ZF Auto Box

[Old Warthog]

Got an 89 RRC 3.5 EFI a couple of months ago.  It had been converted to a twin carb, due to problems with the ECU by the previous owner.  Its been running pretty well, a couple of 300 mile trips and a bit of gentle green laning.  The autobox performed ok in high and low ratio.

However, on Saturday, the box was refusing to change up at the normal points.  In fact its drives as though its in permanent kick down.  It also changes down at the same points - good if you like chest bruising!

Anybody got any ideas?

Looking at previous threads on the forum, it would seem that the only thing I can do is change the fluid and filter, which I will do on Saturday.

Haynes is totally unhelpful regarding ZF boxes - basically take it to a specialist.

This is a real bummer, 'cos I thought that I had finally found a green oval product, that didn't suffer terminal tinworm, had no injector problems or really weird untraceable electrical faults!!  I new it was too good to last

Cheers

Keith

[clbarclay]

£ times the price and about twice thickness, the official manual has a pages of auto box diagnosis :) and I was given one by a neighbour  :D

Anyway less of the gloting over the 'book of lies'. A quick look through and we get

Sympton
Upshifts, downshifts and kickdown shifts at incorrect road speeds

Check throttle kick down cable adjustment
And/or
Carry out maniline pressure check

If pressure is normal it could be the governor valve sticking

If pressure is incorrect it could be either incorrect throttle vlave adjustment or primary regulator sticking.



As for what the pressure should be and how to check it, willl let you know when I find it.

Found it, not surprisingly you will need a suitable guage tha will read 0 to 300 PSI and hose/adaptor to fit the transmission :roll: At idle pressure should be 100PSI give or take 5PSI and should rise up to 150PSI at 2000 rpm, again give or take 5PSI.

[clbarclay]

Just checking the maintenance schedules and it says auto box filter and oil to be changed every 24000 miles

[Old Warthog]

Thanks for the info guys.  I'll check the linkage when I do the oil change on Saturday.  The pressure testing I think is just a "leetle" bit beyond my resources :?

Luckily I don't have to use it, as I've now got yet another toy to run around in, this one with a 4 litre engine.  If my carbon footprint gets any bigger, I'll have to move to China :twisted:

Thats 9.5 litres between three petrol vehicles - I knew I should have invested in Shell :lol:

[Coastcard]

Agree with above regarding kickdown cable. Worth checking that there even is one!! I have tried to source twin SU kickdown brackets etc. and seem very hard to find!

If you have Stroms which were fitted to RR as OEM then hopefully all will be OK.

[Old Warthog]

Back to the drawing board.  Neither the fluid and filter change, nor alteration of the linkage cable setting made any difference   Now to start saving pennies to get an autobox specialist to look at it.  

Methinks the other things I had planned will be on the back burner for a while

Thanks for everybody's help

Keith