Will shift kit help?

[mjgrantham2003]

Hello, I am new here and in search of advice regarding my 4T65E trans. I actually drive a Montana, but I find little help on other forums, and this one seems to have a lot of knowledge and activity regarding this trans. However I can't find an answer to my problem/question in existing threads. I want to know if the improvement in line pressure you would get from adding a shift kit would secondarily cause a more positive engagement/transfer of power at the torque converter due to increase in "line pressure". Mine just hit 250k miles and since I've owned it has always seemed to have a laggy/weak torque transfer. Not sure I'm explaining this right...the RPMs required to get the thing up and moving is higher than other vehicles I've owned, including my previous vehicle which was a Venture that had same motor and the 4T60E, which was super quick even @ nearly 200k miles. Along with the laggy, higher-than-normal RPMs on acceleration, the shifts occur at much higher RPMs than they should, and they are the slow, delayed shifts which sometimes then become hard. I am fully aware of the 1811 code and related issues. So would it be worth trying a shift kit? Could it help? I'd appreciate some expert insight. Thanks!

[JamesIvey24]

you can buy the spacers real cheap, or make your own.....but it sounds like you may have waited a bit late to try to extend the life.

[BrandonHall10]

Hello, I am new here and in search of advice regarding my 4T65E trans. I actually drive a Montana, but I find little help on other forums, and this one seems to have a lot of knowledge and activity regarding this trans. However I can't find an answer to my problem/question in existing threads. I want to know if the improvement in line pressure you would get from adding a shift kit would secondarily cause a more positive engagement/transfer of power at the torque converter due to increase in "line pressure". Mine just hit 250k miles and since I've owned it has always seemed to have a laggy/weak torque transfer. Not sure I'm explaining this right...the RPMs required to get the thing up and moving is higher than other vehicles I've owned, including my previous vehicle which was a Venture that had same motor and the 4T60E, which was super quick even @ nearly 200k miles. Along with the laggy, higher-than-normal RPMs on acceleration, the shifts occur at much higher RPMs than they should, and they are the slow, delayed shifts which sometimes then become hard. I am fully aware of the 1811 code and related issues. So would it be worth trying a shift kit? Could it help? I'd appreciate some expert insight. Thanks!

I know exactly what you're talking about. I went from a '98 Montana Transport (4t60e) to an '04 Silhouette (4t65e). The shift characteristics are so different, I thought something was wrong with the new van. Like you said, higher RPM shift, long shift time.... If you look at the actual tune, the shift times for the more modern vans are super long (over 0.4 seconds) compared to a much quicker 0.2 seconds or so of the older vans. Having said that, I did put a shift kit in the new van, and it helped a little but nothing major. I think it's just the way they are programmed/tuned. To give a softer, more gentle acceleration feel.

[mjgrantham2003]

I know exactly what you're talking about. I went from a '98 Montana Transport (4t60e) to an '04 Silhouette (4t65e). The shift characteristics are so different, I thought something was wrong with the new van. Like you said, higher RPM shift, long shift time.... If you look at the actual tune, the shift times for the more modern vans are super long (over 0.4 seconds) compared to a much quicker 0.2 seconds or so of the older vans. Having said that, I did put a shift kit in the new van, and it helped a little but nothing major. I think it's just the way they are programmed/tuned. To give a softer, more gentle acceleration feel.

I've wondered if the newer ones are tuned to be softer, but this one is definitely not right. Sometimes (more when cold) RPMs climb high and it sort of waits to shift as if it's struggling for something to happen that would initiate the shift, then it's a slow shift. I eventually get the hard shifting, but the delayed shifts can occur over and over, say for a half hour of stop and go driving before it goes to full line pressure. And shutting it off doesn't always make it go back to normal pressure. So a stuck PCS is likely cause here. Btw, I got the van w/ 229k and spent a year or so fixing it up. It also has no OD. I didn't know about the tranny problems when I bought it but I got it real cheap. I'd kinda like to try a shift kit, maybe even replace 4th hub and PCS, but at that point maybe rebuilding the valve body or a complete swap would be a better choice.

[BrandonHall10]

...a complete swap would be a better choice.

That's what I'm thinking. At 229K that thing has to be pretty much used up. Unless 99% are highway miles. Even then, that's a lot of use.

[mjgrantham2003]

Having said that, I did put a shift kit in the new van, and it helped a little but nothing major. I think it's just the way they are programmed/tuned.

What kind of shift kit did you use? What parts did you swap out? Also, besides a shift kit, can the PCM be reprogrammed to speed up shift timing?

[BrandonHall10]

What kind of shift kit did you use? What parts did you swap out? Also, besides a shift kit, can the PCM be reprogrammed to speed up shift timing?

Just the standard Trans-Go 4t65e kit. You can change the shift times in the PCM, but I'm not sure how much of a difference that will make overall. At 229K, there's going to be a TON of slop in the clutch packs. Especially if it's originally a factory build.