Question on Upgrading Allison 5 spd to 6 spd

[Greyghost]

I am contemplating upgrading my 2003 Allison 5 spd transmission to a 6 spd. I have talked to an Allison Service Center and apparently it's simply a reprogramming of the transmission. I'll need an OK from Workhorse and possibly Newmar before they can do the reprogramming. My question is; has anyone had this done and if so, was it worth the $250.00?

[oemtech]

Quote:

Originally Posted by Greyghost I am contemplating upgrading my 2003 Allison 5 spd transmission to a 6 spd. I have talked to an Allison Service Center and apparently it's simply a reprogramming of the transmission. I'll need an OK from Workhorse and possibly Newmar before they can do the reprogramming. My question is; has anyone had this done and if so, was it worth the $250.00?

1) I have looked into this before and it involves more than reprogramming.

2) Unless you have some for of extended warranty or something special from Workhorse and/or Newmar you don't need any approval for either of them.

[DriVer]

The upgrade if possible will require a new TCM which we all have seen as being different on the 6 Speeds.

The ECM has to be able to figure out that the transmission is in 6th gear which it would know nothing about. New calibration file (if possible)

Your instrument panel will never show that you are in 6th gear.

The 5 Sp OD lockout switch will not be able to address 6 speeds.

Honestly, I see this running more than $250.00. If this task could be accomplished for $250.00, I'd say more people would have pursued this by now since the 6 speed tranny has been in service for 4 years.

Good luck in pursuing this project.

[Greyghost]

Thanks for the responses.

The permission/letter from Workhorse is more about Workhorse stating that the installed drive train will be able to handle the 6spd.

I suspect that the ECM is part of the reprogramming, but I wasn't aware of that so I'll tuck that away for when I get back to Pheonix. As for the IP, I've already considered that one and will wait until I get all of the loose ends tied up before I commit.

[DriVer]

Quote:

Originally Posted by Greyghost I suspect that the ECM is part of the reprogramming, but I wasn't aware of that so I'll tuck that away for when I get back to Phoenix. As for the IP, I've already considered that one and will wait until I get all of the loose ends tied up before I commit.

Greyghost, You have to ask yourself, Does it matter OR will I ever recover the cost of the upgrade for the benefit of .010 less of a gear in 2nd overdrive? (6th gear = .061:1)

For the lower gears from 1 to 5 there is no difference. It's not going to pull better with a 6 Speed.

[sknight]

The Allison 5 and 6 speeds are slightly physically different. It's a direct bolt in and the internal gearing is the same but the valve body and the corresponding passages in the case are different, at least that's what they told me in class. We proved on the bench that all you have to do is lockup one clutch that's used in another gear.

It'll be interesting to see if a new control arrangement is all that's needed.

[Greyghost]

Quote:

For the lower gears from 1 to 5 there is no difference. It's not going to pull better with a 6 Speed.

That's the most significant response yet. I never worry about cost recovery. However I do like to know if there is a true benefit to the upgrade and that's the reason for the post. I was hoping that it would pull the hills better. If not then I'll need to talk to Brazels and see what they can do.

Thanks again.

[Batman_777]

I don't understand. If the 6th gear is for inproved hill climbing, wouldn't you want 4th or 5th? 6th gear would not improve hill climbing but bog down.

The only reason I can see for the 6th gear is improved cruizing on flat. And isn't that like overdrive or torque converter lockup? Or is it a true additional 6th gear?

[JMonroe]

Quote:

Originally Posted by Batman_777 I don't understand. If the 6th gear is for inproved hill climbing, wouldn't you want 4th or 5th? 6th gear would not improve hill climbing but bog down. The only reason I can see for the 6th gear is improved cruizing on flat. And isn't that like overdrive or torque converter lockup? Or is it a true additional 6th gear?

I suppose it depends on where that 6th gear is. We're all assuming it would be on the 'top' end, a greater overdrive. I know I was. But, what if they're talking a new gear 'below' the current 1st, or somewhere in between the existing lower gears. That could help with pulling a grade.

Still, it sounds too easy. Simply reprogram a 5 speed to make it a 6 speed?

[DriVer]

Quote:

Originally Posted by Batman_777 The only reason I can see for the 6th gear is improved cruising on flat. And isn't that like overdrive or torque converter lockup? Or is it a true additional 6th gear?

Batman_777, The 6th gear on the Allison 2500 Series transmission is a true 6th gear. It's function is to be a 2nd over drive. This gear is no where near a power gear since it wouldn't be able to negotiate a speed bump from a standing start in 6th (if that were possible).

The torque converter does lock up in any speed other than 1st and it indeed does improve economy while cruising in 6th gear.

[DriVer]

Quote:

Originally Posted by JMonroe Still, it sounds too easy. Simply reprogram a 5 speed to make it a 6 speed?

Jmonroe, There isn't anything very drastic between an LCT1000 and the 1000MH. Electronics does indeed have a very significant impact on how each of these transmissions responds. I understand that the new generation of electronics (TCM) makes it possible for the 1000MH 6-Speed to exist.