Allison 6sp: SC 1056, 1058 or Precision ML

nsolimini

New member
Sep 18, 2011
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Lakeland, FL
So I have tried reading A LOT and kind of have an answer to some of my questions, but I am still not certain. Please forgive any lack of knowledge on torque converters as they are new to me looking into them.

I am building my trans soon and I am wondering what TC will be good for my needs. For the next year or two I will have a stock turbo and stock injectors. This truck is my daily driver, but I will also use it to play around on the street, and once in a blue moon take it to the track.

I think for me the best TC will either be a 1058 or the precision ML TC. Are there any other opinions out there? What would be the pros/cons for my setup?

Thank you :beer
 

othrgrl

Diesel Addiction Owner
Mar 10, 2008
2,151
4
38
Wilmington NC
www.mydieseladdiction.com
I think that either of those would be a good choice. The 1058 work well with a stock turbo up to a small S400 like a 468. In my opinion it is a little too tight to get on top of bigger s400s. The ML works awesome for any stock or variable vane turbo and for S300s, but I feel it is a little too tight for S400s. Dialed in a truck with a cast 468/87 yesterday that had an ML and he could have used a higher stall converter. Terry at Precision custom made a converter for my personal truck back in 2009 that is perfect for a big charger that gets driven on the street. It will stall right up to 3,000 RPM but still couples and feels like a tighter converter as soon as you are moving. We've sold a lot of them since and call them the DA series.
 

nsolimini

New member
Sep 18, 2011
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Lakeland, FL
Thank you Othrgrl, so it does seem like I am on the right track!

SPhinney, I have read everyone say that, but what do they mean? Currently when my stock converter locks, it just feels like the truck shifted into 6th.
 

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
1
38
Berthoud, CO
I have about 300 miles on my 1055 with a modified stock valve and the lockup is nothing different from my 1056. Just firm enough. However it does just have the transgo kit in it.
 

DaJokr

Slum Lord Extraordinaire
Mar 7, 2013
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Prince George, BC, Canada
Mine does. This isnt your average 500hp built trans though. It is running very high line pressure with zero knockdown. Let's just say you know when it locks.:thumb:

Can vouch for that. First few hundred miles the tires chirped every time it locked up. Broke in now it's much better, but still a solid/firm lock. You KNOW it's locked. Love my 1058.
 

nsolimini

New member
Sep 18, 2011
72
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Lakeland, FL
I have a couple buddies running the 1058 on the stock charger and they have no complaints. However the 1058 was the only TC they have run, so they didn't have any input into the 1056 or the precision ML.
 

N2BRK

Well-known member
Dec 31, 2009
2,055
373
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I'm still debating this on my build. I just got off the phone with George and my appt is next Saturday :woott:

I'll be running Mark's new 68stg2R, and I need to decide between the 777, 1056, and the 1058. :confused::confused::confused: I DD the truck and do everything in the world from grocery getter, commuter, family trips, light and super heavy towing. Too many choices, lol.


Wally