Auto gearchange all over the place!

I have had a 1990 diesel with automatic gearbox for 3 years now and have had the car serviced professionally regularly. However, it seems to me to be getting more sluggish and the gearchange to the automatic gearbox is either really sluggish to change as you get faster and then at higher highway speeds when cruising it starts to "hunt" for a lower gear. I am sure the oil level is OK and I had the oil entirely changed not long ago as well. I see there are quite a few people complaining of frustrating auto gearboxes so maybee there is some sort of factory fault with this? Otherwise the car is great!

Have you had the box serviced by a auto box professional it may need the bands adjusted

Its possible the kickdown cable may need adjusting slightly....note position of ferrule on cable and only adjust within 3mm...its sensitive.
When maladusted the gearchanges literally go bananas.
Also check the atm oil...does it smell burnt or is it very dirty?....this would indicate wear...a flush and replace can rejuvinate things sometimes...

Philip, Did you manage to fix this problem? I have had what sounds like the same issue on my 1993 SC and havent yet got around to fixing it....

Maybe you're looking at the wrong area for your problem. You said the gearbox oil is fresh, so presumably any burning of the clutches/bands would have been recognised at the oil change..................

If the engine is not in a good state of tune, then you will be applying more throttle to compensate for the lack of power. Using more throttle "tells" the autobox to use different change up/kickdown points.

Possible problem areas?

Engine tune, assuming it's diesel, worn injectors/pump/fuel filters/air filters choked/tight valve clearances/low cylinder compression...............etc.

What I'm getting at is, make sure the engine's in tip top shape and the 'box will follow on - it's very throttle/load dependant.

Oh, also make sure your brakes aren't binding!

Good luck

Philip D wrote:

I have had a 1990 diesel with automatic gearbox ...... ..... and the gearchange ..... it starts to "hunt" for a lower gear. I...............

Hi Phillip,
I guess you worked this out long ago but for anyone else's info I had a 1990 2.8 SC "executive' with pretty much the same highly stressful issue. I had both main solenoids in the gearbox replaced resulting in zero improvement. Then had the gearbox fully reconditioned, again with zero improvement! Both jobs by gearbox specialist - so it should have been fixed, right?
I suspect it was a computer problem as that works out the changes or an unresolved relay /electrical connector problem.
I feel the problem had a significant contribution to a subsequent cracked head (replaced with new one) then a stuffed crank a month later. I gave up and went to a whole new KZTE van so I've still got the 2.8L engine with a new head, injectors and glow plugs and the old head too if any locals are keen. (I've just decided I'll head down the part it out track. I'm keeping the g/box, reduction box & a bunch of other bits as spares).
I've just joined the forum so I'll eventually figure out if locals are in here and if so I'll put up an add in a more appropriate area.

Cheers for now