Allison 6sp: LMM Allison Hard Shifts Often

[t2timmy]

Hey Guys... I have a 2008 LMM with only 76,000 miles... Pretty often it has like a banging shift between gears 2-3 I believe. Has happened since I owned it. It almost feels like it clutches and then hits hard with a bang thud (like if you hit and drop the clutch on a manual trans). It happens more in Tow/Haul mode. This is my first dmax and I've owned it since 32,000 miles. I change the fluid and filter religiously (just did 2 weeks ago). I use the genuine Aliison filter and AC Delco Dex VI. Maybe it's just me.. but I've never owned a trans that shift so hard. It doesn't do it all the time. More when I'm actually good and ON the throttle. Is this normal??

 

[t2timmy]

Bueller ... Bueller ... Anyone?


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[kheims]

Could be a tuning issue. Causing a torque limit in the trans during that shift or something along those lines

 

[t2timmy]

Could be a tuning issue. Causing a torque limit in the trans during that shift or something along those lines

Hmmm....


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[Mike L.]

Could be main harness connecter is leaking fluid at the back of the trans.

 

[RHallenbeck]

Check to see that commanded and actual fuel pressure are staying close together.. IF it draining the rail it will shift late and harsh..

 

[t2timmy]

Thanks guys. Il check for any leaks. And il look into the fuel pressure though im Not sure how. Will have to look into it.


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