My new 5.38's?
02-09-2012, 06:01 PM
#11
JK Enthusiast
Join Date: Dec 2010
Location: ATHENS , GEORGIA
Posts: 214
Likes: 0
Received 0 Likes
on
0 Posts
Your rig will perform better after you reprogram it for the gear change. The speedo is electronic and gets its feed from the trans so until you tell it what gears and tire size nothing will work like it should. Do the programming and you will love your jeep.
02-09-2012, 06:20 PM
#12
JK Enthusiast
Thread Starter
Join Date: Feb 2011
Location: Crown Point,Indiana
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for all the info guys. Yeah I will get chip to communicate with computer on gears to make the Jeep happy. Till then maybe I will try one of those phone apps or Gps to check speed reading.
02-09-2012, 06:37 PM
#13
JK Newbie
Join Date: Jun 2011
Location: Houston, TX
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
So I just went from stock rubi gears to 5.38's. Did the job myself. Everything seems good. Have 100 miles since job. Do I need to reprogram gear ratio. It seems like the speedo is correct. I did not change tires yet.
If the speedo is correct does it need reprogramed to shift differently or should that be correct also? Its a 2008 auto
If the speedo is correct does it need reprogramed to shift differently or should that be correct also? Its a 2008 auto
It all depends on how much bigger tires you are running. For instance, if you went up to a 35" tire, which is 12.9% increase in size from a 31" tire, and you had 4:10 gears stock you would need to have 4.60 gears. So depending what size tire you have, you might be ok.