Automatic transmission

[Paul]

As there is definatly something amiss with the auto box on mine the investigations will begin.
Firstly i will do a fluid change to see whats happens, but the local dealer tells me there is no filter inside the box, is this correct? He says they have never changed one. Also, are there any recommendations for the fluid different from standard? And the capacity?
I am keen to get it all out so any tips for getting more than a normal drain? I have read the thread on the valve body replacement allowing lots more to come out when loosening the bolts so will try this. Any drains on the Torque Converter?

Will post results in case i have to move onto a rebuild of TC and box.

 

[Jon Wildsmith]

AFAIK there is just a mesh screen, same as on the 80 series. I would just do several changes a short distance apart, any extra you can get out by loosening the valve body etc must be quite a small % of total volume. A 20l tub of Fuchs or similar would be a good start and only switch to expensive stuff if the problem goes away? What are your symptoms?

 

[Paul]

Most of the time everything is ok.

First problem shows up when going slow at the bottom of a hill (like on a corner) then accelerating a reasonable amount to go up, the kickdown is quite a thud, as if you had dumped the clutch in a manual.

Then, on the motorway, when going in and out of overdrive to overtake etc (not using the button on the gearstick, just the gas pedal) the change can be quite rough. Not sure if this is normal as it is an overdrive.

I have read up on the stalling problem where it is difficult to stop or slow down, but this seems ok, the only issue on this front is when creeping forward for a parking space etc and the AC kicks in the raised engine speed can be noticable in road speed.

Generally though, the box does not feel as smooth as i would expect from a truck like this, i have not owned many autos but they were all a lot smoother.

Cheers

 

[Jon Wildsmith]

They're not the smoothest engine / gearbox combination especially if you're comparing to say a saloon car auto but even so you shouldn't be getting a thud. Assuming it's not just slack in the drive train and a fluid change doesn't fix it then maybe the SLT solenoid is failing.

 

[Paul]

Cheers for that Jon, i have had a look through the service history and cant see a box oil change but there is quite a big folder, always Toyota Serviced and dont know if they actually change it as dealers seem to think it does not need doing frequently.

SLT? can that be done in place?

 

[Jon Wildsmith]

SLT? can that be done in place?

AFAIK yes, it's just one of the solenoids bolted to the underside of the valve body. It controls the hydraulic pressure applied to the clutch plates and is driven by a PWM signal from the ECT whereas the other solenoids in there are either on or off. It replaces a mechanical valve that was cable driven from the injection pump throttle assembly on the 80 series. As you can imagine the hydraulic pressure on the clutches varies during gear change, like dipping the clutch on a manual but if the valve were starting to fail you could get a very harsh gear change under power.

 

[Paul]

Cheers Jon

Does the extreme valve body from Wholesale Transmissions have that part on or do you use the old one?

 

[Jon Wildsmith]

You use your existing solenoids.