Question Transmission wont upshift?

Hi all, my wife has been telling me that sometimes when she is driving her excursion it fails to upshift, now i have tried for months to recreate the situation but cant.
So here is the deal she says that it keeps revving and wont upshift until she takes her foot off the throttle slightly, and this is really strange but she said it does it mostly when she is turning. The truck has 140k and is completely stock it is and 2001 4wd, the transmission has been serviced every 15K to 20K, and at about 100k i started doing the complete flush at the dealership. I installed a tranny temp gauge in 2003 in the pan and it still reads about the same as it always has. the highest it will get is 188* on a 108* day which is very common here in Vegas. Any thoughts or comments would be appreciated, i figure to just keep running it as i cant think of anything i can do from a preventative standpoint.

I know with my Truck it has a spot at 45mph where it wont upshift into 4th until I let off the accelerator a little bit. Kinda weird but sometimes its a good thing it wont upshift... like when I'm going up a rather steep hill

Travis

If this was an older transmission I would say that you needed to look at the Modulator valve or the vacuum line to it on the newer transmissions I haven't got a clue. Joe

yup, my spot is right at 40mph.

So this might be a common problem and might not be worth looking into anymore???

Might be the converter not locking up. When the tranny is below operating temp the converter will not lock up.

You scan for codes shift errors will show up.

i know this is going to sound really weird and unthinkable...i thought the guy at the local diesel performance shop was BSing me but my tranny did that a couple times with my wife and it was having some other problems. when i took it in i told the guy everything it was doing and he put a scanner on it and said that my ficm was going bad. and i said can you read for any codes or know what might be wrong with my tranny bc it wasnt wanting to shift at the right time. he said my ficm may have something to do with it....(scratched my head and pondered and said oooook) so i replaced my ficm....butter my ***** and call me a bisquit! tranny problems solved too!!

well typed all that for nothing....you are talking about a 7.3!!! (smh) lol

Update on this, i finally got this thing to not shift and it is just like my wife said::: Upon making a right turn while already rolling and accelerating slightly it is like the tranny slips as you apply pressure to the accelerator so i just kept mashing on the throttle and it revved more and then shifted so i dont want to say it slipped more so it kept revving but felt like slipping.
The reason i was driving it today was that i was trying to recreate her symptoms, and also i had mentioned to her that in my driving of it i noticed that there was a large delay when shifting from : to :R: , something that has not been there before. Anybody have thoughts on why it is now having a long delay when changing directions, and has this slipping/revving issue when you accelerate making a right hand turn. I am thinking something electronic or a detent ball that is in the valve body but i have very little tranny knowledge.
I never included the right hand thing in my original question because i thought she was making some of the symptoms up.
That will teach me to doubt her.

as always best regards to all.

You got me on the right turn stuff.

Delay reverse/drive could be the boost valve sticking.

When was the last flush and service?




Sent from my SGH-T959V using Tapatalk 2