4L60 transmission problems...
 

Okay fellas I've got a 1994 chevy k1500 with the 4L60 and last few nights I've noticed my truck has been shifting differently and finally last night it started slipping really bad in OD and mildly bad in Drive. So today I pulled the pan and drained the fluid and changed the filter (after breaking 2 bolts off) and got it all put back together. Wasn't any big chunks of metal in the pan. But there were chunks of somethin in the fluid but they weren't magnetic. Any idea of whats going on or whats going to happen soon? And haven't got a chance to test drive it yet.

Material could be fiber from one or many discs in the 3-4 clutch pack. If 3-4 clutch pack has failed....I believe you will get slip since it is applied in both 3rd and 4th (OD).
The 4L60 was not the strongest trans in the GM fleet. Can't remember the exact year, but believe it was 2002, GM did do an upgrade in hardness to the reaction sunshell and I believe they hardened the shafts too, but still not to where they should be to make the trans a very strong trans.

if your talking about that shiny little fine particals then that,s coming off the clutches from heat ! i saw those particals more then once and it did not hurt the transmission any !

if you do end up doing any work to the tranny, install a hi-flow torque converter.
I made sure the shop that did my tranny did. along with go through everything.

I think if my transmission ever goes out again, I will try to install a manual 1st, or a 4L80E 2nd.

If rebuilding the trans, get a HD rebuild kit from a reputable firm. Or get a rapture 4L trans and never worry about it again.
And was it "particles" or "chunks"? As bandit noted, small particles are no problem and pretty standard, but "chunks" are not normal.

If the transmission is slipping, you've wasted a filter/oil change. The damage is already done and the transmission has to come out.

Allan

There were both particles and chunks. I know the particles were normal but the chunks weren't magnectic and the particles were.

I agree with f5fstop sounds like 3rd and 4th gear clutch disks are bad. No sense in wasting anymore time or money on it. Time to rebuild it. The fluid change should have come way before you noticed any slippage. A nice firm shift kit and a good high flow converter would be a very good investment.

When I had a hi flow TQ installed, I had a couple leaks at the cooling coil from the increased pressure.
No big deal, but just a heads up you could have a few minor leaks.

Took it to a tranny shop and its shot. Guy said the small particles are part of the clutches and the bigger chunk was part of the drum. Gonna cost me 1800 for a beefy rebuild.