Been having some issues with my pickup recently that I believe originate from the transmission.

1994 C1500 5.7 w/ 4L60E and 277k miles

1st one I noticed when it started getting cold a few months ago. The transmission wouldn't shift into OD until I had driven about 5 miles or more and was sufficiently warmed up.

2nd has me a bit worried because I've read a few other threads with the same symptoms. I am getting a pretty intense shudder while under slight power. Usually happens at highway speeds. 60-65mph and I give it a little gas to maintain speed but not enough for it to downshift. Shudder shudder shudder. It stops if I left off the gas or give it enough to downshift. I don't have a tach so I don't know what range it's happening in.

Thoughts from the braintrust? I am mechanically inclined but do not have the equipment to really tear into a transmission.

Thanks,

Tim

 

After reading some more threads this afternoon I am starting to think my torque converter is the issue. My first problem where I thought it wasn't shifting into OD until it warms up was wrong. It is in OD, it's just the torque converter is not locking up. All I am hearing in the cab is a drop in rpm after driving for 5 or so miles and thought it was the OD. Could the torque converter cause the shuddering under power?

Thoughts?...

 

#1..Transmission won't shift into lockup until the engine warms up..normal.
#2..There is nothing wrong with your converter. You've an engine miss and I'd look hard at the plug wires.


Oh, and I've been repairing GM automatics for over 50 years.


Allan

 

Not to highjack this thread... But,Allen in NE. Will a 4L80E direct bolt up to a 96 350 2WD that was a 4L60E originally? My truck has 304K on the original eng. and tranny. I building a 383 stroker and want a heavier/stronger trans.

 

Sure, it will bolt up.

The electronics are totally different between the two tho.

Allan

 

Hmmmm... That causes more questions than gives answers. While that's good that the tranny isn't the issues a miss worries me a bit. I changed the cap, rotor, plugs, wires and filter about 5k miles ago. I'll have to pull them this weekend and see what I can find.

Thanks Allan

 

I also have the same problem with my 1992 Scottsdale. Started when I had a new engine installed, The mechanic that installed the engine tried adjusting the cable from the throttle body to the transmission. Helped a bit but, but on the highway it will shudder on the downshift out of overdrive. Increasing the speed or decreasing the speed will make it stop shuddering. Please post if you find a remedy.
Thanks!