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View Full Version : 2001 HD Allison performance valve body replacement advice



Chop Top
04-24-2012, 02:37 PM
Awhile back I had some GM service done on my 2001 Chevy Duramax Allison automatic transmission. The shift points were slamming from 1-2 and 2-3 due to blowby in the throttle valves. The tech told me that aeventually I would need to consider an entire valve body swap if it gets bad enough. It's wearing out bad @ 220K on the ode.

Well, a year later and it's now bad enough to address. I have lost accurate shifting capability form 2-3 and 3-4 for passing and pulling. I mean the truck does fine, it's just slow and with no pressures between shifting due to massive blowby. If I make it another year pulling the camper I'll be happy so I'm hedging funds for some major service again. I want to go hunting in Colorado, and the mountains will be brutal if I try to travel long distances with it like this.

I need help and/or advice on the following:

1) What good brands would I need to look at for a total TB swap.

2) How hard of a job to do myself -vs- having my mechanic do it ? I know my way around an automatic transmission if it's a simple plug and play. If there is tuning and reflashing involved then I'm lost.

Here is one I found while googling around. Or is this even what I need ?

http://www.thoroughbreddiesel.com/suncoast/valve-body.htm


My thought process is that for what GM wants for the factory replacement I can enhance the truck's performance with an aftermarket part for the same money (about a grand).

CarolinaHD
04-24-2012, 03:53 PM
with that many miles and the shifts slipping and burning the clutches as bad as it is i would be looking into a full rebuild/built transmission. such as a suncoast stage III or something similar and would only be a few hundred more(than a grand)

Chop Top
04-24-2012, 06:53 PM
I was told the replacement trannies are like 6K. Am I wrong ? And if so then what can I expect to spend on a good rebuilt auto for my model ? I just put 1500 in a new transfer case last year.

I want this truck to last. The engine is unstoppable but the tranny is getting tired.

Jmac72
05-01-2012, 08:54 AM
I would just get yours rebuilt.Around here a stock rebuild is about $3k a suncoast V is about $5k.If you buy another the core charge is $800 or so.