How much of a difference between 8 speed and 10 speed?

[Homeslice]

The 10-speed equipped models sure seem to cost a lot more. But how much better is the 10 speed? Looking at MPG comparisons between the two, the MPGs appear to be basically identical. Maybe the 10 speed is more reliable/faster shifting/handle power better? Thanks!

 

[Big Mama]

The 8 speed ended up having some problems. I have a 10 speed in my Sierra 2500 and it’s fantastic. I haven’t owned an 8 speed. Are you looking at replacing yours or shopping for a rig? Will you be towing?

 

[Homeslice]

Thanks Big Mama! Looing for a new rig (haven't owned a Tahoe/Yukon/Escalade or anything like it in years). Was looking at a few different models. It looks like the 2007 to 2014 are at their max depreciation point, but the 2015 - 2020 or whatever models, while more expensive, sure look better to my eye. But then there seems to be a very big price gap between the 8 speed models and the 10 speed models. I remember the 8 speeds when they came out (I think in the Corvettes) having massive problems, but I was hoping those were mostly solved when they put them in the rigs. So I was curious on (i) how much more problematic the 8 speeds were in these rigs then the 10 speeds in general, and (ii) the performance advantages of the 10 over the 8 (and seeing that MPG appears to be unaffected, the acceleration, towing or other performance advanges).

In terms of towing, 99% of the time no towing involved. I might tow a motorcycle in the rare occasion. I really want it for safety (its big and comfortable) and to hop up the engine to make it a weee bit faster.

Thanks so much!

 

[Marky Dissod]

Looking at MpG comparisons between the two, MpGs appear to be basically identical.

Because the gearing is pretty close. Most 8L90s & 10L80s got 3.23 axles.
10L80 x 3.23: . . . 15.15 . . . 9.66 . . . 6.95 . . . 5.72 . . . 4.91 . . . 4.13 . . . 3.231 . . . 2.75 . . . 2.23 . . . 2.07 (7.38 Spread)
8L90E x 3.23: ...... 14.73 .... 9.60 ...... 6.72 ..... 5.46 ................. 4.10 ..... 3.231 ..... 2.75 ................. 2.10 (7.00 Spread)
10L80's 6th gear helps moreso for city MpG. 10L80's 9th gear is not as much of an advantage on the highway.
Can't speak to reliability or whether or not the bugs have been worked out for the 8L90.
The 10L80 is still young, but there is a rising tide of complaints about - and fixes for - the 'valvebody' (if I'm not mistaken).

 

[Big Mama]

The price gap you’re seeing comes from the refresh they did. If you can find one a great combo is the 5.3 and the 10 speed. There’s a recall for some 6.2 engine on the 14-19 years.