SHOW & SHINE DISCUSSION Appearance | Detailing | Wheels | Truck of the Month
Sponsored by:
Sponsored by:

3:90 Gears

Thread Tools
 
Search this Thread
 
Old Feb 1, 2021 | 08:08 PM
  #1  
ss4chad's Avatar
Thread Starter
12 Second Club
20 Year Member
Loved
Liked
iTrader: (19)
 
Joined: Nov 2005
Posts: 877
Likes: 41
From: Ft. Worth, TX
Default 3:90 Gears

So I will be going with 22's in all 4 corners. 22x9 front and 22x11 rear with 275/40 & 305/40. I am also putting my Yukon Positrac in the rear end and thought about adding 3:90 gears to it.
The factory rear end is limited slip with 3:42 gears.
Can you think of any issues with that? Will I have to have a "Rear End Tune" after the install?

Chad
Reply
Old Feb 1, 2021 | 08:13 PM
  #2  
FFDP's Avatar
TECH Senior Member
iTrader: (2)
 
Joined: May 2014
Posts: 5,282
Likes: 600
From: Rogers, MN
Default

I don't see a problem with that.

3.90's is better than 3.42's in many applications and yes you need to tune the computer for the gear change. The speedo needs to be corrected and the transmission needs to know the tire size and gear ratio for proper shift scheduling.
Reply
Old Feb 1, 2021 | 10:00 PM
  #3  
arthursc2's Avatar
TECH Veteran
iTrader: (5)
 
Joined: Jan 2014
Posts: 4,341
Likes: 1,517
Default

4.10 or bust
Reply
Old Feb 1, 2021 | 10:09 PM
  #4  
terravast4's Avatar
TECH Junkie
15 Year Member
Liked
iTrader: (25)
 
Joined: Jul 2007
Posts: 3,200
Likes: 347
From: Austin, TX
Default

Originally Posted by arthursc2
4.10 or bust
agreed
Reply
Old Feb 2, 2021 | 12:20 AM
  #5  
RedXray's Avatar
100% Redneck
 
Joined: Mar 2005
Posts: 2,098
Likes: 1,344
From: MAGA COUNTRY
Default

I agree 4.10's with the 31.6" diameter rear tires.

Yeah just add the tire height and gear ratio in the HP Tuners "Gear/Tire Wizard" and it scales all the parameters in the tune automatically

3:90 Gears-xm6wb2q.jpg
Reply
Old Feb 2, 2021 | 06:57 AM
  #6  
ss4chad's Avatar
Thread Starter
12 Second Club
20 Year Member
Loved
Liked
iTrader: (19)
 
Joined: Nov 2005
Posts: 877
Likes: 41
From: Ft. Worth, TX
Default

I figured the Speedo would be off but is ok to drive around for another couple of months before I get that "Tune"? I don't have HP Tuners, or any tuning software for that matter. I will be installing the gears in the next week or so but the tires & wheels won't be installed for another 4 - 6 months as CASH permits it.
With the new gears installed is the computer going to flip out because of the gear change and make it unsafe to drive? You mentioned 'Shift Scheduling', will it damage the transmission not having it tuned for a month or so?

Chad

Last edited by ss4chad; Feb 2, 2021 at 07:01 AM. Reason: Clarification
Reply
Old Feb 2, 2021 | 07:54 AM
  #7  
firebladeJJ's Avatar
TECH Apprentice
iTrader: (1)
 
Joined: Apr 2011
Posts: 395
Likes: 64
From: FTW
Default

I did 4.10 in my 2012 with stocker 20s, it raised the rpms over all by about 500...gas mileage didnt change one bit even down the highway, plus its quicker around town. if you change the gears and wait on the tune, your ABS light and dinger will hate you every time you start the truck and get rolling. Your ABS and Stabilatrak and Traction control will NOT work, when the lights are on the system will not work properly. If you want to pay for the credits, I can make the adjustment to your tune. I wont do any actual engine or trans tuning just the gear ratio.
Reply
Old Feb 2, 2021 | 08:11 AM
  #8  
ss4chad's Avatar
Thread Starter
12 Second Club
20 Year Member
Loved
Liked
iTrader: (19)
 
Joined: Nov 2005
Posts: 877
Likes: 41
From: Ft. Worth, TX
Default

Originally Posted by firebladeJJ
I did 4.10 in my 2012 with stocker 20s, it raised the rpms over all by about 500...gas mileage didnt change one bit even down the highway, plus its quicker around town. if you change the gears and wait on the tune, your ABS light and dinger will hate you every time you start the truck and get rolling. Your ABS and Stabilatrak and Traction control will NOT work, when the lights are on the system will not work properly. If you want to pay for the credits, I can make the adjustment to your tune. I wont do any actual engine or trans tuning just the gear ratio.
How much are credits? What are Credits? I'm assuming you would plug into my truck to do this, so where are you at? I live in Keller, about 8 miles South of the Texas Motor Spdwy.
Thanks for the reply!!

Chad
Reply
Old Feb 2, 2021 | 09:02 AM
  #9  
firebladeJJ's Avatar
TECH Apprentice
iTrader: (1)
 
Joined: Apr 2011
Posts: 395
Likes: 64
From: FTW
Default

I'll have to check on the price of the credits for the HPTuner License to make changes to your truck. yeah I'll have to plug in to the truck and mess with it, I'm in the Weatherford area. We met once before, I bought that rear sway bar off you a few years ago.
Reply
Old Feb 2, 2021 | 10:37 AM
  #10  
ss4chad's Avatar
Thread Starter
12 Second Club
20 Year Member
Loved
Liked
iTrader: (19)
 
Joined: Nov 2005
Posts: 877
Likes: 41
From: Ft. Worth, TX
Default

Oh yeah! How did the sway bar work out? Great I hope!
Yes, let me know about the HP Tuner thing and I will holler at you when I got the gears installed.

Chad
Reply



All times are GMT -5. The time now is 09:43 PM.