Had the Impala out tonight and it started to shift soft. By The time I got it home I had no forward gears. Reverse works fine. I had to back it down the street to get it into the garage. Tell me what it could be. Tranny fluid is not burnt and is full. Any ideas? It is a built 4L60E. I can't complain I have gotten over 2 years out of it and over 200 trips at the strip in the 4400 lb pig.
HVY SS

 

This is an easy one...Your aluminum forward piston is cracked. Very common problem in earlier 4L60E's. This is why we offer a steel piston upgrade.

Frank
CPT

 

Frank,
If you are still up call me. 859-398-9933.
Frank HVY SS

 

Nine minutes. Nice one, Frank! This is why if I ever own a 4L60E car, the first thing I'm doing is shipping it to you!

 

I pulled the pan and the fluid is clean. BUT I did find some metal pieces in the pan stuck to the magnet and in the front of the pan. I am running a GM deep pan with a pan magnet. This can't be good. I was hoping they were aluminum pieces from the piston but no they are metalic.
HVY SS Frank

 

You may not see any aluminum. Usually, it's a pretty clean break. I just tried to call you, but got your voice mail.

Frank
CPT

 

if the forward piston breaks it wont cause aluminum in pan. it cracks and pressure blows past piston and seals. if lost forward either that happened or sprag blew. check d1 or d2 if moves the sprag blew.

 

I think Frank is right. There is no movement in any forward gear D1, D2, D3, OD. Reverse works great. But not much fun riding around in reverse all the time. This a good time to send my Yank 3500 back and have it gone through.
HVY SS