1996 KZN185 Autobox loss of drive

[pejo]

problem with the auto box on a '96 3rd gen'.
If its started from cold it pulls away ok and will drive up our local steep lane as normal, as soon as it gets hot its all on to move on the flat.
Have checked the oil level and that looks ok at the correct level and checked with hot gearbox.
Seems to be a bit of a whirring noise from the bottom area of the box on tickover that I don't think was there before
can anyone suggest what to check through

regards pejo

[charvell]

change the oil mate

[Vagrant No2]

Wot colour is the auto fluid ? If brown or even black you could have worn bands in the gearbox . If nice red colour it could be valve block problem or gearbox ECU ?

[BUSHWHACKER]

Did you check the fluid level with the engine running?

[pejo]

yes checked with the engine running and the level was ok.
The colour of the oil is now a shade of brown the red it should be.
Quoted today £1250 plus vat for a box rebuild,by Martin Lowes in Barnsley certainly not a cheap fix if it has to be done.
Will drop the gearbox sump plate and see there is any bits in it later this week
thanks for replies pejo

[BUSHWHACKER]

It won't need replacing, it'll be a fluid or electrical control (ECU) problem. These transmissions are bomb proof.

[Alamo]

Got exactly same problem with my 3.0L 2nd gen. Pulls like a train when cold but loses a hell of a lot of it once warmed up. Also smells hot on the outside of the truck after a decent run but I've been putting that down to a coating of waxoyl. ATF has been changed twice now in 6 months and the level is bang on the full mark when warm and running. Cooling system has been flushed through, new water pump, stat and rad cap. Gears seem to change up and down ok and I've also tried swapping the ECU. I've had it looked at by 3 or 4 local mechanics, the Auto Gearbox Company in Rochdale and the Engine Company (Stevo) in Stockport.....but still the same.

I'll be keeping a close eye on this thread and let you know if I come up with anything.

Alan

[pejo]

Changed the ATF oil and about 5ltrs came out, refilled with new but when it was hot same symptoms no drive and a buzzing whirring noise from the box.

Called into the transmission rebuilders who said from my description the box wanted overhaulin and also the transmission oil cooler could be leaking water into the gearbox oil .
cost for this was £1450 for the box and £150 for a seperate oil cooler both plus vat.

Today I have taken the gearbox sump off and removed the oil filter .
Washed the filter out in petrol and refitted and filled up with new oil again.

Have driven it for 10miles and its ok ,no loss of drive and the buzzing noise has gone.

Think the filter was blocked and the buzzing noise was lack of oil supply to the torque converter.
Will see if a new filter is available tomorrow
regards pejo

[BUSHWHACKER]

Changed the ATF oil and about 5ltrs came out, refilled with new but when it was hot same symptoms no drive and a buzzing whirring noise from the box.

Called into the transmission rebuilders who said from my description the box wanted overhaulin and also the transmission oil cooler could be leaking water into the gearbox oil .
cost for this was £1450 for the box and £150 for a seperate oil cooler both plus vat.

Today I have taken the gearbox sump off and removed the oil filter .
Washed the filter out in petrol and refitted and filled up with new oil again.

Have driven it for 10miles and its ok ,no loss of drive and the buzzing noise has gone.

Think the filter was blocked and the buzzing noise was lack of oil supply to the torque converter.
Will see if a new filter is available tomorrow
regards pejo

Guess you won't trust that shop again!

It's just a strainer rather than a filter, now you've cleaned it it'll last several years, no need to replace it.

[Alamo]

Sounds like you've got it sorted.

I might treat my truck to something similar, but seem to recall reading something somewhere about removal of the filter/strainer from the gearbox being a ball-ache of a job to do. Did you find that to be the case?

Alan

[pejo]

Takes about an hour.
Remove the bolts from the sump pan and carefully split the joint.
The dipstick tube has a joint in the middle ,give it a pull and the sump comes away.
If its same as mine you will be surprised at the muck left in the sump after draining the oil. Don't lose the 4 magnets from the sump.
No gasket on the face , used silicon liquid gasket .
hope thats all it is on yours
Pejo

[pejo]

Forgot to mention the strainer.
Remove the 4 bolts that holds the strainer to the valvebox , and wash in petrol till its clean then bolt back on .....easy

pejo