Help. I have the 1996 Discovery Diesel 2.5, 300tdi with Auto tanny.
my problem is in normal driving the geabox refuses to up shift, just rev's away,the down shifts are fine and normal.
If I floor the pedel to kick down she will rev, accellerate and then at the appropriate point up shift and as long as I'm powering on she will up shift, all-be-it late as would be expected.

In order to drive and get her to up shift I have to power on and then back off the pedel, at which point she upshifts. Then gently power on again till I get to about (or past the point) where the next up shift would come; I then back off the power and the tranny up shifts again.

On these auto boxes is there an electronic control or is it all 'proper mechanical' things that controll shift points?

Any ideas greatly accepted.
Cheers,
Dave.

 

How many miles on the tranny, how often do you service it?
Could be the shift cable is stretched too ling and needs adjustment, the valves in the valve body are sticking or the governor is hanging up.
Good luck, let us know what you find.

 

It's got a 100,000 miles on and until 70,000(when we bought it) had full dealer services. I had the local garage do a gear box service at 75,000 just (along with a full fluids change of diffs etc) but this was as far as I know just filter and oil change

She has never had a tow hitch fitted. And has never been offroaded.

I read my Haines manual, but it says very little about the gearbox, well nothing really.

Would you suggest I start with the cable or the governer, is this similar to the Chevy TH350 in the way it opperates
Thanks,
Dave.

 

I would start with the cable, making sure it is properly adjusted, the rest is internal.
Mike

 

Thanks, I unhooked the cable from the throttle braket see-saw mechanism and WOW what a difference. With the kick down disconected she shifts like a Rolls Royce, a magic carpet ride. Obviuosly the adjustment needs to be looked at.
I tried to balance it with a sensible kick down position but no matter how far I adjusted the kickdown cable I couldn't get a decent drive (or up change).

I think the coarse adjustment on the throttle cable side may need to be looked at before I can set the adjustment on the kickdown cable.

I've played with THM350/400 and 700R4 on my import trucks in the past, Checy Blazer, K15s and C10 but never had anything as fiddly as a home grown Disco. I'll have a better look this weekend when I have time and light.
Thanks again,
Dave.