turbo246

alrite, well im getttin pretty irritated with this truck knowing something just isnt right when its locked out of overdrive, or in overdrive gear. well after reading my shop book i determined when i lock it out of overdrive it is shifting 1,2,3 then the convertor clutch is NOT engaging like its supposed it, and the book says its controlled by the PCM to a solenoid but the book stops there with information. And i have overdrive, but it does not stay locked at all, but it will shift into it. how do i go about this, i really dont want to mess with the PCM, but if i can find the wires that control the solenoid for the convertor clutch, i think that is my issue, and is the solenoid in the tranny? i have a video i just put on youtube of me taking off from a stop with the overdrive OFF any info is appreciated, I was offered over 10K for this truck and i paid 3k, BUT i ahve to fix this in order for them to buy it. i will post the video in a seccond, youtube says ITS PROCESSING


heres the video http://www.youtube.com/watch?v=od8FMzZ3CIo

dozer12216

Are you sure it's not going into 3rd lockup directly in OD off mode? Normally it shifts are: one to two, two to three, lockup, and 4th lockup. In unlock you should be able to get RPM to rise faster than vehicle for a second.
The inhibits to Lockup are:coolant temp, engine RPM, vehicle speed, throttle position, manifold vacaum, and RPM speed sensor on extension.
At the transmission 8 way connector the OR/BK controls the TC solenoid by providing the PCM grounding. Red wire is power from control relay. Hook a voltmeter to that wire and if voltage goes low on the road, it is elecrically shifting into lockup. The pcm grounds the solenoid to achieve lockup after all parameters are met.

NKYGuy28

My truck seems to shift the same as yours does in the vid. How does one know when the TC is locked? I have never noticed anything. When is it suppose to lock up?

bsp

It sounds like @ around 29 mph it locked up and then unlocked ( slight rpm drop then rpm rise) I may be wrong. Try it again and when it shifts to 3rd give it more fuel and see if it stays locked up and then let off slightly to see if it unlocks. I think that would be normal. My truck will do the same under light to moderate throttle but when I'm "on it" a little with od out then @ about 50 -55 hit the od button it will go into od locked. Under normal driving going through the gears it will lock up in 3rd, unlock to shift into od, then lock back up. I put a noise filter on mine before I had the tranny rebuilt and solved my locking - unlocking issue in od, I also had a flakey apps that gave me some fits............Brad

hic316

I am not sure, but on my 99, I thought the converter only locks up in overdrive. You can test to see if the converter is locking by putting the truck into overdrive, keeping your foot on the accelerator, and lightly tap the brake, if the TC is locked it will unlock, when the brake is pressed, and your rpm's will rise. I also have a TC lock up switch and the converter will lock and only shift up from second. 1st doesn't allow for lock up.