Last Monday. Lost the transmission(4L60) in my 2004 Silverado Z71. Had it rebuilt at a local company. Got it back tonight. Was charged a load of money. Got home. And noticed at low speeds a grinding noise. I know it's not my wheel bearings or alignment. Anything possible wrong with the trans? Should I take it back in? Or try something else. They replaced solenoids, TC, and a complete rebuilt kit. The truck does drive totally different with this new transmission and does shift fairly hard. But not bad. Any info helps. Thanks

 

Welcome to the forum...
Did they replace the Ujoints, if they reused the old ones they could be the problem....
you might try shifting into neutral while rolling and see if the sound changes or goes away...
Do you hear it in reverse, at all speeds, might also try manually shift through gear range...

 

take it back ASAP and tell them about your grinding noise. The noise will have to be isolated to determine where its coming from.


The hard shifting could be from not resetting the transmission adaptive settings. If the hard shifting does not correct itself in 2 or 3 days of driving its not the adaptive settings.


IMO getting a GM rebuilt certa trans (rebuilt in a factory) in most cases is better than a trans shop rebuild.

 

Thank you. And it only happens at slow speeds. Below 15. They did reuse UJoints. It does happen in reverse. It's hard for me to pinpoint it from being inside it. But I have it narrowed down to the front end. My first thought was the transmission. But thinking now. I had the truck towed. It does have a RCD long arm suspension lift. He chained it to the front crossmember. The weirdest thing is. I started hearing it at a stop. But it slowly goes away once stopped.

The hard shift is only first to second. The rest are smooth as butter. If it doesn't get better. I will return it.

 

Hard shift has gotten better. Grinding noise now comes when in park, and when turning. Also new problem. Push button 4wheel is showing in Neutral???

 

you have a transfer case encoder motor problem. That is what the grind noise is. The motor is not fully moving into position.


if you were to unplug and remove the encoder motor and move the shift nut with a wrench...I bet the noise will be gone.


The good part is; your trans is ok.