48RE Shift Problems

[ColoradoKing]

Have a problem that is getting worse: When accellerating the trans shifts up too soon. The more throttle, the worse it gets (ie: the sooner it shifts).



I have played with Edge settings, O/D lockout, Tow/Haul mode, Co-Pilot and PRXB on/off, and every combo of the above. The problem is negligible when cold and Tow/Haul dampens the effects when used.



Not sure if this is an electrical gremlin (Throttle position sensor, pressure solenoid governor, excess electrical noise due to all the boxes hooked to transmission wiring, a short, a broken pin on the PCM bus... ?), or it could be mechanical within the valve body or elsewhere.



Haven't found a similar problem yet, so would appreciate any TDR know-how advice, suggestions or SWAGs.



Many thanks!

 

[cerberusiam]

Any codes when you use the key trick?



The shift points are low on these transmissions anyway and when you add power it just gets worse.



Since you have an 05 the TV pressure is controlled by the TTVA motor which relies on speed and throttle position to set TV pressure. With low throttle opening and more speed the ECU sets TV pressure to shift faster becuase it thinks its behind. Thats one aspect.



The other is the gov pressure solenoid, its gets set by the same parameters. The comnbination tends to mess up the shifting.



Your problem sounds like TV pressure is not advancing fast enough and gov pressure is causing an early shift. (SWAG 1)



Couple things come to mind, pull the TTVA motor and advance the gear that drives the TV linkage one tooth and see if that helps. Replace gov solenoid as it may stuck open and not returning. FYI, Borg has a new solenoid that is better and DTT has a new GM one with the wiring correct for the Dodge, plus, the several aftermarket upgrades.



With extra power and the TTVA motor, a DTT Shift Enhanser is a good investment. Allows you to tune the TV pressure a bit more.

 

[ColoradoKing]

Cerberusiam,



No codes. Yet. I am driving very conservatively so as not to over-stress the drive components, especially the transmission.



I did read the threads and your comments on TTVA and GP Solenoid, but just wanted to get a gauge on whether this problem I had was connected in some way.



Many thanks for your wisdom. I'll order up some parts and let you know what I found out.

 

[ColoradoKing]

Turns out that it was the Co-Pilot. Pressures checked out OK. They did adjust the TTVA very slightly, but everything worked fine on the test bench. During the road test, it was discovered that if the Co-Pilot select arrows were scrolled, the TCC signal for lock-up was screwing the signal up for both TCC lock-up and shift points.



Of course, the symptoms were exactly what happened last summer, after I'd installed the Co-Pilot. I never did get them checked out because I must have re-adjusted the shift points and the problem disappeared.



I send an email to ATS (with the email stream from last year) to see what they'll do about it.



Will keep you posted.