GM 6.0/4sp vs. 8.1/Allison vs. 6.0/6sp
Hi all. My Towrig in Sig is getting a little long in the tooth. We just bought a New to us Toyhauler which is quite a bit heavier than our old trailer and my truck is hating life lol!! We were pla...
Forum Discussion
Paging Dick_B... He has experience with the 8.1L and now the 6.0L/6-spd. I believe his prior TV was a Suburban which did not use the Allison trans, but experience should be similar. I looked for an 8.1L Burb for about a year before buying a new 6.0L/6-spd. That is one strong engine.
Going to 6-spd with the 6.0L will feel quite a bit better. Take a look at this chart comparing the gearing and torque multiplication for the SUV 4-spd trans to the 6-spd. The Allison does a little better with a 3.1:1 first gear ratio. As far as I know, all pickups with 8.1L used the Allison trans and the Suburban/Yukon XL/Avalanche 8.1L had the in house 4-spd as Burbman mentioned.
So the newer 6.0L still likes to rev. It would still be singing or screaming at 5000rpm up some hills. The 6-spd will help get and keep the engine in it's happy range. You would probably end up spending most of your time towing in 4th gear as I don't know that it could hold 5th on flat highway. You need the 4.10 axle as the tow ratings for 6.0L/6spd/3.73 is in the 9500-ish pond range. 4.10 is about 12k until 2011 I believe which is near 14k pounds.
Honestly, at your 12k estimated weight, I would suggest 8.1L or the diesel you said you don't want.
Going to 6-spd with the 6.0L will feel quite a bit better. Take a look at this chart comparing the gearing and torque multiplication for the SUV 4-spd trans to the 6-spd. The Allison does a little better with a 3.1:1 first gear ratio. As far as I know, all pickups with 8.1L used the Allison trans and the Suburban/Yukon XL/Avalanche 8.1L had the in house 4-spd as Burbman mentioned.
So the newer 6.0L still likes to rev. It would still be singing or screaming at 5000rpm up some hills. The 6-spd will help get and keep the engine in it's happy range. You would probably end up spending most of your time towing in 4th gear as I don't know that it could hold 5th on flat highway. You need the 4.10 axle as the tow ratings for 6.0L/6spd/3.73 is in the 9500-ish pond range. 4.10 is about 12k until 2011 I believe which is near 14k pounds.
Honestly, at your 12k estimated weight, I would suggest 8.1L or the diesel you said you don't want.
