Duramax romps when Allison shifts

[mtomac]

My truck is stock except for my "homemade" intake & plumbing pre-turbo. Under light throttle the Duramax romps a little when the Allison goes into 2nd and 3rd gear. The romp is similar to what I believe the level settings confirmation on the juice box sounds like. The truck has done this since day one and it really doesn't bother me I was just wondering if anyone else's dmax/allison does this.

[PEANUTGRWR]

I KNOW WHAT YOURE TALKING ABOUT. IN FACT ONE OF OUT TRUCKS DOES THIS TOO BUT ITS A 2001 AND HASNT BEEN REFLASHED. I WONDER IF YOU GET IT REFLASHED IF IT WOULD HELP, BETTER YET IS THERE A REFLASH FOR THE 2002???? YOU MIGHT LOOK INTO THAT TO START WITH. HEY I LIKE THE AIR BOX MOD. WHAT KIND OR WHAT IS IT OFF OF AND ARE THE FILTER ELEMENTS OF GOOD QUALITY???

[YZF1R]

Mine also does this. A little less than when it was new. It seems to mostly do it when cold or as the temp. is coming up.

[Vette Racer]

Mine did that too from new until the first hard tow. I hadn't thought about it until I saw your post and realised that it isn't doing it anymore. I guess about 500 miles with 15k on behind kind of settles them down and takes the "rump, rump" out. Mine has almost 6k on it now.

[Jomar]

WHAT DO YOU GUYS MEAN WHEN YOU REFER TO " ROMP or RUMP"????????????

[DarylB]

My truck does this as well at light throttle while first warming up in the morning. I always thought of it as a "surge" of sorts, probably something to do with the Allison's fluid warming up. You can really hear those planetaries early in the morning smile.gif

[dmaxstu]

jomar
That romp has also been referred to as the engine flairs in previous posts. In my truck it was happening a lot but it has now subsided as I'm getting more miles on it.However that said it still does it when using T/H and downshifts it sounds like there is some little leprechaun down there double clutching the damn thing. I would prefer that it just shifted quietly from one gear to another. Stu

[dschroeder]

My truck did this as well and I have a 2002. The dealer dowmloaded all the updates he could find and one of them was specifically for this I believe. It has not done it since I got it back.

[wq9e]

My early 2001 (Nov 2000 build date) did this, particuarly the 2 to 3 upshift when cold. I have been a holdout on the updates because it ran so well otherwise and mileage average was between 18.5 and 20.9 with a recent fast trip to N. Dakota resulting in 21.4 overall. However, the late shift to 1'st gear when stopping has been getting annoying so 2 weeks ago I had both the ECM and TCM updates done and the flare, late shift to 1'st and mild lope during warmup are gone. The shifts feel much more precise now. The first 2 fills since flash have resulted in 19.2 and 20.1 averages over a combination of interstate and city driving. I am happy with the updates! The "flash" effects many things apparently, even the speed sensitive volume is different. Truck is a 2001 D/A 4X4 EC SB.

[bigbobed]

Mine does it under light acceleration. My town has a 30mph speed limit. As you know, if you do anything other than very light acceleration you will be over 30 before you know it. Traffic fine revenue is a line item in the city budget.

[Searay90]

Yep, mine does it too... sounds like some "bliped" the throttle just a little bit and then let off quickly.

[horsehauler1717]

Flashing did not cure mine........my wife said it's all that power trying to get out

2001 D/A 25,000 mile's

[Jomar]

I guess I somehow missed the previous posting about this,but now that I know what you mean, my truck does it too. I asked the Chevy Tech. at the dealer about this several months ago and he said it was normal. It`s not real bothersome to me , but I`ll go back and have a conversation with them again. Thanks alot.


Jomar

[Jim Dandy]

Mine does it too. My build date was end of March. Mine does it especially loudly when shifting down from OD when towing. The RPM's naturally jump when downshifting but about 2 seconds after the shift they settle in about 400 RPMS lower. I'm going in for any available software updates in the a.m.

[Colorado Kid]

About 2 seconds after the downshift when towing, wouldn't that be about the time the torque converter clutch locked up in 4th? Not that I've ever experienced such a thing.

[Dinkie Diesel]

Mine does it too. It has also done the romp during parking lot manuevers twice and it has been updated for that IIRC. There has to be something causing it. How do you know if you have the latest updates. I think mine was done last winter.