So i got the shocks and exhaust done. went to take it for a first test run since i got it. went up my drive way and it started shaking really bad and sounding like it was going to stall. I bleed the fuel lines before hand because it had no fuel in it, also did the fuel filter prior to that. Got about 30 feet from where it started shaking and it stalled in drive. restarted it put it in 2nd, it stalled, put it in first and it shook bad, got it back into the drive way. Reverse seems to work fine, but the 3 forward gears make it want to stall and i dont know why. Its a 86 C6 6.9l by the way. any ideas fellas.

 

sounds like the torque converter just died.

 

Torque converter???

 

transmits engine power threw the trans to the drive wheels. the best way i can describe it, is it acts like a the clutch in a manual trans. prevents the engine from stalling when the vehicle is in gear and not moving.

 

ahh I see, are the difficult for a back yard mechanic to fix/replace?

 

I wouldn't see a torque converter causing this just in forward gears, and "usually" when a torque converter dies, it just free spins.


But when they do go bad, shouldn't it mess up all gears?

 

Something might be sticking in the valve body, it may be trying to engage the forward clutch and the low reverse clutch at the same time.

There is a vacuum modulator on the rightside of the trans it has a vacuum line going to it, pull the line and see if there is trans fluid in it, if it is replace the modulator.

And if it just had exhaust work the line may have accidently gotten pulled off.

How long did you run it after bleeding the system?

 

Sounds like possibly the clutches are toast and seized the drum(s). Here's a link to where I got all my parts, and they are very knowledgable. C4 C6 Performance Transmission from PATC, C6 Transmission

 

let it run about 15 minutes. i bleed the lines till it was a constant stream of fuel.

 

Let it run today. Did something odd. didnt seem to want to find the forward gear except 1D. And the gear indicator seemed to be off to. Reverse again worked fine, but the gear indicator was off.

 

Might want to try adjusting the shifter, of at least inspecting the linkage.

 

Could that be the cause of my issues, the shifter not putting the truck all the way in gear?

 

Yes make sure its all tight, that would explain why your pointer doesnt line up.

 

Wonder if the kick down lever is stuck? A lot of the C-6's don't have the rod attached anymore. Playing around the exhaust, the lever could be stuck in the kickdown position. That would be rear ward.....right? Having a foggy brain cramp at the moment!

 

Rear ward yes, but that would only cause highest RPM shifts between gears.