of action.
HTH