Cruise engagement with T56 swap in trucks?

[mjhoward]

I have a 05 chevy truck.
There are several of us truck guys that have swaped in the T56. More noticably on forums are guys like me that previously had 5 speeds are having problems with cruise not engaging in 6th. I have tried it as slow as 25mph and as fast as 110mph @ 3000 rpms with no luck. I downshift to 5th at the same speeds and it will engage. 4th and 5th will engage cruise at ~25mph.

I have had no problems getting the proper info in HPT to get the speedo to work correctly with the 17 tooth reluctor wheel vs the 40 tooth that was in it.
The only plugs going into the trans is the VSS and the reverse light switch. The computer has no way of distinguishing mechanical engagement of 6th gear.
Any of you guys know about what makes the cruise function tick in the computer and how to correct it?

[mjhoward]

Ok, let me simplify this a little:

The trans has no outputs that would allow the computer to differentiate between gears. It will engage in 4th and 5th but not in 6th at any speed or rpm.

Is there some other criteria input into the computer that must be met to allow cruise to engage such as MAP, VSS pulses, TPS etc?

[mjhoward]

HELP!

[RERICK]

Someone be kind enough to help out on this , as there are several of us that have this problem, ME included .
Ron

[orange ss]

has to be something VSS related then, since speed doesnt affect it..

[EC_Tune]

Probably need the trans segement from a 4.8L manual truck to make things happy but I'm guessing here...

[2xLS1]

Just a guess, but there is probably some sanity check the computer does with mph/rear gear ratio/rpm to tell the cruise it is OK to engage. When in 6th, you are outside of what the computer thinks is a normal rpm/mph range since the 5 speed didn't have that .5:1 OD ratio. Again, just a guess.

[RERICK]

Probably need the trans segement from a 4.8L manual truck to make things happy but I'm guessing here...

Thanks for the replies . My truck was a 4.8L with 5spd. from the factory. The cruise works in 3rd. and 4th.. I want to get it to work in 5th. and 6th. . The trans is out of an 05 or 06 SSR. I think I need something from an SSR tune or maybe a GTO.
Thanks Ron

[RERICK]

T.T.T. Doesn't anyone know what makes the cruise tick ?

[mjhoward]

Thanks for the replies guys. I'm kinda with 2xLS1 on the sanity check issue. A couple of times i've actually seen the cruise light flicker when I tried to turn it on in 6th.
Can someone from HPT tell me if you can create a custom operating system to correct this issue?

Or what about doing a full re-write with a M6 F body file and starting over with the tune so to speak?

[2001CamaroGuy]

ttt......please help

[Bill@HPTuners]

Probably need the trans segement from a 4.8L manual truck to make things happy but I'm guessing here...

ttt......please help

Thats likey your anwser.

[CashDudeHomie]

He said in the first post that his truck came with a manual

Maybe you need a trans segment from a 6 speed car?

[Dark4Watch]

I know this is a very old thread but I got it figured out on my truck I did a 2005 cstv segment swap and now it works in all my gears .