5 to 6 speed conversion

[02CCSB]

anyone know how I would go about this? or am I forced to buy a locked TCM? I doubt a simple OS re-flash would do it.

Yes I have a valve body.

[THEFERMANATOR]

If you have a 01-05 DURAMAX truck with a 5 speed and want to make it a 6 speed, you are pretty well limited to the SUNCOAST kit. The 6 speed valve body will not just drop into a 5 speed and then have a 6 speed OS flashed in(tried this). You have to use the 5 speed style solonoids which means you have to run the kit. And if it is a 01-05 truck, there is no factory or ALLISON flash to enable 6th gear. If you have an 06-07 MD with a 5 speed, then yes it can be flashed to a 6 speed by ALLISON, or if you have a 8.1L you can swap in an 06 TCM, 6 speed valve body, modify the wiring harness, and have a 6 speed.

[02CCSB]

Hmmm...OK... I get what you are saying about the solenoids, makes sense.

It's an 02. Access to various VBs is not an issue, but, without that software for the G solenoid, I'm SOL...

[THEFERMANATOR]

The G solenoid has nothing to do with the 6 speed as the SUNCOAST 5-6 speed kit doesn't use it(but they do use a G solenoid type valve body). The problem is having the 6th gear pipe installed in the valve body which means you have to start with a 04-05 5 speed valve body to be able to install one. Then you have to have the software to command the extra shift of the C2 and C4 clutch pack for 6th gear. ALLISON has the TCM OS, but they won't pass it up and I doubt it is even on there servers for download if you had access to the ALLISON DOC. For an 01-05 to get 6th gear, your only option is the SUNCOATS kit if you want everything to work like stock(some have installed a GEN IV 6 speed TCM and made the other changes, but it still won't work as designed as the GEN IV TCM will be working in default mode without receiving the GM high speed can bus data protocol messages from the BOSCH ECM). I looked into this myself last year(even bought the 6 speed valve body and associated components) to only find out the software was a hurdle not easily overcome.

[LB72004]

what about the cost (suncoast kit) vs the benefits? is it worth it? do you get that much better MPGs????:confused:

[Wheelz]

Would it not be cheaper to sell your tranny and tcm and buy a 6spd with tcm? Or is there a lot of other stuff that would still need to be done?

[THEFERMANATOR]

The 6 speed TCM is a GEN IV ALLSION TCM, and there is no known OS for it to communicate with the older 01-05 J1939 can bus they used as the newer GEN IV OS uses GM LAN high speed canbus.(don't hold me to the exact descriptions of each com system as I get em mixed up easily). You can put one in and hook it up, but it won't talk to the ECM and leave you in limp mode so its sort of pointless. There is a reason that SUNCOAST sells this kit as it is the only way to put a 6 speed behind a LB7 or lLY and have a true 6 speed. And yes it is a locked TCM, so you can't make any shift point changes to it. If you have an 8.1L though, you CAN swap in a GEN IV TCM into it and 6 speed trans and wiring and have a 6 speed as the SUNCOAST kit doesn't work for gassers but the GEN IV 8.1L TCM does talk in low speed J1939 can like teh older 01-05 trucks used(all of the 8.1L's used low speed data).

[LB72004]

would one be able to run the 6 speed in a stand alone setup? just need to feed it throttle position right? is there anything you would loose hooking it up this way. i assume you would have to flash your ecm with a manual trans tune or at least turn off the codes.

[THEFERMANATOR]

would one be able to run the 6 speed in a stand alone setup? just need to feed it throttle position right? is there anything you would loose hooking it up this way. i assume you would have to flash your ecm with a manual trans tune or at least turn off the codes.

No tap shift, no gear display in the cluster, no tow/haul mode, no coms with the ECM meaning no defuel, and probably end up with a fried trans. It could be done, but would be a disaster hence why those who have tried it didn't do it for long.

[killerbee]

If you have the modified valve body, I can supply the 6-speed (01-05) TCM.

[i911fire]

If you have an 8.1L though, you CAN swap in a GEN IV TCM into it and 6 speed trans and wiring and have a 6 speed as the SUNCOAST kit doesn't work for gassers but the GEN IV 8.1L TCM does talk in low speed J1939 can like teh older 01-05 trucks used(all of the 8.1L's used low speed data).

I have a early 2004 8.1L/Allison (1000PK) the numbers on my TCM are PN 29537441 11/19/2003 S/N: BKDUTCM333230962 Brodcast Code 9833 230962 Service Number 15768288

I am sure that tells you anything, but I was wondering just what exactly I need to convert over to the 6 speed. I do a lot of driving and squeezing more MPG out of my truck would be very helpful.

Thanks
Ryan

[THEFERMANATOR]

Theres a few write ups on it, but the 06 8.1L TCM uses the old style data communications. So you can swap to an 06-07 trans, wiring harness, and TCM into your older 8.1L and make it work. In the end the milage savings will probably never equal out what it woul cost you to swap everything over. There has been a few that have done it in the past, but the cost was a factor.

[Whipped383]

Im in the 8.1 boat as well. I just saw killerbee listing tcms on ebay and was wondering if anyone had more info on this. Is there a reason the suncoast kit wont work on the gassers? And links or writeups on doing the 6 speed swap on a gasser?

[Cougar281]

The suncoast kits are designed for the duramax. The valve body would work, but the tcm would be all wrong. They MIGHT be able to make a TCM for a gasser, but personally, I wouldn't touch one of their 6 speed conversion tcms with a 10 foot pole.

If you have a 03+, are mechanically and a little electronically savvy and have some patience, you could probably get a 6 speed transmission, body harness and TCM for less than their TCM. IIRC, I paid less than 1k for my 6speed trans and was able to more than recoup that when I sold my freshly rebuilt 5 speed.

If you have a duramax, IMO, the ONLY way to do it is to completely convert to a lbz/ 6 speed as I did. If you have an 03+, its largely plug and play. 01-02 not so much. That way you get all the 6speed benefits (including tap shift and the enhanced winter warmup idle which works much better than the 04 lly winter warmup idle) and a stock, not butchered TCM.

[Whipped383]

Iv got the 03 with an 8.1. So I would need a completly different trans not just a valve body swap?

[Cougar281]

Iv got the 03 with an 8.1. So I would need a completly different trans not just a valve body swap?

The valvebody would work in the older trans as long as you also replaced the wiring and TCM, but it might be tough to get just a valvebody.

[Whipped383]

So whats involved in just modifying the valve body?

[Cougar281]

Not modifying - replacing. You'd have to swap in the 6-speed valve body (and associated solenoids), IMS (NSBU), wiring harness, external wiring harness that goes between the TCM, transmission, fuse box, ECM and I'd assume engine (not sure on the gassers)...

[Whipped383]

So what about using the TCM killerbee is selling? Its a modified stock TCM like the suncoast kit. I know someone mentioned the suncoast TCM has to use a modified valve body and not just a 6 speed valve body because the solenoids where different

[minytrker]

I have a 2003 duramax dually and will need a trans in the next year. Is it worth the money to upgrade to the 6 speed?

[Cougar281]

So what about using the TCM killerbee is selling? Its a modified stock TCM like the suncoast kit. I know someone mentioned the suncoast TCM has to use a modified valve body and not just a 6 speed valve body because the solenoids where different

Don't know. I haven't heard much about it so I can't comment either way. It may be better than Suncoasts or it may not. It probably does employ a modified VB as several solenoids are different between the 5-speed and 6-speed TCM & VB - which is why my truck never shifted quite right with the 6-speed VB being run by the 5-speed TCM.


I have a 2003 duramax dually and will need a trans in the next year. Is it worth the money to upgrade to the 6 speed?

That's a personal call. I wanted to ditch the FICM, get tap-shift, the enhanced winter idle, etc, so for me, I felt it was worth it. Overall, I'm very happy with my 2004 LBZ 6-speed :). PERSONALLY, I don't feel it's worth doing unless you go all the way and convert to all LBZ stuff. If you look in the right places, you may be able to do the entire LBZ conversion for not much more than the cost of the 6-speed conversion kits, especially if you sell the old parts. YMMV.

[motorhead540]

If you have a 01-05 DURAMAX truck with a 5 speed and want to make it a 6 speed, you are pretty well limited to the SUNCOAST kit. The 6 speed valve body will not just drop into a 5 speed and then have a 6 speed OS flashed in(tried this). You have to use the 5 speed style solonoids which means you have to run the kit. And if it is a 01-05 truck, there is no factory or ALLISON flash to enable 6th gear. If you have an 06-07 MD with a 5 speed, then yes it can be flashed to a 6 speed by ALLISON, or if you have a 8.1L you can swap in an 06 TCM, 6 speed valve body, modify the wiring harness, and have a 6 speed.


I have been considering purchase of a 2006 Topkick 4500 4x4 engine decodes as an LLY and guy says trans is a 5 speed you mentioned that 2006 MD can be flashed to enable use as a 6 speed who do I need to contact or what needs to be done to have this update done when or fi the get the truck

[killerbee]

I have been considering purchase of a 2006 Topkick 4500 4x4 engine decodes as an LLY and guy says trans is a 5 speed you mentioned that 2006 MD can be flashed to enable use as a 6 speed who do I need to contact or what needs to be done to have this update done when or fi the get the truck

For 06 and 07 MD trucks, it is not practical to simply reprogram your TCM, but we have a service that exchanges your 5-speed TCM for the 6-speed coded TCM you are needing. It is a straight forward swap process.

[protrac]

sent you an email for 6 spd TCM on my lly.

[Lennydmaxguy]

For 06 and 07 MD trucks, it is not practical to simply reprogram your TCM, but we have a service that exchanges your 5-speed TCM for the 6-speed coded TCM you are needing. It is a straight forward swap process.

Hey, killer bee, do you still offer this service? I need an al5 tcm with unlocked 6 speed calibration without core.

[killerbee]

Hey, killer bee, do you still offer this service? I need an al5 tcm with unlocked 6 speed calibration without core.

Yes, I have a few of these. You can use the email in my signature.