The allison shifts hard the first time it goes from 1st to 2nd gear after that its fine. It only happens after its been sitting for a while, more than 6 hours. Ive tried different tunes and nothing helps. Please help thanks

mine does the same every morning for the first start. I've noticed that if I let it idle for a few it's not so bad.

mine does the same every morning for the first start. I've noticed that if I let it idle for a few it's not so bad.


Ditto!

When I purchased mine in October, I was told the Allison needs to idle anywhere from 30 seconds to 3 minutes in order to build pressure. I was told that if I did not let the pressure build, the transmission would act like it was slipping. I have always let it idle for at least 30 seconds and have never had the symptoms described above.

Mine seems to have one very hard shift from 2nd to 3rd or 3rd to 4th every time on fresh startup lately, but that's after at LEAST 5 minutes of warmup. I haven't really paid attention to what shift it is for sure because it suprises the hell out of me so far... As in: :wtf1: was that?!!! Only happens once. I'll pay more attention now. I don't ever recall that happening on my '03 8.1/Allison in the 53k miles I had it...

I do believe what your referring to is the ECM cutting back fuel while warming up and the TCM is expecting more power than being delivered therefore it's a awkward shift(s) till warm up.
Pretty much they all do it

Thanks for the info guys

I do believe what your referring to is the ECM cutting back fuel while warming up and the TCM is expecting more power than being delivered therefore it's a awkward shift(s) till warm up.
Pretty much they all do it
Oh... That would explain it.:ro)

Yep, mine does it, especially if I go around a sharp curve immediately after startup.

Your owners manual describes the warm up procedure for the Allison and why it shifts like that. The harder shifts are much more noticeable on warm up if your running a programmer of any sort. Your trans is used to shifting with the added power of the programmer and when in warm up mode the trans is not getting all the power it is used too, hence the harder shift. It is normal! A similar situation can arise if you unprogram the truck from a high tune. The trans will have to adapt to the lack of power and you will experience very hard shifts until it learns the new decreased engine power. It is always a good idea to drive with a light foot while the truck is getting up to operating temp. If the tranny temp needle is coming off the 100degree mark and the engine temp is over 170, put the hammer down!!

So, are all you guys going to pull your programs out?):h It will get rid of the problem.:rolleyes: I'm not.:cool:

mike