trans slips and the trans is fine, help

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Jul 20, 2013 | 03:10 PM

quigman

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From: tucson

trans slips and the trans is fine, help

Hey guys I have an 05 lq4 and am having trans problems that I believe are electrically oriented. First I will say the trans has 40,000 miles on it. It has been removed and tore down to reveal absolutely nothing wrong with it. The problem is when you drive with moderate throttle it works fine, but when you put your foot down the motor just revs and the truck goes no where. We put scanner on it that operated the trans manually with the scanner it seemed to work much better.
The trans worked when I first got the project running. I have put maybe 50 miles on the truck since built. Please help. There are no trouble codes present.

Last edited by quigman; Jul 20, 2013 at 05:54 PM.

Jul 21, 2013 | 10:35 AM

Bowtie316

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From: KC KS

What trans, what mods to motor, what tune changes???

Jul 21, 2013 | 01:52 PM

quigman

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From: tucson

Tran is the original 4l80E from the 6.0 lq4 from an 05 2500. The harness and computer are from Howell Engine development. The tune is a very basic high-po tune with no emmisions. The engine and trans are bone stock aside from headers and cold air intake. Sorry I don't know the specifics.

Jul 21, 2013 | 05:55 PM

Bowtie316

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From: KC KS

Beats me, I would start by checking the line pressure.

Any chance a tire is spinning?

Jul 21, 2013 | 07:53 PM

quigman

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From: tucson

The line pressures check out fine. We did update the hydraulics when we had it out to check things. We hooked up a scanner that can manually work the trans by adjusting pressures and shift points etc. The truck ran better. It seems the problem lies in the electronics. I checked all the grounds and they were fine. Amy ideas.