Transmission issue

Florida.man352

New member
Jul 6, 2021
3
0
1
So about a month ago, my truck started to have transmission issues. The main symptom are ranger selector is missing, whenever I shift into rev or drive it shifts extremely hard, it’s stuck in limp mode, and the check engine light is on. Whenever I do have it in drive it takes a little bit to actually get the truck going. I know nothing mechanically is wrong with the transmission. I have replaced the NSBU and TCM. And nothing had gotten better. My next step is either the shift linkage or pressure valve ??
 

zakkb787

<that’s not me...
Sep 29, 2014
2,340
52
48
Granite Falls NC
Please post the year of your truck, any mods you have done, and what codes you have from a GOOD scanner. Without this no one is going to be able to help
 

Florida.man352

New member
Jul 6, 2021
3
0
1
Please post the year of your truck, any mods you have done, and what codes you have from a GOOD scanner. Without this no one is going to be able to help
It’s a 2004 lb7, it has a banks iq tuner, banks cold air intake, five in mbrp turbo back exhaust with 8in tip, both cat conversations on oil and tranny, and I just replaced the tcm with dans diesel products
 

zakkb787

<that’s not me...
Sep 29, 2014
2,340
52
48
Granite Falls NC
Straight from the obd site:


The PCM or TCM uses the transmission range sensor, also called the inhibitor switch, to determine the position of the shift lever. If it receives signals that indicate two different gear positions at the same time for more than 30 seconds P0708 will be set. If this occurs twice in a row the check engine light will come on and the transmission will be commanded into "fail-safe" or "limp-home" mode.

Just for giggles, have you tried removing the banks system and resetting the system with your batteries? Also, how old are your batteries? It’s an extremely long shot but these trucks are EXTREMELY finicky with voltages and so weird things when low. Hopefully Mike chimes back in with some better insight for you. Not much of a trans guy myself.

edit: are you sure your new NSBU is good?

Read more at: https://www.obd-codes.com/p0708
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