my truck is an 01 duramax with an allison... it shift good and at the correct time and everything but when you take off and it shift it kind of like pauses shifts then takes off again and it is not near as noticable when towing a heavy load... i'm not sure if this is normal or what but my other 01 duramax with the allison did not do this... should i service the transmission or what???

Nobody???

sounds lik its defueling to me

Does it do it all the time or every so often?

I just noticed my 03 started to do that interested to hear whats up with it

it does it just about everytime except when i'm pulling a load... it's like it takes off really strong let's off to shift then takes off again... it's weird

sounds lik its defueling to me
what exactly is defueling??

It's your computer reducing engine power during an upshift to reduce transmission slippage. May become more noticeable as mileage increases due to the transmission getting more wear on it & needing longer to complete a shift, meaning de-fuel time is longer as well.

Ok heres something iwerd...we have had some really bad weather here in Ohio the last 3 days....Tuesday we had 5 in. of snow....Then Tuesday night Wednesday turned to rain Sleet and ICE then back to snow another 4 in. Well Wednesday when going to work the truck went well....Parked it at work for my day at the office.....Went to leave....Remote started it....ran the 10 Min. on the remote start....went out right after it shut off started it with the keys.....Scraped all the windows and got in...Prob. 5 min. to do that.....went to back out....every thing was fine....the cell phone rang and it was the Wife.....Went to shift into drive.....AND IT WOULDNT GO ....... so I went back to park wile sitting in the middle of the parking lot....Went to drive again ....NOPE......went back to park....did this a few times....Finally with a little force it finally went into Drive......Made it home ( THANK GOD )...parked it in the garage....Not heated....went out this morning....Went into Drive just fine....talked to a few people and to what I thought ....the Trans. cable must have been frozen not letting it get to drive....Well after all that...I just wanted to know When daily driving....at 55...the trans. dont seem to shift into 6th gear alot....Some times it does and alot of times it dont....Is this normal?

It's your computer reducing engine power during an upshift to reduce transmission slippage. May become more noticeable as mileage increases due to the transmission getting more wear on it & needing longer to complete a shift, meaning de-fuel time is longer as well.
should i change the fluid or just the spin off filter

Depends on your mileage - there are threads here debating the internal filter change to a rather stupid extent, but IMO change both filters w/ the fluid. bill88 - linkage frozen more than likely, wouldn't sweat it. The Allison has different shift strategies based on temp to compensate for thicker cold fluid & to help warm up, etc., sounds normal as well.

Have you changed your fuel filter?