Questions on the allison

[William Lee Gingerich]

I just purchased a 05 duramax and I've put about 3400 miles on it now. I really like the truck it runs a little differently then our 02 truck.My question is when I'm towing in towhaul and I come to a stop the allison really whines on the downshifts especially when I'm on the brakes fairly hard. Our 02 does'nt whine near as loud. It seems louder the harder I push on the brakes as I'm slowing down. It seems directly related to how hard I push on the brake pedal.Did they increase the size of the pump on the allison in 05? Is this something I need to be concerned about? I have towed this same load many miles with our 02 duramax and it doesn't whine near as loud. Any help or thots would be great!!

[William Lee Gingerich]

I just remembered a few other things. I have changed the allison spin on filter twice now. I am very picky on maintenance. I have tried to follow Kennedy's advice on break in fluid and filter changes.

[madmatt]

are you sure it's the tranny and not the p/s pump whinning? the p/s pump powers the hydro boost assembly and generally make nioses that seem to be directly related to turning the wheel or applying the brakes when failing.

[JD Diesel]

It's just your grade brake coming on. Just did 2200 mile trip with my tralier did the same thing. made a lot of noise when slowing down. first camp site pulled the owners man out and read about it. No worries mate. JD :D Love the way that thing works :cool:

[William Lee Gingerich]

Thanks JD. It just concerned me because it was a lot louder then our 02 allison.

[William Lee Gingerich]

Thanks for your reply madmatt I missed it the first time.Maybe it is the power steering pump. Is there any thing I need to watch out for??? Thanks in advance!!

[VANBC2500HDDA]

My truck just did the exact same thing this weekend...

The powersteering fluid overflowed going up a big hill... and ever since it seems on braking when hot I get a whining noise...

I think its a powersteering, hydra boost issue as well but the GM tech that looked at it said everything was fine...

Do they make this noise under normal conditions? Or do I have a failure somewhere?

[madmatt]

No there shouldn't be any whining under normal op except for a little turbo whine. just pay attention to steering effort while braking.