Chevy Silverado and GMC Sierra Forum banner

do i need to re gear?

2K views 11 replies 7 participants last post by  AJMBLAZER 
#1 ·
so i just put 35's on my truck with a 4" fabtech spindle kit. i have a 21' travel trailer that i tow often. i know my GVW rating is 6,800lbs and my trailer is approx 5,100lbs. but with 35's and the lift, should i regear?
fyi. my rear axle is 3.42 ratio.

thanks guys.
 
#2 ·
I would. It's probably already on the sluggish side. Add a trailer to that and it will be a real slug.

I'd go like 4.10 at least. Maybe 4.30. Since you said you tow often, 4.56 probably wouldn't be a bad choice either
 
#6 ·
I believe it is the number of times the motor makes a revolution compared to one revolution of the axle. So, with 4.10 gears, the motor would make 4.1 revolutions to make your wheels turn one time.
 
#9 ·
19trax95 said:
Close, it's the number of times the input rotates compared to the output.

So for 4.10 ratio, the input of the diff would turn 4.10 times for the wheels to make 1 rotation.
Oh, yah, I forgot about the transmission in the middle of the whole mess. Thanks trax
 
#10 ·
esox07 said:
I believe it is the number of times the motor makes a revolution compared to one revolution of the axle. So, with 4.10 gears, the motor would make 4.1 revolutions to make your wheels turn one time.
It's how many times the drive axle turns to one wheel hub rotation. 4.10 means, the drive-shaft makes 4 point 10
revolutions to every one wheel revolution. It does effect engine RPMS, but the engine, even at idle, is making way
more than 4.10 RPMs over the drive-shaft.

I went from 2.87 to 3.64 with my Dodge Charger, and I had to get a tuner to put in the new gear
ratio, else the trans goes in limp mode for engine over-speed.

My RPMs at 80MPH used to be 2800, now it's 3000. I still get 25MPG with a tune.

Changing the gears in the rear diff is not easy, it's easier to replace the whole rear
axle that has 4.10s already in it. If you have a 4x4, then you need to do the front
differential too. IT will cost more money doing gear swaps, than axle swaps, because
of the time it takes to remove and install the ring and pinion gear, plus the shimming
and play adjusting.

For the Dodge LX, LC, and LD platforms, the carrier (differential) is an easy swap, but
you won't be as lucky. I have 2 bolts and a damper bolt, lower it , angle to pop the axles
out, and then remove it. Installation is reverse, and takes 2-4 hours depending on
experience.
 
#11 ·
well im about to tow my 21' travel trailer today with 3.42 gears. will let ya'll know how it went. i did put in 91 octane with a 'tow' tune from my superchips. also made the tune 3.42 gear and tires 33".

do i need to push that 'haul' button on my shifter when towing?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top