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Discussion Starter #1
Hey, I am having some issues with transmission. I am getting a p0756 code and have high line pressure while in 2nd gear. Line pressure at idle in 2nd gear is 180psi, all other gears are pretty well bang on spec. I have already changed the b solenoid. What could cause line pressure to be high on only one clothe one clutch pack? Also dpf is deleted and am running Dirty Diesel custom tunes.
 

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Discussion Starter #3
Yeah that's in manual 2. Seems to jump in and out of second when shifting from first and has no over drive.
 

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Does it engage gear in manual 2? It doesn’t look like o/d clutch is applying by pressure. If it won’t engage manual 2 you have a mechanical issue. Possible stuck clutch piston.
 

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Discussion Starter #6
I was reading the atsg manual again trying to find something and it says a certainsensor failure may cause higher line pressure blah blah blah. So is it possiblenthe pressure switch for over drive clutch isn't opening and causing the pcm to send more amperage to the solenoid thus causing my over pressure?
 

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Discussion Starter #8
Right, now that you mention it I remember seeing upgrade plugs for that. Darn so much for that idea. And the only thingncontrolling line pressure for each clutch pack is the shift solenoid right? There is a main relief but ifnthat was sticking I would have near the same results in all gears correct? So if there was a short to power in the b solenoid wiring it could cause it to have higher than normal pressure but it would throw a code would it not?
 

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Yes the shift solenoid controls the pressure to the clutch. If there is an issue with the wiring it should throw a code for the wiring. I believe that code is for a mechanically stuck solenoid, meaning it commanded the solenoid on but did not move.

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Discussion Starter #11
I changed my tune from street tune to race tune and 2nd gear line pressure is normal. No over drive but shifts better from first to second. I'm thinking it's possibly a tuning issue.
 
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