Do I need a trans tune?

[05Monsterdmax]

Long story short, sold my built motor and everything with it minus the tranny/rearend that's built. Put a lmm motor back into my 05 lly, stock fueling, and decided to go back lb7 turbo instead of the vvt. Also kept my technicooler. Trucks only used to haul my camper/boat now. Not sure if it's bc my trans tune is for a 05 or what but with the lb7 turbo my trans never seems to be in the correct gear when towing backroads. Always lugs out and takes forever before it down shifts then wants to scream. Does fine unloaded tho. Lb7 trans respond properly from all that I've drove which is why I decided on the lb7 turbo setup. Should I get a trans tune or just get a tapshifter? If trans tune who is the best on them? Trucks running ppei tuning currently, but stock trans tune. Thx

 

[DaJokr]

Must have to do with the TCM, because the trans all have the same gear ratios. That's all I can think it could be.

 

[LWATSON]

A trans tune will help your issue allot. I modified mine so it takes less throttle to downshift.

 

[THEFERMANATOR]

I like the 01 TCM OS, but modify the 4-5 tow haul shift to match that of the 02-04 LB7 trucks. The LLY OS is designed to lug the engine alot more since the VVT makes more boost down low than the standard wastegated turbo of the LB7 does. If you have EFILIVE(I'm guessing you or whoever tuned your truck does since your not running a VVT), and have your TCM flashed to an 01 OS. Or try the 02 TCM OS as it has MUCH more aggressive grade braking. I could get it to kick in even down here in flat Florida.