Disco V8 auto box upshift hanging back 2nd to 3rd to 4th

Jan 29, 2006 5 Replies
J

Hi all,



Fix one thing and another problem bites you! Disco had a bit of a missfire so I changed plugs, leads, rotor, cap etc and she runs beautifully.



Immediately after this I went for a test drive. Changes nicely from 1st to second. Oi! wheres 3rd? I had to go up to 3.5th rpm to coax a change to 3th and then to 4th, not suitable for suburban driving!. All gearchanging was perfect before the ignition revamp.



So I figured I must have pulled off a vacuum tube, a cable or an electrical lead when I changed the plugs, leads etc. I cant see any fuses allocated to the transmission. Ive had a thorough check but all seems in order. AT fluid also at correct level.



A very harsh upchange to 3rd or 4th can be encouraged by almost releasing the throttle completly, and the box is very keen to change down, loves staying in second. 1st to 2nd seems as per normal



You can imaging what this does to fuel consumption!



Any ideas most welcome, thanks in advace.



LR Discovery 1997 3.9 V8


Vote
Twitter Facebook LinkedIn
B

There are no fuses, it's all mechanical. Check the setting and routeing of the kickdown cable coming from the throttle linkage near the no. 7 spark plug, it's possible you've disturbed it whilst doing the plugs. Badger.

Vote
Twitter Facebook LinkedIn
A

On or around Sun, 29 Jan 2006 11:22:09 +0000 (UTC), "Badger" enlightened us thusly:

Bet the cable outer is unseated from the adjuster, effectively making the cable about 1/2" short.

BTDT.

Mind, it don't half go well with a bit more kickdown - My procedure was to adjust the kickdown cable so that with the pedal mashed into the carpet (use a broomhandle or suchlike to wedge it there for adjustment) the kickdown cable is fully pulled out. Note that it's a mistake on the ZF to adjust it any tighter than that, so in practice, with the pedal mashed, you check the cable for a fraction more movement. Don't use the end of the kickdown travel as a throttle stop as it can bend things.

Vote
Twitter Facebook LinkedIn
J

Thanks for your logical thinking! Turns out the kickdown cable was pulled up from its seating on the gearbox, just a tad. I owe you beers when your Downunder. Take care

Vote
Twitter Facebook LinkedIn
J

Thanks for your logical thinking! Turns out the kickdown cable was pulled up from its seating on the gearbox, just a tad. I owe you guys beers when your Downunder. Take care

Vote
Twitter Facebook LinkedIn
A

On or around Tue, 31 Jan 2006 21:53:34 +1300, "Jac" enlightened us thusly:

hehe. BTDT,GTTS.

meanwhile, it's worth checking 2 things: a) when you floor the pedal, the throttle actually opens fully (adjust throttle cable if required) and b) check the kickdown cable adjustment.

certainly in the case of 3.5 autos, kickdown adjustment makes a lot of difference to the performance. The ZFs I've had the converter stalls at about 1800 ERPM, at which point, the engine isn't actually perfomring all that well. Could be mine were all knackered, of course. But getting the kickdown right made it more prone to use lower gears and get past the bogging down effect.

It's probably less of a problem on the 3.9. I can't find the peak torque figures at the moment, but I bet they're at more than 1800 RPM, even on the

3.9
Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required