Trans running hot

[crash02]

I noticed that resistor on mine, but I don't recall seeing it on the FSM drawings. IIRC I back tracked it once and discovered that it is a bleed resistor to drain voltage in the brake sensor wires once the voltage feed is opened (removed, switch off) from the brake to TCU wire. If that resistor is bad I think it causes TC lock, unlock issues. I never found the resistor value marked on mine, nor listed in the FSM, so that is great data to have!!!! Might be worth a stick note!!!

here is the thread where I found it. Post #31
http://www.naxja.org/forum/showthread.php?t=1028593&page=3

 

[bigalpha]

FWIW, I drove the truck to work this morning and the trans temp never exceeded 160*.

I will be able to test it at higher speeds and check the TC unlock as well.

 

[bigalpha]

Ok, so I had the truck down for a while for maintenance and I hardly drove it. So now I'm back to this. I did drive it recently on a 2hr roundtrip adventure and the temp never got to 220*F. I'd say it maxed around 190-200*. In town, it sits around 160-170*.

After I swapped in the 96 booster, the pedal is at the correct height and the brake lights work. I checked the switch that's up on the pedal and this is what I found:

Switch overview (you can see my brake light switch with the blue/pink wires going to it, too):


Tip of the plunger on the switch from the side:


So the plunger is not pushed in at any time, as there's a minimum of 1/4" space between the plunger and the pedal assy at rest (not pushing the pedal).

From the thread MoFo referenced:

The circuit is of a strange design. With the brake pedal at rest, this switch is actuated and provides a ground to the TCU inupt when the pedal is NOT pressed, holding the input to the TCU at 0 volts. There is a pull-up resistor at this input, which provides a 12v signal to the TCU when the pedal is pressed.

So I'm to assume the pedal should be pushing the plunger IN while at rest (not pushing on the brake at all). So I need to unplug the wires and such and screw this in until it's pushed in?

 

[bigalpha]

Alright, so I went ahead and adjusted this switch. I think it was wildly out of whack do to the 96 booster swap (aluminum spacer).

Now, the TC definitely locks up and definitely unlocks. Problem is, that it jolts when it locks/unlocks.

At the time I had the trans fluid cooler installed, I don't think that the TC was locking up. Is it possible the fluid is low because of this and it's causing the jolting?

 

[Ecomike]

I would check the fluid level and the throttle cable adjustment on the throttle to transmission cable, as it seems to have some control of fluid pressure.

 

[bigalpha]

Ok, I'll check the fluid level. I'm not sure about the cable adjustment, though.

Is it weird it only started shifting poorly after fixing the TC lock up?

 

[bigalpha]

Fluid is correct level and color/smell.