1st year for the 6 liter and 6 speed for a 2500 chev

Thanks everybody.

chevman

A trucker friend insisted his Ford Taurus station wagon had a 5 speed, but it really had a 4 speed and lockup torque converter. Sometimes folks watch the tach and think it shifted when all that happened was the TC locking up..

larry barnhart wrote:
Neighbor feels he has a 5 speed in his 2001 GMC 2500. I don't feel it does but I forgot when the 6 speed auto arrived for the 6 L gas engine. Not for 2001 but it was later??

chevman

If he has the 8.1 BB then it has the Allison 5-speed. Otherwise if its the 6.0 it has the 4L80E 4-speed.

Technically, 2007.5 model year is when GM started mating the 6.0L to 6-spd transmission (6L9E). GM delayed the launch of GMT900 a little and still produced the GMT800 as 2007 Classic with 6.0L/4-spd.

GM mated a 5-spd (Allison 1000) to the 8.1L and Duramx in GMT800 pickups. Maybe that is his confusion. Or maybe he thinks the torque converter lockup in 4th gear is an actual gear change.

I believe 2007 is the first year the 6 speed 6L90E came out behind a 6.0 gas in a 2500...probably in the NNBS Silverados.

Mine is a 6 speed, 2007, 6 L. Silverado. I believe the 6 speed arrived with the new style 2007s.

larry barnhart wrote:
Neighbor feels he has a 5 speed in his 2001 GMC 2500. I don't feel it does but I forgot when the 6 speed auto arrived for the 6 L gas engine. Not for 2001 but it was later??

chevman

It is a 4 speed. I think it was 07 or 08.

Is here sure it isn't an 8.1? That had the 5 speed Allison.