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'99 - '06 GM Truck Modifications
Transmission & Transfer Case
2003 GMC 1-2 shift issues
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<blockquote data-quote="knucklehead" data-source="post: 8104" data-attributes="member: 733"><p>When i got this vehicle a couple years ago, the 1-2 and 2-3 shifts were long and drawn out. i babied it for a while and then decided to rebuild it. the reverse input drum surface was a total mess where the band was so i replaced that and both sprags as hard part replacements. I also installed pinless accumulators in the 1-2 housing and forward housing, replaced the 1-2 accumulator valve line with the updated GM part, .490 boost valve, and installed the Transgo SK kit in the valve body, blocking off the 4th accumulator for a nice 4th gear apply. New TG separator plate drilled per TG instructions and a corvette (093) servo. I only have problems now with the 1-2 shift. Vehicle has 145k miles on it and had already been "rebuilt" once. It has 4 pinion planets in it for some reason - my guess is that whoever rebuilt it before pulled the 5 pinion planets out to sell on ebay (probably how I got my set for my other trans rebuild, lol!) Anyway, at part throttle (normal driving) the 1-2 shift is delayed and then shifts hard. all other shifts are nice, quick, and firm but not harsh. I currently have my pressure gauge hooked up to the test port. i don't have a lot of data yet to provide from the gauge due to trying to drive while watching the gauge - I watched the road, not the gauge, lol!. I bought rebuilt valve bodies for my previous rebuilds, but wanted to try my hand at it on this one. any suggestions? My guess is that whatever is causing this is also responsible for wearing out the reverse input drum. Any/all input is appreciated!!!</p></blockquote><p></p>
[QUOTE="knucklehead, post: 8104, member: 733"] When i got this vehicle a couple years ago, the 1-2 and 2-3 shifts were long and drawn out. i babied it for a while and then decided to rebuild it. the reverse input drum surface was a total mess where the band was so i replaced that and both sprags as hard part replacements. I also installed pinless accumulators in the 1-2 housing and forward housing, replaced the 1-2 accumulator valve line with the updated GM part, .490 boost valve, and installed the Transgo SK kit in the valve body, blocking off the 4th accumulator for a nice 4th gear apply. New TG separator plate drilled per TG instructions and a corvette (093) servo. I only have problems now with the 1-2 shift. Vehicle has 145k miles on it and had already been "rebuilt" once. It has 4 pinion planets in it for some reason - my guess is that whoever rebuilt it before pulled the 5 pinion planets out to sell on ebay (probably how I got my set for my other trans rebuild, lol!) Anyway, at part throttle (normal driving) the 1-2 shift is delayed and then shifts hard. all other shifts are nice, quick, and firm but not harsh. I currently have my pressure gauge hooked up to the test port. i don't have a lot of data yet to provide from the gauge due to trying to drive while watching the gauge - I watched the road, not the gauge, lol!. I bought rebuilt valve bodies for my previous rebuilds, but wanted to try my hand at it on this one. any suggestions? My guess is that whatever is causing this is also responsible for wearing out the reverse input drum. Any/all input is appreciated!!! [/QUOTE]
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'99 - '06 GM Truck Modifications
Transmission & Transfer Case
2003 GMC 1-2 shift issues
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