View Full Version : Allison 6 speed conversion installed
I won't be driving it until tomorrow, but the 6 speed conversion has been installled in my 2005 for testing...
More Power
11-11-2006, 00:18
Cool! What's involved in the conversion?
Jim
Valve body and TCM swap. Pretty simple installation. The only catch is the need for a proper core valve body with the G (modulated main) solenoid which came in 2004+ trucks.
P.S. Suncoast developed it.
DmaxMaverick
11-11-2006, 11:16
Wow! This got my attention! Now I have questions. If you'd rather wait for answers, that's OK. I'm patient.....
Does it allow gear lockouts and/or push button shifting, like the late Allisons?
Is the TCM a reprogram, or replacement?
Are the shift points the same? Can they be adjusted with the TCM swap?
Now, for the big questions....
What's a balpark figure for a pre-2004 upgrade? Is a pre-2004 even a candidate? I'm about to do a Suncoast upgrade, and would like to consider it at the same time. Is Suncoast planning to offer this in their upgrade packages?
I have other questions, but I'll wait for the official report.
Sorry John, but you started it!
Jake99Z71
11-11-2006, 15:28
Wow! This got my attention! Now I have questions. If you'd rather wait for answers, that's OK. I'm patient.....
Does it allow gear lockouts and/or push button shifting, like the late Allisons? No
Is the TCM a reprogram, or replacement? a replacement
Are the shift points the same? Can they be adjusted with the TCM swap?
The shift points are optimized for 6th gear. No, they are fixed.
Now, for the big questions....
What's a balpark figure for a pre-2004 upgrade? Go to Sun Coast's Website. Is a pre-2004 even a candidate? Yes, 01-05 can be upgraded for the same cost.
I'm about to do a Suncoast upgrade, and would like to consider it at the same time. Is Suncoast planning to offer this in their upgrade packages? Yes, you can buy it at the same time.
I have other questions, but I'll wait for the official report.
Sorry John, but you started it!
This should help answer some of your questions.
It's hard for me to drive 62 mph now w/o the cruise. I guess that's becuase I often drive by ear/feel like I do on my Harley and check speedo periodically. It's really quite nice, but I don't know if I'd expect any huge mpg gains. Held 6th in all of our rolling hills here (empty with econo tune) which is a good thing. These little hills sneak up on a guy.
Today's plan is to haul (and learn to operate myself) the 20k#-ish dozer/tag trailer combo pictured here:
http://www.kennedydiesel.com/photogal/images/dmaxwbulldozer.gif
a5150nut
11-12-2006, 10:23
Kennedy, you have helped us all with your information. If you would like a few pointers on running your new toy, I have 35 year behind me playing in the dirt.
06bowtie_guy
11-12-2006, 13:40
Little offtopic but got any specs on the trailer you are pulling?
Also what's the weight of that dozer? Looks like the truck handles it fine.
DmaxMaverick
11-12-2006, 14:19
Little offtopic but got any specs on the trailer you are pulling?
Also what's the weight of that dozer? Looks like the truck handles it fine.
Looks can be deceiving....And John cheats.
That dozer should weigh in at about 7 tons. That's a lot of weight, even on a class V hitch. Can't do that legal in most states/provinces.
Looks can be deceiving....And John cheats.
That dozer should weigh in at about 7 tons. That's a lot of weight, even on a class V hitch. Can't do that legal in most states/provinces.
Yes we cheated in a big way. That pic was my 2002 2 years ago. I didn't have time/forgot to get a pic with the 2005. Both trucks carried the load well, as both are long wheelbase and set up for heavy towing/load carrying.
We kept the machine back over the axles, but in reality, it was still biased ahead of center a good bit. There was also a Wacker packer on the nose of the trailer. We scaled the combo at 28,200# then added 250# of corn, 220# for me and 135# for my daughter. I used a small pintle mount in my Draw Tite receiver. The 2002 carried this on the OE receiver.
So on to the 6 speed. I started out with my Economy tune which got us up to speed and handled the load qiuite easily, but the pedal position
necessary to maintain speed did not allow us to get into 6th gear at 60 mph except on very flat or downhill. Standard 5th gear was no problem. I switched to the big tune and it ran in 6th most of the time. When I got to a hill that it couldn't handle, it dropped out of 6th smoothly and remained in 5th for the rest of the hill dropping back to 6th as soon as the hill was crested. The truck really wanted to run 65-70+ but I didn't. I think if it were run that fast it would have held 6th gear much better on the few hills that it couldn't.
Kennedy, you have helped us all with your information. If you would like a few pointers on running your new toy, I have 35 year behind me playing in the dirt.
Thanks for thr offer. Next time you get to WI, let me know:D
I didn't do too bad, but rocking over center forward got the better of me a couple of times. I did good loading and unloading when I expected the rock.
a5150nut
11-14-2006, 21:41
So the conversion adds one more gear below direct? 6th being overdrive/
No it's a double Overdrive like the 2006 trucks have.
If you don't mind me asking, what are the mirrors that are pictured on your truck? I am looking for mirrors that extend out for trailers, but do not have the huge blind spots that the factory extend mirrors have. Where could I find these mirrors?
a5150nut
11-15-2006, 22:38
So do you do that fancy corragated dozing? The kind you can't back up over very fast. Or then there is notching for railroad ties. Always quite impresive!
Idle_Chatter
11-16-2006, 21:28
If you don't mind me asking, what are the mirrors that are pictured on your truck? I am looking for mirrors that extend out for trailers, but do not have the huge blind spots that the factory extend mirrors have. Where could I find these mirrors?
Those are Schefnacker (also called TTT) mirrors and John Kennedy sells them.
WILLYD-MAX
11-17-2006, 12:10
And...they are some of the best towing mirrors out there. They extend a total of 4" further then most any mirror:D
What kind of change did the added gear make on fuel economy?
And how would this modification work with the edge products?
Mark Rinker
12-20-2007, 07:52
John - any updates on the Suncoast 6spd conversion kit? How has longterm use faired?
Could this kit be used in my 2004 Kodiak? Looking to lower cruise RPMs, especially when running empty and 'fast' (only 68-70mph, its all relative).
Anyone else running this kit?
Jake99Z71
12-20-2007, 17:36
I've been running it as long as John has. It's good for .5 mpg better economy. I don't see why you couldn't run it in your Kodiak. Call Sun Coast and talk to them about installing it. They might need to tune your TCM a little different. A built trans would be better in your truck running this too.
Is it worth is for just 0.5 mpg gain? The conversion is somewhat pricey.
On a side note, this forum is backwards than what I am used to. Seems the newer pages in a thread are the lower numbers. Took me like 5 minutes to make sense of THIS thread cause I started reading it backwards. :o
Jake99Z71
12-27-2007, 10:57
The other thing you need to think about is 325rpm lower engine speed. How does this effect wear on the engine?
DmaxMaverick
12-27-2007, 14:51
Is it worth is for just 0.5 mpg gain? The conversion is somewhat pricey.
On a side note, this forum is backwards than what I am used to. Seems the newer pages in a thread are the lower numbers. Took me like 5 minutes to make sense of THIS thread cause I started reading it backwards. :o
Go to your User CP options and change your page display. Also, while in reply post mode, it will show the newest post at the top, oldest at the bottom. If all else fails, the date and time is on each post.
Go to your User CP options and change your page display. Also, while in reply post mode, it will show the newest post at the top, oldest at the bottom. If all else fails, the date and time is on each post.
Got it thanks.
I have a valve body for a 6 speed allison and can install it on my 5 speed. Where can I send my tcm for reprogramming to enable the 6th speed?
Most places want to sell the valve body and tcm.
Jake99Z71
01-08-2008, 17:21
A 6spd valvebody will not work in 5spd trans. You need a modified 5spd valvebody.
pjt97k2500
01-04-2013, 13:03
I have a 2005 GMC 3500, DMAX with 5 speed Allison. Sounds like it is possible to swap the 5 speed for the 6 speed, correct? We have a 2010 2500 with the 6 speed and I like the rpm's it runs down the hiway at.
Freightliner3
01-04-2013, 19:24
I had my truck up graded to 6 spd in 2007 The kit came from Sun Coast Convertors in Florida.I had a local speed shop do the work. After 6 years
and a lot of driveing. I'm happy to say it works so well that I've decided
not buy a new truck any time soon.With all the emission issues and problems
the price of the 6spd up grade has saved the cost of a couple new trucks.I use to trade every 3 yrs.
Good Luck!
pjt97k2500
01-09-2013, 07:45
So, it looks like I just have to change the TCM and valve body, do not have to physically change the tranny, correct?
Yes
What I put in mine (no longer my truck) is the Suncoast 5-6 conversion kit. It's an exchange valve body and TCM. Of those that I have sold over the years I have yet to hear any complaints, but also nobody bragging on MPG gains either. It's just nice and quiet with the reduced RPM.
There is one thing to keep in mind. You have limited control or knowledge of what gear you are in. If you select TH it will not shift into 6th. OD lockout still goes down to 4th.
There are tap shift kits available, but I've seen mixed results at best.
pjt97k2500
01-14-2013, 17:43
Thanks for the response. I do not tow heavy loads and with an automatic, do not worry too much about what gear I am in. Having a bit of a trucking background, I like to reduce rpm's; adds life to the engines. Can a backyard farmer, trucker mechanic change the TCM and valve body or are there special "J" tools required?
Thanks
Yes
What I put in mine (no longer my truck) is the Suncoast 5-6 conversion kit. It's an exchange valve body and TCM. Of those that I have sold over the years I have yet to hear any complaints, but also nobody bragging on MPG gains either. It's just nice and quiet with the reduced RPM.
There is one thing to keep in mind. You have limited control or knowledge of what gear you are in. If you select TH it will not shift into 6th. OD lockout still goes down to 4th.
There are tap shift kits available, but I've seen mixed results at best.
I realize this thread is a bit old, but I recently purchased a used Suncoast 5-6 speed conversion kit.
I have noticed that the Suncoast valve body has an extra module with a solenoid fitted, but there is not harness plugged into that solenoid nor do I have a harness in my existing Allison that would plug into it, any idea, thanks for the info.
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