98 4l60e wide open not wanting to shift third
The last 4L60E I worked on pulled real good in first and second, third would slip bad, it eventually stopped shifting into third. When I got it apart the forward clutches were fried, the fwd apply piston seal was blown out also. The owner had me do all kinds of bs to it, he wasted a lot of money before I talked him into doing it right.
If you search enough you will find that this complaint comes up often. Some people say to disconnect the wire harness to the trans so it defults to max line pressure and stays in third, they say if it holds like this then it likely not the clutches but an electrical issue. Thats not true because it also defaults max line pressure to all the clutches and even bad ones will hold until they're completly gone.
If it was low on fluid my guess is that someone had the pan off and cleaned it, changed the filter and maybe other things only to find it didn't help. Usually you can break the filter open and find clutch chunks, but if it's been done recently maybe not.
The last 4L60E I worked on pulled real good in first and second, third would slip bad, it eventually stopped shifting into third. When I got it apart the forward clutches were fried, the fwd apply piston seal was blown out also. The owner had me do all kinds of bs to it, he wasted a lot of money before I talked him into doing it right.
If you search enough you will find that this complaint comes up often. Some people say to disconnect the wire harness to the trans so it defults to max line pressure and stays in third, they say if it holds like this then it likely not the clutches but an electrical issue. Thats not true because it also defaults max line pressure to all the clutches and even bad ones will hold until they're completly gone.
If it was low on fluid my guess is that someone had the pan off and cleaned it, changed the filter and maybe other things only to find it didn't help. Usually you can break the filter open and find clutch chunks, but if it's been done recently maybe not.
The last one I worked on was for a guys daily driver tahoe. I was doing odd jobs on his collection of cars, he drove me nuts with this one because his buddy at the trans shop said do this, do that, he spent a lot of money with sensors and bullshit. His rans guy friend never said to break the filter open, the pan was pretty clean. There was clutch chunks in the filter. It would catch third sometimes, especially if the tps was disconnected.
I was surprised to find 3-4 not really burned up, it was forward. Why it ran and shifted 1-2 great I don't know.
I guess it's just the way I do things. If you need it to be reliable just take it out and go through it, you had it two weeks. The cost of a gasket set just to tear it down and reassemble it is less than one towing bill.
Last edited by Jays_SSZ28; Jan 30, 2018 at 07:58 PM.


