The other day I broke the handle off on my ATF dipstick and had to cover the fill tube with aluminum foil till a new stick comes in on Tuesday. Since covering the tube with a plastic bag then foil and zip tying so it's almost air tight and isn't going to fall off the transmission is shuttle shifting between 3rd and 3rd lock (OD off, around town driving under 50mph). Does the fill tube vent transmission pressure gas? And could this cause my shuttle shift? Or should I catch up on the lock/unlock topic?

I don't think it vents.

The cap is normally near air tight but haven't checked to see if o-ring or just cap ....

Shuttle shift won't have anything to do with this

Transmission will build a small amount of pressure from the heat expanding gases inside. But no fluid should be venting from the dipstick tube just a small amount of vapor and gases as the fluid heats and cools.

Agree shuttle shift isnt caused by that. I would suspect gov. pressure sensor, solinoid, and band adjustment

Shoot, tranny was just rebuilt in january, not even 3,000 miles on it since. Haven't had any issues since this. I believe they put a DNJ extreme solenoid in it, amsoil fluid (my mechanic said it lasts longer that other stuff, he runs it in his 5.9 and his dads 6.7). What next? Stop in to see the tranny guys?

On a side note, the tranny shifts so early when on light throttle, like at 1100 rpm, it will not hold 1st or 2nd, like in a parking lot taking turns it's in 3rd or 2nd gear dogging it at 15 mph. On decent throttle, it shifts at 1600-1800 and I've adjusted the linkage, it only effects the shift points when on throttle.

Tranny Build- Billet single disc rated for 500 HP (DPC), Raybestos Blues, upgraded planetary, stock input shaft, etc.

Can't tell if the TC is slipping either because the roads are so bad right now and I have "rough riding ranchos"

Sound like it needs some adjusting...

Time to go to builder

You can check AC noise, apps voltage and throttle linkage.

I pulled a code p0122 throttle position sensor low. Adjust the tps to the voltage set on the back of it?

I pulled a code p0122 throttle position sensor low. Adjust the tps to the voltage set on the back of it?

 

NO! Do not adjust the voltage! The voltage is only for the IVS of the APPS nothing more. I would run the diagnostics of the error code.

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/151-p0122-apps-sensor-signal-voltage-too-low

One thing I would look at is the trans fluid , if your Amsoil person is good they they did a good cross check , if not ....... you may have the wrong fluid and it will show erratic shifts too.

Thanks guys. Hopefully ill have time this weekend yo follow Michael's write up