Gear change?

Brandon32689 · November 2, 2014

I have a 14 gmc 5.3 I tow mine enclosed trailer to the dunes and it had some trouble I will be moving to a diesel sooner or later. But for know I got this total weight is prob 6500 lbs.

What's required to get new gears I have 3.42 I'd like maybe 4.10 would ot make much difference and will it void warrinty

Thanks guys

seansharley · November 2, 2014

I would say 3.73, unless you've put on larger than stock diameter tires, then 4.10

servantsalesmen · November 2, 2014

Personally, I think 3.73 would be good for your setup. 4.10s would be great but they would murder MPG's. As for the warranty, I don't think a gear swap voids it but I could be wrong. I suggest 3.73 over 4.10 just because the 3's are a factory option for half tons and gm may not like seeing a higher gear than they offer stock.

Brandon32689 · November 2, 2014

Okay would I notice much just from 3.42 to 3.73

servantsalesmen · November 2, 2014

Everything I have read says yes. Big difference. I have a 2000 suburban with 203,000 miles with 3.73 gears and it pulls hard. Even used it to tow a bobcat once. 3.73 gears are great. Bobcat was about 8,000 pounds when all said and done.

Also if you want, you could go to a dealer and find a truck with 3.73 gears and take it for a test drive to see for yourself.

fondupot · November 2, 2014

With the 6 speed trans its not worth jumping from 3.42 to 3.73. Got 4.10

Spurshot · November 2, 2014

Assuming the OP has a 6 speed and is using the tow/haul mode. If there is still a problem, the load may be much heavier than estimated if the truck is otherwise healthy. A 355hp 5.3L 3.42 6 speed should pull 6500lbs just fine unless you put 34" tires on it. If you put large tires on it, you may want those 4.11 gears.

Brandon32689 · November 2, 2014

I have the 6 speed Transmission.

The trailer is a 8.5x20 foot plus the v nose empty weight is 3200 lbs all I have in it is a few ice chest tools and a rzr so 6500 tops. I've tried tow haul and no tow haul. And it still pulls like crap. I have ro stay 60-65 MPh topps to keep it under 3k rpm if I try to go 70-75 it will go to 4-5 rpm and sound like trucks going to blow up fuel mileage goes to like 4mpg. It's all stock 15k miles on the truck. I've even tried going in manual mode.

Is it normal to switch to manual and it shows I'm only in 3rd gear I switch gears but truck don't act like it's switching.

I have to usually get it to shift by review it up and see the rpms. Drop.

I thought maybe it's the big trailer. But I maid a 450 mile trip 2 weeks ago to oklohoma to get this rzr and carried a 14 foot flatbed. Got 17 mpg up there and with a empty rzr weighing 1600 lbs it dropped to I mpg home and rpm all over place like it never can stay in a gear.

I am distributing the weight as best as I can and o have a equalizer hitch

redwngr · November 2, 2014

Okay would I notice much just from 3.42 to 3.73

FWIW, Duramax's are ALL 3.73's.

Rear end ratio's were not changed when they added the taller ratio extra gear to the Allison.

Brandon32689 · November 2, 2014

I need a duramax

kstruckcountry · November 2, 2014

Well the easy solution is let it run 3000 rpm, lock it down to 4th gear and go. You'll get better mileage than having it constantly shift.

Brandon32689 · November 2, 2014

Well the easy solution is let it run 3000 rpm, lock it down to 4th gear and go. You'll get better mileage than having it constantly shift.

That's what I usually do. But that's only going 60 MPh usually 65 max that's fine and all. But still only average 7 mpg.

olegachevy · November 3, 2014

I too have the 3.42 gears. I have a 2WD Crew Cab. So far, I haven't had any issues towing my Nash 25-C travel trailer which weighs around 7000-7500K when I load it up with gear. I keep my speed below 62 mph at all times for safety reasons, and do my best to keep it at 59 mph. On level roads, I have been averaging around 11 mpg at 59 mph. I have found that most of the time when I increase the speed to 62 mph, it drops to 8-10 mpgs.

Tows much better than my '04 did for sure. I still haven't towed in the mountains, so I may be looking to change to the 3.73s too if it gives me any fits in the hills.

Brandon32689 · November 3, 2014

I too have the 3.42 gears. I have a 2WD Crew Cab. So far, I haven't had any issues towing my Nash 25-C travel trailer which weighs around 7000-7500K when I load it up with gear. I keep my speed below 62 mph at all times for safety reasons, and do my best to keep it at 59 mph. On level roads, I have been averaging around 11 mpg at 59 mph. I have found that most of the time when I increase the speed to 62 mph, it drops to 8-10 mpgs.

Tows much better than my '04 did for sure. I still haven't towed in the mountains, so I may be looking to change to the 3.73s too if it gives me any fits in the hills.

Yeah in west tx it's not mountains but defiantly hilly I may switch to 3.73 first and see if that helps any.