Classic Automatic gearbox 1991

Thank you for your reply, Ratea

And so I can end this thread by confirming that my RRC '91's auto transmission has been fixed. Shifting from 1st to 2nd at 2500, 2nd to 3rd at 2500 and 3rd to 4th at 3000 rpm. Does it sound right to all the experts out there?

Noiriht said:

And so I can end this thread by confirming that my RRC '91's auto transmission has been fixed. Shifting from 1st to 2nd at 2500, 2nd to 3rd at 2500 and 3rd to 4th at 3000 rpm. Does it sound right to all the experts out there?

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Depends on throttle position.

If that is light throttle then No.

+ 1 to Henry's answer.
It might be better if you stated the road speeds that the up-shifts occur & the related throttle openings.

The further you push the pedal down the higher the change RPM, but generally it looks OK.

norseman said:

+ 1 to Henry's answer.
It might be better if you stated the road speeds that the up-shifts occur & the related throttle openings.

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The road speeds are as follows: ( in km/ hr) 1st to second around 20, 2nd to 3rd around 40, 3rd to 4th around 80- that is in mph 12, 25,50.

I am unsure how to state the throttle position but I was light on the accelerator pedal.

The 3.9 should sit around 2000-2200 rpm when accelerating under moderate throttle, it should gain speed and upshift through the box and finally go in to lockup 4th at 55mph if memory serves.

Noiriht said:

The road speeds are as follows: ( in km/ hr) 1st to second around 20, 2nd to 3rd around 40, 3rd to 4th around 80- that is in mph 12, 25,50.
I am unsure how to state the throttle position but I was light on the accelerator pedal.

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I've had four 3.5efi Autos since my last 3.9, but those speeds sound about right to me ... given the light throttle.

Thank you and best wishes to all.

Dear All. I am (unfortunately) back. After what I thought was a permanent fix to the automatic gearbox's problem with the kickdown cable positioned back into its slot I did about 500 km. And then. It happened. All forward gears are missing. Not in low range. Not in 1st. Or 2nd. Or 3rd. Not in Drive. None. Reverse is fine. Checked fluid level. Perfect, hence reverse is still working. What are your thoughts? Forward clutch kit? You'll read above on this thread that I have replaced the filter when I got the kickdown hooked up on the cam. Bad news?

Noiriht said:

Forward clutch kit?

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Sounds very much like it - IIRC, the "A" sprag clutch has reversed due to being worn out ... so, time for a rebuild - but there's more info on the ashcroft site....

Guessing ZF have a dealer in RSA ?

From Ashcroft's site:
My Autobox is now only able to select reverse. Why?
Your A clutch (forward drive) has failed and you will require a replacement autobox.
ZF4HP22 - Ashcroft Transmissions (ashcroft-transmissions.co.uk)

Probably wear to the friction plates in the clutch pack. (I think the sprag clutch inverting means it all still works but won't set off in 'D', you have to select '1' to pull away & then put it 'D' until you stop again. Ashcroft's site does mention this)

The wear can be accelerated by the kickdown cable being disconnected or incorrectly adjusted and there is also an issue with seals on the input shaft wearing. These look like metal rings round the shaft with stepped ends, best replaced with the teflon ones.
BMW E32 - ZF4HP22 4 - Speed automatic transmission rebuild. (masscom.net)

The 'A' clutch is the one at the front & isn't particularly difficult to remove but be sure to keep everything the way round it came out!
Having the LR factory manual is a big help.
Problem may be that the friction material will be all over and inside everything including the torque converter & the fluid cooler. It's a very fine dust & the cleaning needs to be spotless or it will just get washed into your nice replacement box. Best to replace the TC & it's recommended to replace the cooler & its line/hoses as well.

This is also worth a look, same gearbox with the exception of the very back end & output shaft which is different on the LR. Note he strips the box, not necessary just to do the A clutch.
Chris Cowdery Global Presence
He mentions JP Auto Transmission for parts & I had a few bits for mine from them - incl the teflon seals - when I sorted out all its oil leaks a few years ago. They were excellent but I don't know if they ship overseas. I measured the A clutch friction plates on mine & there was very little wear but it's only one of several clutch packs & there was a lot of the fine dust I mentioned earlier.

ETA I found putting things back on, esp the TC, was much easier when I used an engine crane to hang the box vertically.

Thank you for your detailed reply, Ratae. It is information sharing like this from very experienced guys like you that makes this forum such a great treasure of information!

I am now started the process of finding spares/ professional transmission workshop with skiled technicians. Importing is an option but with our weak currency in mind, the last option in practice.

I do not have enough confidence doing it myself, but with input like yours we can assist whoever I find. Best wishes.

Link to JP Auto Transmissions if you haven't already found it. Lots of exploded diagrams & part numbers.
www.jpat.co.uk/index.html

I have seen overhaul kits for the ZF advertised on the internet but I've no idea how much use they'd be.

Thank you indeed. I am taking the front drive shaft off tomorrow and will to her to a Land Rover workshop next week some 20 km from where I stay. They will then remove the gearbox and send it in to a workshop (specialising in automatic transmissions) in which this LR place has a lot of confidence in.

If you don't mind I'll share and ask for your opinion in what will come up.

Best wishes from SA.