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8spd transmission w/ lift kit and larger tires

GraphiteSilveradoZ71
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GraphiteSilveradoZ71 New Member

GraphiteSilveradoZ71

Posted
Posted

I have a ‘17 Silverado 1500 Z71 4wd with the 8spd transmission.

I recently purchased 6” lift kit (not installed yet) and currently looking to purchase 35” tires.

 

I’m currently running a 2.75” level and 305/50R20 A/T tires, Carven cat back exhaust, and using a Diablosport intune i3 programer and have had no issues.


My question is, will running a tire larger than 33” cause any transmission issues? Anyone have transmission problems running 35’s? I know on the programer i can change the tire size to correct the trucks speedometer.

diyer2 Senior Enthusiast

diyer2

Posted
Posted

My 2 cents.

Bigger tires require more torque. More stress on the trans IMO. The reason re-gearing is done. 

In the ATV world adding bigger tires or mudding a lot requires re-gearing for best performance. 

My suggestion would be to service trans fluid more. 

shakenfake Senior Enthusiast

shakenfake

Posted
Posted

I agree but the 8 speeds have problems. Just cause you put on 35s doesn't mean you are going to blow a transmission

 

OP what gears do you have? You may find that with 35s you are going to want some more gear

diyer2 Senior Enthusiast

diyer2

Posted
Posted

I said nothing about blowing the trans. For performance and  longevity change gears and change the fluid more often. 

lucas287 Enthusiast

lucas287

Posted
Posted

These 8 speeds don't suck. Don't listen to the noise from people who don't have one, much less one that's properly tuned. It's a very robust transmission in reality and can take A LOT of abuse. 

 

Lift away my friend. Use whatever size tire you want. Like others have said, re-gear, or better yet, spend the money on a tune from someone that's a Gen 5 specialist. 

  • 2 weeks later...
pokismoki Senior Enthusiast

pokismoki

Posted
Posted

yeah the 8speeds have crazy torque gear ratio and you can get away with bigger tires on stock gearing vs 6spd.

 

they all have issues with stock tuning from GM, but after you get them dialed in they shift faster than 6 speed.  they're only draw back is the sheer mass of them sucks tremendous HP compared to the old 4L60e 

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