: Tranny Software Update



Bikedude
08-01-07, 11:24 AM
Just had the "chuggle" mod done to my 05 V8. What a difference it makes. Like others have said,"It now shifts like a caddy should". Thanks for the info on a great Forum.

throhrer
10-29-09, 12:22 PM
Has anyone noticed any difference in the gas mileage after doing the transmission software update.........talking about the 2005 STS4 in particular.

Thanks,

Tom

bierman.d
10-29-09, 10:18 PM
Nope--it should be the same.

throhrer
10-30-09, 11:29 AM
Just by chance did GM.....Cadillac..........have the factory fuel set lean for better mileage and that is what is causing the Chuggle and doing the up-grade to solve the problem could have set the fuel richer to eliminate the chuggle and this was a fuel releated problem all along and not transmission related???...........Just a thought. Was talking to a guy yesterday with a Ford F250 that was sent a bulletin from Ford to have the same kinda problem fixed with a re-flash and after he did, the fuel mileage lowered my 3mpg....he wanted it changed back and was told after you re-do it it can't be put back.


Thanks,

Tom

bierman.d
10-30-09, 03:07 PM
Interesting thought--but it's most definitely transmission related.
If I were you, I'd go ahead and get the update :) No noticeable change in performance or efficiency.. only a smoother drive.

throhrer
10-30-09, 07:24 PM
Thanks, I think I will

Tom

EChas3
10-30-09, 08:26 PM
Interesting thought--but it's most definitely transmission related.
If I were you, I'd go ahead and get the update :) No noticeable change in performance or efficiency.. only a smoother drive.

From some of the older threads, I got the idea that the TCM upgrade also increased the tendency of the transmission to shift-up while coasting at slow speeds. I like the way my 2006 AWD (5-speed) holds the gear and keeps the converter clutch engaged when coasting at slower speeds. When I stomp on the gas, she flies.

My wife's 2007 RWD has the 6-speed. It seems to seek the highest acceptable gear for any speed. When you stomp the gas, it has to downshift more gears. It doesn't seem as quick but this could be an illusion.

I know the mileage differential is bigger than I expected (5 MPG). I think it is the sum of 300 lbs more weight, more mechanical resistance (two more differentials & CV joints), lower gearing, an extra gear and the TCM program.

jwwkz
11-03-09, 08:39 AM
Can you direct me to information about the "chuggle" mod?

EChas3
11-03-09, 10:22 PM
Can you direct me to information about the "chuggle" mod?

See the 'sticky' thread at the top of the thread list.

bbshriver
01-26-10, 10:08 AM
Does this apply to 2wd STS or only the AWD? My car seems to do this some too, not really sure if it's just the "way it is" but the TSB sounds promising.

Mephy
01-26-10, 10:22 AM
The Sticky says STS4.

bbshriver
01-26-10, 10:44 AM
I see that, which is why I posed the question of whether anyone has had this on a 2wd. From what I understand they had the same transmission whether RWD or AWD so I would think it would apply to both.

M.A.C
01-26-10, 02:36 PM
Is the trans software update free? If not, how much does it cost?

LAC_STS
01-26-10, 03:08 PM
Is the trans software update free? If not, how much does it cost?

ewill3rd may know better but I had it done under GMPP warrenty because I went in there complaining of "chuggling" and there is a TSB about it. I think it should be an hours labor at most though if you had to pay for it.