8 speed issues with z71 vs non z71

rdmsyr · October 8, 2020

I was wondering if the 5.3 / 8 speed transmission issues are more prevalent with the Z71 package or without?

Does it make any difference ?

bjr2020 6.2 · October 11, 2020

Depending on yr I believe there was a service bulletin to have a diff fluid added to help. But I don’t believe z71 option or not would matter to the issues.

rdmsyr · October 12, 2020

Yea - I heard about the transmission fluid.

i searched the forums trying to deduce if the Z71 vs non Z71 made a difference but no luck. I’m looking at a few trucks and it really doesn’t matter to me if it has the Z71 or not - I was just trying to stack the deck in my favor.

thanks

bamorris2 · October 12, 2020

I have a 2019 X31 (GMC’s version of the Chevy Z71) with the MQE 8-speed. No issues after over 9,000 miles.

2016 Sierra Owner · October 12, 2020

10 hours ago, rdmsyr said:

Yea - I heard about the transmission fluid.

i searched the forums trying to deduce if the Z71 vs non Z71 made a difference but no luck. I’m looking at a few trucks and it really doesn’t matter to me if it has the Z71 or not - I was just trying to stack the deck in my favor.

thanks

Stacking the deck in your favor would be to look at a truck with a 10 speed!! Hence the reason I had to get a 4wd just to get the 10 speed. I did my homework and decided I wanted to stay far away from the 8.

rdmsyr · October 12, 2020

Agree that the 10 speed would take care of the concern but was trying to save some $$$ with the 8 speed.

bjr2020 6.2 · October 12, 2020

2 hours ago, rdmsyr said:

Agree that the 10 speed would take care of the concern but was trying to save some $$$ with the 8 speed.

What’s the price diff to go the 10 speed vs 8? GM from what I’ve read has the 8 speed dialed in way better then my 2015 was but easiest way to go might be 10 speed if you want to be sure. 10 speed in my truck has been spot on under normal driving has alil shift issue after you get on throttle and let off but that might be the way there programmed not sure. My 8 speed after a flush to new fluid and I hptuned the slip tables it was spot on as well though too.