Let's not forget torque management, gentlemen. They put the 4L60/65/70E in lots of truck applications, and the only reason it lives is because they cripple it with TM. In my TBSS I would get whiplash between shifts, it was so hobbled at high HP & TQ levels.

Just because the 6L80/90E is in a high-HP application, does not mean it is strong enough to handle the job. They could be governing it such that you never even get to feel the 550HP (or whatever it is) at the input.

 

6L90's arent weak transmissions, they look VERY stout to me, very similar to an allison

 

Allisons aren't that strong till you build them, they will only take about 80 to 100 hp over stock till you burn up the C3 clutch pack. Better clutches and some valve body work and they are very strong though.

 

Ok, SO this is the response I got from PCS

 

yep they are cheap, i would like to get my hands on a dosen of these things and just hold on to them

 

Like I said, anyone who knows the ins and outs of these transmissions will tell you that the basic design of the 6L80/90E transmissions is weak. This is more proof.

With a 4L80E, you can run zero TM and run high HP all day and night, with no problems. If you plan on making lots of power, a 4L80E is the way to go.

 

Its the tuning that they are worried about burning these transmissions up, not the actual hard parts of it. Like I said, I have been in these trannies before, they look very stout. The design is not weak!

 

Ive seen a bone stock allison with 150k on it put 500 rwhp down and a **** load of torque, its the cheap *** programmers that burn the trannies up.

 

Have you been on thedieselplace.com much? I have since my dad bought his 03 (145k miles now). I put a mild tune, (via EFILive) probable +100-120hp (Stock tranny tuning, nobody likes to mess with those) and it would slip 5th gear and go into limp mode every time you rolled onto it hard on the highway, I had to back it down (+80 or so) till he can get to a descent tranny shop to get a SC level IV kit and new converter put in it. From what I have read over there, is the factory didn't give the C3 pack enough clutch or line pressure. They will hold 500 if you don't run them into 4 or 5th gear with that much power, but what fun is that, lol.

 

Yes I have, If your going to bump up the power 120 horses don't you think you might want to tune the transmission too?? That makes sense to me. And yes I am aware of the C3 clutch problems. I have seen pressure as low as 90 psi when C3 is commanded on. That will defently burn it up. If your not sure on the tuning of the trans, then get the ATS co-pilot.