Alright, before I begin, I want to stress that I understand the frustration associated with people posting threads on a topic already discussed. I've searched and searched and yet to have find a situation that matches my dilemma. Here's my problem:
I have a 98 Blazer with 160k. My transmission feels very strong and shifts perfect from 1st gear all the way through overdrive. Once in overdrive however, cruising on a level surface stays fine but once I encounter a gradual to moderate incline and give it only soft acceleration (not enough to drop down to 3rd, staying in overdrive) the trans starts to slip. The tach bounces up and down a few hundred rpm's. Once I give it more throttle and the trans engages 3rd gear, it comes right out of it and holds strong. My gut feeling on this is that it's the torque converter since the trans itself doesn't seem to be slipping. I'm praying that somebody reads this and knows EXACTLY what I'm describing. A coworker/friend of mine mentioned that these have a torque converter solenoid that tends to go bad and could cause this problem. You have no idea how much I'll appreciate some help with this issue and once again, I apologize if I'm reopening a topic that's been tapped somewhere deep in the files of this forum. Thank you to all who respond to this with advice!

 

well part of your overdrive is that the blazer locks up the converter. and once its locked up it drops your rpm's a couple of hundred or so. when you are giving it a little bit of throttle the first thing that its going to do is un-lock the converter before it downshifts. it will only downshift if you open the throttle enough...thats when the extra wire on your throttle plate is for, its the throttle position sensor which tells the transmission when to shift.

 

Okay that makes sense. So does it sound like a tps or a more serious issue with the torque converter? Or even worse, a problem with the trans?

 

I'm really really hoping that someone has experienced this exact problem firsthand and knows precisely what is causing it.

 

tps??
im not familiar with that.....

anyway. how fast does the tach bounce in between rpm's? is it changing a few times a second or does it jump up and stay there for a little bit and then come back down?

 

Throttle position sensor. And it bounces quickly. Doesn't stay up and then come back down.

 

right before i clicked on the tread, it finally hit me what TPS stood for. a little brain fade i guess.

anyway. if its bouncing quick like you are saying, you could have a solenoid going out. and check your brake pedal switch. i was doing some research and i read that if your brake pedal switch isnt adjusted right it lock and unlock the TC rapidly.

 

Thank you for the help! I'm just gonna try the solenoid first and with any luck that'll be it. I got lucky when I fixed my 4wd, so hopefully this situation plays out the same way

 

good luck with it...i hope that its a simple fix.