I have a 2001 Duramax/Allison Chev. When it sets for 2 days or longer it will not back up right away, it takes about a minute of idling before I can move.
Iâ€™ve brought it to several Chevy dealerships, but no one can fix it. Do you have any ideas about this problem?
Hi there JimT,
Have they changed the NSBU (nuetral safety back up switch)? Are there any codes? Only a qualified Allison tech can check with a laptop and software. (I am sure your dealers have checked) There have been problems with the switches or even if your shift linkage is out of adjustment. Another cause could be a solenoid inside or a plugged external filter. I will ask the Allison engineers next time I call them and see if they have run into this problem but my guess would be a NSBU switch.Unfortunatly an Allison distributer can not do any warranty work on GMC or Chevy without being subcontracted by your GMC/Chevy dealer. Let me know if the switch has been changed. Thanks and have a great day!
As far as I know they haven't changed any switches (none on invoice and not told they had). They also didn't mention any codes. They told me twice that they updated the program, but that didn't work.
They now tell me a fix is being worked on and is about a month away. I really don't belive them!! The truck is now out of warrentee, but since the problem has been from the begining they are not charging me (at least so far)
I'll be traveling to New Hampshire soon and will bring your printed out re-ply to the selling dealer.
Thanks for your imput, if you do learn more please let me know.
It may be awhile before I check back (we'll be on the road in a week)
You bet I will forward any new info. if I get.By the way, did they check the dipstick calibration? Sometimes they are miss marked from the OEM and transmission fluid expands when warmed and you may just be low on fluid even though your dipstick says it is ok. Have a great and safe trip!
I hope you recieve this update. There is an Allison Service letter refering to your symptoms. It is SIL 29-1k2k-02 and describeswhat is wrong with your transmission. You need a new Lube regulator spring and new converter relief valve spring. here is the writing of description in the service letter (SIL). This resolves the loss of pump prime after startup that is sometimes experienced when the vehicle is not started for approximately 1 week. I really hope you get this update. Thanks - AllisonMan Oh yes, have a great day!