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Re Gear for Towing

Matthew Kashima

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Matthew Kashima Enthusiast

Matthew Kashima

Posted
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Hello, I have a 2014 Silverado that sadly came with the 3.08 gears. It is leveled with 33x12.50s, has a CAI and a cat back exhaust. I recently bought a 20 foot travel trailer and the 3.08 gears plus the tires just make it awful for towing. I was driving down the highway and it would rarely get out of 3rd and 4th gear. What would be the best gear ratio for towing and still having a good top end. I want 4.10s but feel my top end will be hurt.

Any advice is greatly appreciated. Thanks

mike221 Enthusiast

mike221

Posted
Posted

4.10s wouldn't be bad. If you're that worried about top-end, I would go with 3.73s

 

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GRN69CHV Enthusiast

GRN69CHV

Posted
Posted

Think you are answering your own question. Most I've towed with my '15 5.3/3.08 gear is about 4000#. It was happiest in 4th, was comfortable on flat level highway in 5th. Personally, I don't care to tow in deep overdrive 6th (.67 ratio) regardless of axle ratio, I think it just puts too much strain on the trans, opinions may differ. Doing some math, compared to 3rd in a T400 or 4L80E, 3.08 in 4th gear nets 3.54 final drive, 3.08 in 5th nets 2.62 final drive. 4.10 gear in 5th nets out to 3.48 final drive. 3.73 in 5th nets out to 3.17. If you're fixed on towing in 6th, then go to a 4.10 gear. Personally, I'd rather just plan on towing in M5 which will both keep it in 5th and V8 mode, so for me, 3.73 would be the best compromise for towing with the added benefit of still having a useable 6th gear for running the highway.

muddkatt Senior Enthusiast

muddkatt

Posted
Posted

4.10s wouldn't be bad. If you're that worried about top-end, I would go with 3.73s

 

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Top end speed will not be affected by either gear ratio if the truck still has the governor set at 98 MPH and then reprogrammed for the gear change and tire size. With the overdrive transmission, you would have to gear the truck into the 6.xx to run out of motor before hitting 98 MPH.

Matthew Kashima Enthusiast

Matthew Kashima

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Any idea what RPMs I would be at if I swapped in 4.10s at 70 MPH? also wondering how bad my MPGs would drop. I average 14.2 currently.

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