Problems with transmission shifting.....Please Help!!
06-29-2006, 08:40 PM
#1
Staging Lane
Thread Starter
iTrader: (1)
Join Date: Sep 2004
Location: Springfield, MO
Posts: 87
Likes: 0
Received 0 Likes
on
0 Posts
Problems with transmission shifting.....Please Help!! First off I have searched and found many threads on this topic and all of them just say the transmission is bad, and since we know this transmission is not they didn't really help a lot.
So i'll try to keep this short and sweet.
Basically I had a 4l60E built about 2 months ago, it was rated at about 875 HP. We installed it and had been tuning on it when we ran into a problem. During WOT the transmission will not shift from 2-3, it will go until either it hits the rev limiter or I let out of the throttle about 5%-15% and it will shift crisp. Today I had it hooked up on a shaeffer shifter, we were able to tell that it was not the transmission that had the problem but something with tuning or other electrical. When the transmission was told to shift with the shaeffer shifter it would do it every time it was told. We tested it from 5500 rpm up to ~6400 rpm.
We have adjusted the tables with my HP tuner and nothing seems to work.
Currently the shift rpm is set at 6250 for a WOT 2-3 shift. We have also played with the shift properties MPH. I need some more ideas on what the problem could be? Any suggestions would help.
A little about the
-Full suspension
-Moser 9"
-3800 TCI stall
-Heads and Cam
-150 NX wet kit that I can't use until this problem gets fixed
I can have a log file tomorrow and I also have the flash file so any of you would like to see the tuning adjustments that have been made. Just let me know.
Thanks
So i'll try to keep this short and sweet.
Basically I had a 4l60E built about 2 months ago, it was rated at about 875 HP. We installed it and had been tuning on it when we ran into a problem. During WOT the transmission will not shift from 2-3, it will go until either it hits the rev limiter or I let out of the throttle about 5%-15% and it will shift crisp. Today I had it hooked up on a shaeffer shifter, we were able to tell that it was not the transmission that had the problem but something with tuning or other electrical. When the transmission was told to shift with the shaeffer shifter it would do it every time it was told. We tested it from 5500 rpm up to ~6400 rpm.
We have adjusted the tables with my HP tuner and nothing seems to work.
Currently the shift rpm is set at 6250 for a WOT 2-3 shift. We have also played with the shift properties MPH. I need some more ideas on what the problem could be? Any suggestions would help.
A little about the
-Full suspension
-Moser 9"
-3800 TCI stall
-Heads and Cam
-150 NX wet kit that I can't use until this problem gets fixed
I can have a log file tomorrow and I also have the flash file so any of you would like to see the tuning adjustments that have been made. Just let me know.
Thanks
06-29-2006, 09:08 PM
#2
On The Tree
iTrader: (5)
Join Date: Aug 2005
Location: South Carolina
Posts: 110
Likes: 0
Received 0 Likes
on
0 Posts
This may not be any help, but I had the same problem with mine. I had the engine rebuilt and was going to deal with that problem later, but after the engine rebuild it never did it again. Ive drivin about 10k miles now and shifted perfect every time.
05-31-2007, 12:37 PM
#5
Try setting all commanded shift MPH tables to 0 (ZERO) to force it to shift by RPM.
I had this same issue on a tranny and it was the snap ring that held the 2-3 clutch pack in (tranny was modfied to carry extra clutches/steels and the new retainer was flimsy).
Even after repaired, that tranny never shifted when commanded, the RPM numbers were totally fudged. Try this to rule out some PCM and output/noid issues as well... set the MPH to 0 and the shift RPM to 4500-5000 RPMs and see if you get a shift before the limiter. Take care to properly scale back the NON WOT TABLES FOR PART THROTTLE SHIFTING ALSO. IF you don't have the commanded shift time set low, it will "adapt" itself back out. Set those times to less than a half second (I beleive thats the cut point for adaption).
Take care to not modify any pressure related tables.
Log and see if the shift is being commanded and ignored; that should only leave the shift noid.
I had this same issue on a tranny and it was the snap ring that held the 2-3 clutch pack in (tranny was modfied to carry extra clutches/steels and the new retainer was flimsy).
Even after repaired, that tranny never shifted when commanded, the RPM numbers were totally fudged. Try this to rule out some PCM and output/noid issues as well... set the MPH to 0 and the shift RPM to 4500-5000 RPMs and see if you get a shift before the limiter. Take care to properly scale back the NON WOT TABLES FOR PART THROTTLE SHIFTING ALSO. IF you don't have the commanded shift time set low, it will "adapt" itself back out. Set those times to less than a half second (I beleive thats the cut point for adaption).
Take care to not modify any pressure related tables.
Log and see if the shift is being commanded and ignored; that should only leave the shift noid.
06-02-2007, 08:07 AM
#6
10 Second Club
iTrader: (15)
Join Date: Feb 2005
Location: fort worth, tx
Posts: 611
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Frost
Try setting all commanded shift MPH tables to 0 (ZERO) to force it to shift by RPM.
I had this same issue on a tranny and it was the snap ring that held the 2-3 clutch pack in (tranny was modfied to carry extra clutches/steels and the new retainer was flimsy).
Even after repaired, that tranny never shifted when commanded, the RPM numbers were totally fudged. Try this to rule out some PCM and output/noid issues as well... set the MPH to 0 and the shift RPM to 4500-5000 RPMs and see if you get a shift before the limiter. Take care to properly scale back the NON WOT TABLES FOR PART THROTTLE SHIFTING ALSO. IF you don't have the commanded shift time set low, it will "adapt" itself back out. Set those times to less than a half second (I beleive thats the cut point for adaption).
Take care to not modify any pressure related tables.
Log and see if the shift is being commanded and ignored; that should only leave the shift noid.
I had this same issue on a tranny and it was the snap ring that held the 2-3 clutch pack in (tranny was modfied to carry extra clutches/steels and the new retainer was flimsy).
Even after repaired, that tranny never shifted when commanded, the RPM numbers were totally fudged. Try this to rule out some PCM and output/noid issues as well... set the MPH to 0 and the shift RPM to 4500-5000 RPMs and see if you get a shift before the limiter. Take care to properly scale back the NON WOT TABLES FOR PART THROTTLE SHIFTING ALSO. IF you don't have the commanded shift time set low, it will "adapt" itself back out. Set those times to less than a half second (I beleive thats the cut point for adaption).
Take care to not modify any pressure related tables.
Log and see if the shift is being commanded and ignored; that should only leave the shift noid.
hmm.
sounds like a good test for the probs that have come up for me over the past 2wks..
gonna try it today before i yank this unit out and throw it off a cliff.