i got a buddy that has a cab and chassis 3500 6.7liter spd auto 4wd 410 gears he hauls 17000 pounds all the time and says it pulls like a slug .said it will only pull grades 45 or 50 does that sound right thats alot of weight.he says the aison wont downshift on grades says it justs pulls down?? i drove it unloaded it seemed fine however i dont like not being able to lock out gears and shift like i do on my 68rfe. i thinks thats makes a bigg diff.kinda dumb the way they got it set up to me.does he need maybe a reflash or something for the tranny?

 

sounds like there is something wrong with his truck, but Ive never driven one but i doubt thats how its supposed to be. But it also depends on the speed that he's driving, especially with 4.10s. I know if im driving fast enough, even with 3.73s im sometimes moving to fast for it to downshift b/c it would turn it past redline...

 

never had that happen with mine you must be running 120mph then cause mine will downshift at 85 or 90

 

Yes,that speed is about right for grades.I think he is expecting too much for a 1 ton. On the Aisin Tow Haul elimininates 6,OD OFF eliminates 5th and 6th.
What does he use to pull in?

 

yeah thats what i thought this is his first inline.i told him if hes getting those speeds thats really good with that much weight.hes comeing from a v8.hes not use to how the inline revs he will get use to it

 

i dont think i can get mine to downshift on WOT above 75mph maybe 80mph so i dunno. Im sure if i used the paddle shifter it probably would but there are lots of times that i have noticed that it would not downshift. I guess ill wait til after i have the newest flash' and see what happens. Maybe im just losing me mind...

 

I think your buddy needs to have his checked out. I have the same type truck 2WD that I haul a 40' Trails West horse trailer with and it is around 17-k plus loaded with 4 horse and haul a 28' gooseneck hay trailer with 15-1200lbs round bales of hay. Pulls like a dream! LOVE IT!

I also drive it right when it is loaded, but have plenty of power on grades as well as flat land.

out does the 2005 with the 5.9L that I had before. Can not compair them at all.