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3.08 rear end questions

A.J._Langholff

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A.J._Langholff Enthusiast

A.J._Langholff

Posted
Posted

If someone else has already answered this question on here I'm sorry in advance, but I couldn't find it.

 

Ok i have a 2015 silverado crew 5.3 with 3.08 rear end love the truck so far. Was planning on lift & level in the near future but was wondering how 33 inch tires & a 3.08 rear are going to work? My dad has a 2014 with 3.56 rear end & I can notice a little more torque with his truck.

I don't pull a trailer much maybe 4x a month at the most...

a7519fd0c185f33708e4ae7ffb8a297f.jpg

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ZXTOM Enthusiast

ZXTOM

Posted
Posted

It will probably be ok, but I wouldn't pull any trailer with significant weight behind it, you'll just tear up your transmission, in the long run..

HondaHawkGT Senior Enthusiast

HondaHawkGT

Posted
Posted

I have 3.08's and 33's. I pull 15' flat-bottom + party supplies. Might weigh 1500 lb plus another 250 lbs in the bed. The truck has more than enough power. You might not like the shift points but as long as you have tow-haul on, that won't be an issue.

 

With a custom tune my truck feels faster with the lift and 33's than it did completely stock.

royrjs Enthusiast

royrjs

Posted
Posted

I'm running 35's with same setup, and already pulled a trailer of approx 4,500 lb; it's ok, you'll definitely feel a difference but it's nothing to die for. A re gear would be perfect but meh, engine and transmission are stout enough for what I do.

LongrangeLauber Senior Enthusiast

LongrangeLauber

Posted
Posted

I believe you meant to say 3.42's for your dad's truck, GM doesn't have a 3.56 gear for these trucks. I personally have 3.42's and tow often and just put on 33's. I can easily tell my truck struggles a little more than before and it killed my towing fuel economy, went from 10 mpg down to 6. And the torque is based off the engine rpm so the 3.42's keep it closer to peak torque in all gears which is why they are rated to tow more. You'll have the same torque at the same rpm just the 3.42's get you to that rpm sooner

VinnyZ17 Enthusiast

VinnyZ17

Posted
Posted

I have the 3.08s with 265/70/18s (32.6x10.7) P rated tires and the mpg suffered about 1.5mpg overall, which some of that is the 1in taller tire and no speedo recal. You can run 275/60/20 (33x11) P rated tires to keep from adding so much weight with a E rated 10 ply tire. I believe any 33x12.5 tire in any size is going to be a 10 ply tire.

Dan1220 Enthusiast

Dan1220

Posted
Posted

Vinny, can you post pictures of your tires? I too have the 3.08 and I'm considering 33" E tires. The truck is sluggish enough with stock tires, so it makes me nervous without re-gearing.

Georgia1911 Enthusiast

Georgia1911

Posted
Posted

... You'll have the same torque at the same rpm just the 3.42's get you to that rpm sooner

 

Same output torque from the engine yes, but less torque at the axle (3.08/3.42 or about 90%). Bigger tires, even if they weigh the same, will require more torque at the axle for a given rate of acceleration because of the bigger radius. You have a smaller lever working for you (the gears) and a longer one working against you (the larger tires).

Txjose Senior Enthusiast

Txjose

Posted
Posted

You will be fine.... I have 3.08s and 33s... Yah gas mileage suffers amd its a little sluggush..... But you get used to ut.

 

Sent from my Note 4 on Tapashit

LongrangeLauber Senior Enthusiast

LongrangeLauber

Posted
Posted

 

Same output torque from the engine yes, but less torque at the axle (3.08/3.42 or about 90%). Bigger tires, even if they weigh the same, will require more torque at the axle for a given rate of acceleration because of the bigger radius. You have a smaller lever working for you (the gears) and a longer one working against you (the larger tires).

I should have specified engine rpm
A.J._Langholff Enthusiast

A.J._Langholff

Posted
  • Author
Posted

I believe you meant to say 3.42's for your dad's truck, GM doesn't have a 3.56 gear for these trucks. I personally have 3.42's and tow often and just put on 33's. I can easily tell my truck struggles a little more than before and it killed my towing fuel economy, went from 10 mpg down to 6. And the torque is based off the engine rpm so the 3.42's keep it closer to peak torque in all gears which is why they are rated to tow more. You'll have the same torque at the same rpm just the 3.42's get you to that rpm sooner

Yeah your right my bad
Kerrslight Enthusiast

Kerrslight

Posted
Posted

I believe you meant to say 3.42's for your dad's truck, GM doesn't have a 3.56 gear for these trucks. I personally have 3.42's and tow often and just put on 33's. I can easily tell my truck struggles a little more than before and it killed my towing fuel economy, went from 10 mpg down to 6. And the torque is based off the engine rpm so the 3.42's keep it closer to peak torque in all gears which is why they are rated to tow more. You'll have the same torque at the same rpm just the 3.42's get you to that rpm sooner

 

From 10 to 6?! What are you running on vegetable oil or something? Lol...thats crazy to me. You've gotta mean while towing right?

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