Need Help Please - 4L60e Tranny Slipping After New Converter, Filter Seals

Hi All, I previously posted about needing help finding a converter. I have had the engine rebuilt, new seals and filter on the tranny and changed from a yank 3600 stall to a Circle D 2600-2800 converter (thanks for the offer chvy=power but I had already ordered). I just got the break in procedure done on the engine and was ready to test drive, but when I put it in gear, the engine just free revs. Every once in while I can get it to move slightly then nothing, just free revs. This is in a 2002 GMC Sierra Short box two wheel drive. The tranny is apparently out of a 2003 chevy van and was working fine in my truck before taking it out.

Does anyone have any ideas on what to do or what it could be?

Thanks.

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Originally Posted by AZ02

Hi All, I previously posted about needing help finding a converter. I have had the engine rebuilt, new seals and filter on the tranny and changed from a yank 3600 stall to a Circle D 2600-2800 converter (thanks for the offer chvy=power but I had already ordered). I just got the break in procedure done on the engine and was ready to test drive, but when I put it in gear, the engine just free revs. Every once in while I can get it to move slightly then nothing, just free revs. This is in a 2002 GMC Sierra Short box two wheel drive. The tranny is apparently out of a 2003 chevy van and was working fine in my truck before taking it out.

Does anyone have any ideas on what to do or what it could be?

Thanks.

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Low fluid. Filter is wrong ie. u ut a shallow filter in a deep pan. Stall not seated correctly jumping outa pump

Thanks for the info. I think I will be having it towed to a transmission shop to get it figured out. I am at the end of my understanding of transmissions. I will mention these possibilities to the tranny shop when I drop it off. Hope it something simple...

Sounds kinda like converter isnt in all the way

I will discuss this with the shop as a possibility. I appreciate the response!

Update: After the tranny shop removed the tranny (not easy since the previous owner welded the exhaust pipes to the headers and all the way back!)they found the torque converter had been chewed up at the end of the end of the pump shaft. At first they blamed my converter but then after putting in a factory stall and new pump, they discovered it would not mate back up. They involved the machinist who rebuilt the engine and discovered the wrong crankshaft (early 99-00) had been installed. It is longer than the crank that was taken out by about a 1/2" at the rear flange. After much debate, they found a concaved flexplate that was from a different application, had it neutral balanced. This solved the issue and allowed everything to mate up. To their credit, they all accepted responsibility without any reservation. Making a long story as short as possible I drove the truck home and... the reverse clutches went out , speedometer was bouncing all over the place above 45 mph, ABS light was on and the starter was hanging up. Tranny was removed again and completely rebuilt, starter shimmed, new speed sensor. Picked it up yesterday. The tranny works great, engine runs smooth and strong. However, starter is hanging up slightly upon release, speedometer was working great and no ABS light...then they both acted up as before...then both went back to acting fine...now there is major leak at the pan gasket and another at the bellhousing. Frustrating, but hopefully getting close to having everything working... Just thought you all might want to hear...the rest of the story..... This has been one incredible learning curve for sure.

It turns out the cooling line was leaking. Replaced it and all is dry outside. Drip from bellhousing was residual from install. Still have ABS/Speedometer issue so will need to figure that out. It is great to have it running again!

I wonder if the starter hanging up is from the offset flex plate they used?

They used a thicker starter shim and solved the issue. Works perfect now. I would guess the offset doesn't exactly position the same as the original setup, but it seems to have lined the flexplate up about the same distance from the block as the stock setup. Thankfully it has all come together in good shape....