recently my gf's blazer started acting up. the problem is the torque converter will go in and out of lockup spuratically. I took it to a trans shop and they took it for a ride with the scanner hooked up and found that it was going in and out of lockup and he said the temp was a little high at 180. now the truck wasnt acting up as bad as it has been when they drove it. the scanner did say that it was happening 35% of the time. there is no stored codes or anything. also I noticed when driving it when this happens that if you accelerate a little it will lock up and stay locked up until you have to slow down and reaccelerate. the trans shop said from what he sees it could be a torque converter itself or a pump issue since it was running a little hot. Ive been searching the net and reading alot on the issue but havent found anything on exactly what this one is doing. Ive had people tell me that it could be as simple as a tps or maf sensor causing this all the way to it being the converter, pump, tcc solinoid. also sice she bought the truck it makes a sound like a bolt rattling in a can that changes with engine rpm for the life of me I have not figured it out but it does sound like its coming from the tranny. any help would be greatly appreciated. Im not against throwing a tranny in but I hate to do that and it end up being a tps or maf, how can I test these to make sure they are working properly?

 

If you let off the gas, it will unlock the torque converter. If you hit the brake, it will unlock the torque converter. I generaly keep it in D3 and manually shift it to D4 once I get up above 45 MPH to keep the converter from going nuts and keeping my Blazer from "running up" on people.

If it's shuttering on slight load on the highway, the clutch in the TC is mostt likely bad. If it's acting like a three-year-old playing with a light switch, It could be the TCC circuit, or anything in that system of triggers.

That rattle-can sound is the Cat Converter. Been there, done that. Rattle at idle and coming back down from revving the engine - or all the time for that matter. Horrible sounding!

http://www.youtube.com/watch?v=cOAZuLV0N0E

Hope that helps you out!

FYI - My transmission was built by Extreme Overdrive in Jacksonville, Florida. He handed me back the keys and stated, "You can go where you want; you can tow what you want." Best money I ever spent - but don't spend it unless you have to!

 

the rattle isnt the cat, I replaced the whole exaust thinking it was the cat and it didnt change anything. I actually think its something came apart in the converter thats making theat noise. I like the three year old analogy thats what its doing but you can get it to stay locked up by slightly accelerating. if it is in the tcc circuit where should I start looking? thats what a friend of mine said that it could be the tps or maf not reading right how do I check these? thanks for the response. also it doesnt shutter at highway speeds but it does shutter on takeoff the trans shop said that the shutter on takeoff felt like a bad ujoint.

 

FCC is up front of the valve body. You'll need to drop the pan.

And grab the drive shaft "Monkey-Style" and use a pry bar to check for ANY movement out of normal to check the u-joints.

To check the other sensors, a Haynes manual will give you the needed values and specs for those.

Hope that helps you out!

 

im having the same problem. im going to try the tps. Also my ABS is disengaged (fuse pulled because of the common wheel bearing sensor). My OD does not disengage when i hit the brakes either. If its not the TPS then im going to replace some solenoids in the trans.

just found this site: http://www.twincharlotte.com/transmi...r-Charlotte-NC

might be some help?

 

I just replaced the cruise control release switch on my '94 Blazer. That's what tells the TCC to unlock. I would check the switch and make sure it's operating correctly before doing any more extensive troubleshooting. It should be attached to the brake pedal lever up under the dash.