merry Christmas everyone ! so after getting scammed on the first replacement trans I purchased a 2nd one and had it installed now truck shifts ok 1-3 but once I hit 4th gear ( 45 mph ) it feels strange and starts acting up . sluggish acceleration accompanied by a strange shifting up and down . I never experienced this with original trans and also noticed I'm commonly now at 2,300 rpms where as the original was normal cruising between 1,800-2,100 rpms . if I apply heavy foot work to the peddle it will accelerate and keep climbing through the gears but never had to do this before . I did not perform the install due to 20 degree temps outside and did find out the trans was 7qts short when it was returned to me . I filled to spec and truck engages reverse and drive smoothly . I was leaning towards the pressure transducer so pulled it and found they reused the pressure transducer from my bad trans and it was covered in shavings ( the shop was terrible and im looking into what my next steps will be but need to sort my truck out )
I disconnected the pressure sensor and test drove it did feel better not perfect but better so im leaning towards ordering a new sensor but any other feedback & direction would be appreciated .

 

Disconnecting the transducer puts the trans into max line pressure mode.

You need a quick learn performed to reset the clutch volume indexes (CVIs). Without the procedure, it takes a long time of driving for the TCM to re-learn the appropriate values. Meanwhile, the TCM is commanding the clutches to engage with an inappropriate amount of hydraulic pressure.

 

At the moment I’ve ordered a New pressure sensor, which will be here tomorrow. I do have the ability to take it to a dealership and have the relearn done. It’s about a 40 minute drive from me will that damage the transmission? I almost was under the impression that it was the converter, but I am seeing it lock and unlock on my very basic scanner that gives me live readings. I can see the pressure index on the scanner though. I don’t know if they’re accurate. Is there anywhere that I can get the pressure index ranges so I can look in real time and diagnose if they are out of synch ?

 

Dealer can do it, sure. A larger well equipped auto shop could also probably do it, the higher end scan tools have the quick learn function the DRBIII (dealer tool) has.

Any readings you see won't mean much right now. Nobody can tell you if it's safe to drive that far. If I was going to, I'd probably disconnect the pressure sensor to max out the line pressure and keep it out of overdrive.

 

ok I was worried I would cause damage by driving without it hooked up and was only to quickly test to see if infact a noticeable difference was detected. So sensor disconnected and OD off got it ! Thank you ! Now if I do the relearn and the issue remains any ideas what I’d be dealing with just so my bases are covered ?

 

so I disconnected the sensor and it intialy felt better with the OD off but then noticed some strange bumping and shifts is this to be expected ?

 

With the sensor disconnected it won't modulate line pressure when shifting. Harsh shifting is expected. The goal is to minimize slippage.

 

ok I got a line booster mod would that help to prevent slippage until I can get it scanned I have places I need to go but living in a semi ritual area makes tat problematic to say the least