no forward gears

patterson54321

New member
Aug 28, 2014
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hey everyone I got a 2003 Duramax and I have no forward gears it goes into gear but it slips through the whole gears but I have full reverse. I had a code for incorrect 5th geae but that was from before. Then i checked again this morning and had a vehicle speed sensor a ? P0500. Other then that i get no codes. I tranny flushed it, checked inside valve body for any debris etc. Changed the nsbu. I have no idea why i cant get a full forward gesr. Seems strange allllll the forward gears would slip, and that it would not go into a limp mode ?any help would be awsome ! Thanka !
 

patterson54321

New member
Aug 28, 2014
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Oh i forgot to add this is a used tranny with 120k on it, cause i blew my stock one apart a week ago when the torque let go. And i only drove this one for two days then i was pulling out and gave her some juice. And it just slipped
 

thunder550

Active member
Apr 2, 2013
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Phoenix, AZ
Fix that speed sensor error first. I'm not 100% sure but I think the trans may default to 3rd gear if it doesn't get a speed signal since it doesn't know how fast you're going.

What did the replacement trans come out of? Are you sure it's the exact same as the one you took out?
 

patterson54321

New member
Aug 28, 2014
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Okay so its a mechanical problem for sure. Any idea where to start inside ? Gonna drop it off at a buddys thats built a couple trannys. But hes never heard of this issue exactly lol
 

Bustedknuckles

Honey Badger
Sep 25, 2010
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Hagerstown MD
Okay so its a mechanical problem for sure. Any idea where to start inside ? Gonna drop it off at a buddys thats built a couple trannys. But hes never heard of this issue exactly lol
Might be the transfer case actually. I had a buddy buy a truck super cheap and it just needed a transfer case rebuild.
 

patterson54321

New member
Aug 28, 2014
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Thats so weird how they just totally blew apart. 0 metal in tranny. And i didnt even abuse it, stupid weak tranny. I need a turbo 400 lol!
 

patterson54321

New member
Aug 28, 2014
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All 3 used trannys around 130km on em. Have not been able to handle my big settin on chip, alwyas incorrect 5th gesr. But its just an edge. Coukd it be that speed sensor ?i cant go above 140 unless im on a tow setting