I currently have an 06 newmar mountain aire with the 8.1 engine and Allison 5 speed. We love our MH but would like to have the 6 speed tranny. Would I see many benifits and is this feasible and cost effective if I could locate a tranny that is

The 6 speed gives you the grade brake option and a second overdrive. The second overdrive is not much help in the mountains. ALso when they went to the 6 speed, they changed the rear axle ratio. The five speed transmission control module can be reprogrammed to give you the grade brake feature. The 5 speed has a sensor for the transmission fluid temperature that can be read with a ScanGauge. The 6 speed does not have the capability to read the transmission fluid temperature with the ScanGauge. Pros and cons for each but I would stick with your 5 speed rather than go through the expense to change everything.

JCMack wrote:I currently have an 06 newmar mountain aire with the 8.1 engine and Allison 5 speed. We love our MH but would like to have the 6 speed tranny. Would I see many benifits and is this feasible and cost effective if I could locate a tranny that isTo do the proper change over will in crude a different transmission, ECU, wire harness, and a different rear differential. quite expensive for what you gain.

If you could get one from a salvaged coach for next to nothing, it might be worth your time, but there will be a lot of electronic changes to make and possibly a differential change.If you have to pay retail for everything and have someone install it, you'll never recoup the money in either fuel savings or even performance increases.

In some 5-speed applications, it was only a programming change to make it into a six speed. If it were me, I'd look into that and see if it might apply to what I had.5 to 6 speed reprogramming

I've had Chevy trucks with both the 5 speed and the 6 speed Alison. I had the 5 speed behind an 8.1 and a Duramax and the 6 speed with a Duramax. I actually prefer the 5 speed. When you go to "step on it" and pass someone the 6 speed has to down shift twice to get to direct drive, the 5 speed only once.I never really saw any advantage to the extra gear.The 5 speed Alison in the trucks had the grade braking feature since the beginning in 2001. I would think it would have it in a MH too.

allison 5 to 6 speed transmisson change out | Good Sam Community

rgatijnet1
Explorer III
Dec 21, 2015
The gear ratios for the first five gears is the same for the 5 speed and the 6 speed Allison transmissions. Adding the 6th gear added an additional overdrive that went from 1:1 ratio in 4th to a .71:1 ratio in 5th and a .61 ratio in 6th.
For that reason Monaco/Workhorse changed the rear axle ratio to allow the engine to be able to pull the second overdrive. I'm not sure what the other manufacturers did but it seems to me that the ONLY place that you may be able to use the 6 speed conversion would be on flat and level roads, with a lightly loaded coach, unless you change the rear axle ratio as well. Naturally you will need to reprogram the TCM and the ECM so that all of the electronics recognize the change in the transmission.
I think the gain is going to be very slight and only useful in a minimum of conditions.
Hideout17
Explorer
Dec 21, 2015
I worked alongside Chevy techs in a dealership. One tech told me the 6spd Allison is same trans as the 5spd with an EC program. Not totally sure what years that was for.
Hank_MI
Explorer
Dec 21, 2015
Alphamonk wrote:
Just a thought but Gear Vendor specializes in just this problem.

I believe the Gear Vendor unit is an aux trans/overdrive that attaches between current trans and drive shaft. Lot more involved than just reprogramming a trans.
Alphamonk
Explorer
Dec 21, 2015
Just a thought but Gear Vendor specializes in just this problem.
rgatijnet1
Explorer III
Dec 21, 2015
Contact this place that specializes in reprogramming Allison transmissions and ask an expert. Ultra RV products
nevadanick
Explorer
Dec 21, 2015
As Tderonne said, you can likely have it programmed as its likely a 6spd with 6th programmed out. If you search Kodiak forums you can find detailed info on getting it done.
KD4UPL
Explorer
Dec 20, 2015
I've had Chevy trucks with both the 5 speed and the 6 speed Alison. I had the 5 speed behind an 8.1 and a Duramax and the 6 speed with a Duramax. I actually prefer the 5 speed. When you go to "step on it" and pass someone the 6 speed has to down shift twice to get to direct drive, the 5 speed only once.
I never really saw any advantage to the extra gear.
The 5 speed Alison in the trucks had the grade braking feature since the beginning in 2001. I would think it would have it in a MH too.
tderonne
Explorer
Dec 20, 2015
In some 5-speed applications, it was only a programming change to make it into a six speed. If it were me, I'd look into that and see if it might apply to what I had.

5 to 6 speed reprogramming
DSDP_Don
Explorer
Dec 20, 2015
If you could get one from a salvaged coach for next to nothing, it might be worth your time, but there will be a lot of electronic changes to make and possibly a differential change.

If you have to pay retail for everything and have someone install it, you'll never recoup the money in either fuel savings or even performance increases.
Tom_Barb
Explorer
Dec 20, 2015
JCMack wrote:
I currently have an 06 newmar mountain aire with the 8.1 engine and Allison 5 speed. We love our MH but would like to have the 6 speed tranny. Would I see many benifits and is this feasible and cost effective if I could locate a tranny that is

To do the proper change over will in crude a different transmission, ECU, wire harness, and a different rear differential. quite expensive for what you gain.