Truck only moves in 4-Lo

[Sullijm1]

1990 4Runner, 3.0 V6, A340H trans

My truck is only moving under it's own power in 4-Lo. It will cycle through all the gears, but does so very roughly. When trying to move it slowly idling, it jerks around a little bit.

When in 2-Hi or 4-Hi, it feels like it tries to move, even shifts through the gears sometimes. However, it moves at literally 1 MPH, if that, and will not even try if it is met with the slightest grade.

When in 4-Lo, I can smell burning, hear what sounds like a turbine or a fan, and a strange whining noise.

I checked the fluid and changed it today. It is full and the filter had dirty oil before. But the oil change and filter cleaning did not fix it.

This truck is my only vehicle, but it is only a recreational vehicle. I have a 3.4L and a manual lined up for it, the work will get done when I leave for my first deployment. But until then, I don't want to spend more than $1,000 on a fix.

 

[Ahlem]

Let it idle a while and double check the transmission fluid level. My experience with automatic transmissions is that the fluid fairies drink the stuff and need more after a while. You might need to feed them several times. Once when I had the torque converter out of a different brand vehicle, I had to run through this several times and several heat cycles before it worked correctly. I believe there is a switch on your transfer case that might need a good looking at as well.

 

[fourwd1]

How many miles on it?
Have you checked to see if any Trans Error Codes have been set?
It's a procedure similar to checking CEL codes.
It may be that it is so worn and have so much slippage and the low range gearing is able to multiply what little output there is.