this is my first diesel and allison so everything I see and hear is new.


Are the allison tranny's normally a bit sluggish? I mean, I know they can handle a butt load of torque, but it seems sluggish at times. No issues or anything, but I am just comparing to a regular 4l80 tranny I had in my 6.0


thanks


B.

Yea - took me awhile to get used to mine feeling like I was driving a tractor while in 1st. gear and reverse.

the weirdest thing I've noticed is how long it takes to downshift and the lack of power for a instant if you stomp on it going around 30-40mph. Must be a feature to save the trans from getting butt loads of torque while it's trying to shift.

the weirdest thing I've noticed is how long it takes to downshift and the lack of power for a instant if you stomp on it going around 30-40mph. Must be a feature to save the trans from getting butt loads of torque while it's trying to shift.


is that the tranny doing that or is it turbo lag?

Diesel engines don't produce instantanious power. They have to
wind up, a bit. First gear is very low for get a load going from
a dead stop, kinda thing.

What you state sounds typical to me for a diesel. No problems.



Now if you don't like the lack of get up and go...... go to the
Performance thread. Do so at your transmissions own risk, though.

The only stupid question is the question you don't ask so........


I have a '98 Sierra 2500 6.5TD, 2WD, 8 foot box and extended cab automatic transmission VIN #F


What transmission (name and #) do I have?


I have 177,000 kms (no towing) should I change the AT fluid and differential fluid?


Please advise.


Reddy Diesel Flamborough Ontario Canada

4L80E

Had a long conversation with an independent mechanic (not affiliated with any dealership). His recommendation is to change out the transmission fluid and change the filter every 25,000 miles whether you tow or not. Claims if this is done and you do not abuse the transmission that it ought to give you 200,000 plus miles of trouble free service. Dealer will recommend changing every 50,000 miles but you'll be out of warranty and, if the guy I talked with is correct, the 50,000 mile change is in the dealers best interest, not yours.

the weirdest thing I've noticed is how long it takes to downshift and the lack of power for a instant if you stomp on it going around 30-40mph.* Must be a feature to save the trans from getting butt loads of torque while it's trying to shift.


is that the tranny doing that or is it turbo lag?

It's probably a bit of both. The only reason I say that is because my buddy has a '04 z71 chev and when you stomp on it in his truck the computer gives the tranny a second to shift before it opens the throttle all the way.