03 48RE 1st to Second shifting problem

[SWithrow]

Last night I WOT(rolling at 35-40mph) to get onto the interstate and after sitting for a hour I headed back home only to notice that the truck will not shift into 2nd until I take it to red line and let off the accelerator a couple of times then it goes into 2nd and shifts all the way to OD/lockup, and I have tried to manually shift and it will not shift.

No problems downshifting, no noise while driving and when it shifts it is still nice and firm, fluid is at full and nice and red. I have a TransGo shift kit, Goerend Triple disk, GM Governor Pressure Solenoid and about 110k on trans.

I have noticed in the past few months if I accelerate too fast from a dead stop that the transmission would stay in 1st until I let off the pedal slightly then it would shift, normal acceleration it would shift fine. Any help would be greatly appreciated.

 

[cerberusiam]

Do you have amnaul 2nd gear?

Have to get a gauge on it but it is likely the pressure transducer gone bad if you cannot find a mechanical issue.

 

[fox]

I'm helping a friend fix an 06 that is doing this. His Gov. pressure are less than 1/2 of the spec. He doesn't want to change the solinoid and sensor again, so I'n not sure how to help him.

 

[cerberusiam]

GM solenoid if he doesn't have and a new transducer is the only way to fix it unless you want to try a constant pressure VB from Goerends.

 

[SWithrow]

When taking off from a stop i have to get it up to 3k rpm then let off the throttle them back onto the throttle before it goes into 2nd and then it shifts fine. Once at speed if I shift down to 3, 2 it works fine

Do you have amnaul 2nd gear?

Have to get a gauge on it but it is likely the pressure transducer gone bad if you cannot find a mechanical issue.

 

[cerberusiam]

Easier thing to do to see if it works is replace the output shaft speed sensor. If it flat lines low and does not rise it will cause a gear hang. If it quites completely it will hold the gear for around 5 seconds then shift.

 

[rscurtis]

Since you have an '03, check the position and operation of the TV cable.

 

[JJPage]

Since you have an '03, check the position and operation of the TV cable.

I was thinking along these lines, as I had a similar situation after a dyno run, truck would not shift out of 1st until red line or if I played with it by letting off the throttle.

Have you checked front band adjustment torque?

It could be the TV cable, but usually that affects all shift points, not just 1st to 2nd. The first thing I would do is change out trans fluid, to possibly flush any debris from the governor solenoid, then re-check operation. If that solves the issues, great, if not then the next thing I would do would be a new APPS from Timbo, that's what cured my problem.

Cerb's suggestion of the output speed shaft sensor could also cause, and would be the easiest and cheapest exercise, but after a WOT action seemed to cause this I would be sceptical but not surprised.

If you have to adjust the TV cable after the APPS replacement, here's how, read entire thread, pay close attention to post's #8 & #9 https://www.turbodieselregister.com...rky-transmission&highlight=jerky+transmission

Here's A PDF from BD http://www.dieselperformance.com/productManual/Dodge_Transmission_Instructions1.pdf

Good Luck, let us know, Jess

 

[SWithrow]

In the process of checking the TV cable I discovered that the truck rolls while in park. This will be the second band gone bad, I hope it is just the strut. I will dive into it later today.

 

[fox]

If it isn't going into park, it has nothing to do with the bands.

 

[rscurtis]

Fox is correct. Either the shift cable is broken or OOA, or you lost the parking pawl.

 

[SWithrow]

The cable is fine, it shifts the selector on trans in every postion. A few thousand miles ago I had the same issue with park position not holding and discovered that the front band had broke, replaced it and park was functioning.

 

[cerberusiam]

Front band has nothing to do with park. However, if the front band breaks it drops the strut on to the linkage that engages the parking pawl and jams it. You will not have manual second if the band linkage falls out. It will downshift to manual second and you will have no gear while the engine will just rev. You indicated you could get 2nd manual, is that still true?

 

[SWithrow]

I dropped the pan today and found a piece of metal (I believe to be the OD retaining ring about half inch long) so I will be pulling the VB and OD unit tomorrow. I didn’t want to drive it until I figure out where the metal came from. Years ago I had the same size piece of metal in my old 47re that came from the OD unit.

Front band has nothing to do with park. However, if the front band breaks it drops the strut on to the linkage that engages the parking pawl and jams it. You will not have manual second if the band linkage falls out. It will downshift to manual second and you will have no gear while the engine will just rev. You indicated you could get 2nd manual, is that still true?

 

[cerberusiam]

Sanp ring piece is likely from the OD unit, that is the typical source.

 

[SWithrow]

****Update****

I dropped the pan & valve body and the band anchor fell out. The band has a crack where the anchor rest, so I will be pulling the trans this week and replacing the band and will install a new od retaining ring. Thanks for all of the insight and suggestions.

 

[JJPage]

Sorry... but glad you found the problem.

 

[SWithrow]

***2nd Update***

Okay, I am getting it done slow but never the less all said it has cost me less than $60:-laf including filter and fluid to fix the trans. I Replaced the bad front band on the trans and pulled the od unit off and removed the broken wave ring (5 different pieces), put the trans back together and should have it installed nlt Saturday.

 

[SWithrow]

Repair & Install Complete

Would have posted sooner but the wife knocked a glass of soda onto my laptop and killed it! (Trans was easier to fix).

The truck now shifts but that is under moderate acceleration, if I take off slow it won't shift into 2nd. Could the TV cable cause this?

 

[cerberusiam]

TV cable adjustment, gov pressure transducer\solenoid, output shaft speed sensor. Any or all can cause the hang shift in first gear.