Roger10378
Goodrich, MI.
Full Member
Joined: 05/29/2008
View Profile
Good Sam RV Club
 Offline
|
The Hydromatic 6 speed is designed for max 500 Ft lbs of torque. The allison is a lot higher( 800 I think). So if your engine is not capable of over 500 ft. lbs you are OK with the Hydromatic. Thats why the allison is standard with the Duramax (600ft lbs).
2005 Cardinal 30TS
2007 Chevy 2500HD D/A
|
blt2ski
Kirkland, Wa
Moderator
Joined: 03/15/2001
View Profile
Offline
|
If the question "IS" related to the difference between the 6L90E and the Allison 6 speed. Besides the above torque capacities. the ratio's are also different. The allison has a 3.08 or 3.1 first gear, with my above written OD and DOD gears. The 6L90E has IIRC a 4.1 or 4.5-1 first gear, with no direct, but 5th is a slight OD, 6th a DOD of about .64. 4th IIRC is about 1.1-1. From the magazine test results, the 6.0 SB8 gasser is keeping up or bettering test results with the 4L80E and 8.1 V8 BB gas results. And very close to the same results as a D/A combo.
I tow upwards of a 12K equipment trailer, and a 4.10/6L90E 6.0 gas would have been my next truck had that combo been out in 05 when I got my current rig. With the low first gear, even a 3.73 gear rig is lower overall starting ability than a 4.10 much less 4.56 gear 4L80E rig, with its 2.48-1 first gear!
Marty
05 Chev CC D/A LS Dooley
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
00 Chev C2500, V5700, 4L80E, 4.10, base truck, no options!
92 Red-e-haul 12K equipment trailer
3 Single axle utility trailers
Check RV.Net Blogs at: blog.rv.net
|
Big Shoe
Exit 1-NJ Turnpike, PENNSVILLE, NJ
Senior Member
Joined: 07/08/2004
View Profile
Good Sam RV Club
Offline
|
Holy Cow ! Did I mention I'm not a mechanic....lol.
Thanks for the information. It gives me some additional things to consider. I am in the market for a crew cab with a diesel and right now I am researching.
Thanks !
Just Me & the Boss !
2002 Chevy Suburban 4WD
2005 Sunline TT T-264SR
BIG SHOE
|
jaycocamprs
Ringgold Georgia
Senior Member
Joined: 03/28/2004
View Profile
Offline
|
The ZF-6 was the "standard transmission". The Allison was optional. Now all most all Duramax truck were equiped with the Heavy Duty Power option which included the Duramax, Allison and the Eaton locking rear end. but till 07 it was a option.
2005 Silverado 3500 DRW
2007 JayFlight 28.5 RLS
|
miltvill
Ft. Lauderdale FL
Senior Member
Joined: 10/20/2008
View Profile
Offline
|
Here is a link for more info. Click on the link then click on the download.
Link
2008 Chevy 2500HD Duramax Diesel, Allison Transmission, 3.73 rear end, tow package, Prodigy Brake Controller, Equal-i-zer Hitch.
Trail Cruiser TC23QB
|
|
|
wildernesshd
Alex.,La.
Full Member
Joined: 12/21/2008
View Profile
Offline
|
cruise engine braking works on My 03 d-max allison 5 spd. and there are a few companys offering conversion valve bodies and computer programing to make the 5 speed into a 6 speed. what I understand is the internals are basically the same between the 5 and 6 speeds allisons. and a DOD would probably increase unloaded fuel mileage
2003 GMC 2500HD ccsb DURAMAX Allison 3.73 ratio 285/75/16
2000 Wilderness 34 5L 3 slides 36 ft
statements in this post should be considered opinions and not facts
|
azbound
Redding, Ca.
Full Member
Joined: 10/17/2009
View Profile
Offline
|
If you are referring to the Chevy/GMC trucks, I don't think there is an optional 6 speed Allison. In 2006 they changed from the 5 speed to the 6 speed and I don't think the 5 speed is longer available in the GMC trucks.
Gary and Janet (countryrose)
Redding, Ca.
2009 Bighorn
2008 Chevy 3500 D/A DRW
|
Paul Clancy
BC Canada
Senior Member
Joined: 09/16/2005
View Profile
|
http://mrtruck.net/allisonpress.htm
See this for what updates were done to the 6speed allison
From the 5 speed faq
Q. Automatic Grade Braking - When will I get a downshift?
A. There is no 'fixed' shift point for a 'grade braking downshift', however, the shift will never occur such that the engine speed following the shift exceeds GM Truck guidelines. Also, the shift will never occur without depressing the brake pedal.
No mention of cruise grade braking
http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11#89
|
Turtle n Peeps
California
Senior Member
Joined: 06/23/2008
View Profile
Offline
|
Quote:In a Suburban Duramax, the Allison is not standard a 480LE is with the Allison optional. A 480 is a Turbo 400 w/OD.
There is no Duramax in any Suburban. It never happened. And the 4L80E was never in back of a D-Max.
~ Too many freaks & not enough circuses ~
"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"
|
RCMAN46
NorthWest
Senior Member
Joined: 02/24/2008
View Profile
|
Boy sure a lot of postings that are not on topic. The OP asked about an optional 6 speed. The 09 GM Allisons are only 6 speed. No optional transmission offered in the Allison. As for the 5th gear being 1:1 that is not correct. 5th gear in both the earlier 5 speeds and the later 6 speed is a 0.71 ratio. Before people comment sure would be nice if they had their facts correct.
|
|
|
