48re headache
 

just built my 04 2500 tranny (only had 88k on it:td:) under normal accel it shifts fine but periodically if i put pedal to the metal @ 45mph it will jump back and forth between 2nd & 3rd or just hang in second and not shift at all. i've also noticed if i only slow to 30 or so and stomp it again it will do it repettively however if i come to a complete stop it will usually shift fine when i nail it again. used raybestos high energy clutches ,single clutch billet convertor, billet 4 ring accumulator piston, transgo shift kit ,new od & tq solenoid ,& gm style gov regulator with new sensor. tranny man said unhook battery cable and let it sit over nite then try again.:s:

check your electrical grounds

battery unhooked overnite to no avail still did it today. i backed off the tv cable a little and run new ground wire from battery to bolt in tranny bell housing. any other imput or ideas?

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still not fixed. seems to just hang in 2nd till i back off then it'll shift fine.:scare2:

What are the current TPS Voltages? Are they moving like normal or hanging in one location?

don't know voltages but just stumbled across competition diesel web site with current thread for exact problem and the guy has transgo shift kit like i do and he's being told that's the culprit.

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just thought about it but just before pulling tranny for rebuild i did check voltages and they seemed fine. smooth rise with no sudden jumps or hang ups. the reason for pulling was a hard early shift to od & tq lock up when towing heavy load. front band was shot which was evident before going in due to not being able to feel 1 2 shift and it wouldn't tighten up. only other issue we found internally was direct drive clutches and front plate was shot. hard shift issue seems to be gone its just when i stand on it empty playing around/pressure testing it (or just plan ol having fun:tu:) that i now have this issue.

spent time on phone with transgo with manual pressure gauge & snap on scanner through obd11 port on truck today. when he found out i had gm style gov pressure regulator he immediatly said that was problem that he had supposedly worked with suncoast on this same problem and they had determined the gm regulator was not putting out enough pressure to work properly at wot. spent more time on phone with different trans tech who is just as adamant that the transgo shift kit is the trouble and the gm style gov reg is the way to go. guess i'll try the old reg tommorow and see what happens.:s:

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fixed it today. problem was combo of shift kit with gm style gov regulator. gm only allows high 70's to low 90's(psi) when at wot and 48re needs solid 90psi to shift correctly at wot from 2 to 3. with scanner on you could watch it jump from 87 to 92 and tranny would shift back and forth in time with pressure change.the guys at transgo told me they had worked with suncoast on this problem and after talking with MYSTERYNC today he got me hooked up with suncoast tech guru who verified what transgo had told me yesterday. the solution is to either go back to stock solenoid which will actually generate up to 110psi or drill a .018 or .02 hole in end of gm solenoid. i chose to drill a.02 hole since i already had the solenoid &since they are supposed to be more durable and with the scanner hooked up went for test drive and it consistantly nailed 100psi every time @ 2 3 shift @ wot and worked flawless.many thanks to MYSTERNC and to ernie with suncoast.:jump::hellox:

Good news !

Im am going to close this as it appears to be fixed. You can reopen it if you need or want to.