4T65e rough shifts

[digitaloutsider]

I'm posting this on here because it applies to plenty of W-bodies too. Today, while I was in traffic the Montana started acting like a reprogrammed PCM with the line pressure shot way up. This feels JUST like my friend Brandon's GTP (his transmission line pressure is jacked up in the PCM). When the transmission goes to shift, it does it VERY quickly and crisply. To be honest with you, I don't mind it all too much.. I'm just worried it's some other bigger problem. It doesn't act strange in any other manner, and the transmission is a remanufactured one that's only 15,000 miles old. No SES lights, nothing. WTF could be the problem?

[sl3196]

Mine kinda does that sometimes too. I could drive it for 6 hours straight on the highway and no rough shifts and when I get to town it starts shifting rough. Doesn't happen all the time but still weird. That is with performance shift off too.

[digitaloutsider]

Drove it again to get some of my sister's stuff since she's going to be living with us temporarily. Car shifted beautifully.. Go figure. BTW, Dan, I'd leave Performance Shift on all the time. The quicker the shifts, the less wear and tear on the cluches.

[88Regal Limited]

BTW, Dan, I'd leave Performance Shift on all the time. The quicker the shifts, the less wear and tear on the cluches.

 

But more line pressure will also do damage to the tranny.

[digitaloutsider]

Tell that to every ClubGP member who has their car in PS mode all the time. It doesn't do shit. Most guys have their transmission line pressure jacked up full time. Doesn't hurt the transmission a bit.

[pwmin]

i wouldnt run it in ps mode all the time. i certainly wouldnt leave my sister's 4.0 cherokee in ps mode.

[sl3196]

I don't leave mine on cause I like getting better mileage. With it on it revs higher before shifting under normal throttle. Only put it on for racing hehe.

[R Dubya]

there is a pressure control solenoid in the valve asm of those trannys that is fairly easy to replace and usually causes hard shifting when its bad.. I think it runs around $50-$80. I look one up almost every day for one of those trannys. The gasket kit runs a little less than $10, just make sure you replace the fluid you use. I can get a pn# if you need it, but any dealer could tell ya.