Re Gearing After Lifting - Need Some Education

[tommudd]

The 4 is a diesel, correct?

KJs came with a 4 cylinder gas as well for a couple of years
I added the models above to my post
CRDs in the US never came with 4.10s

 

[sleepyjim]

If you change the gearing (04 Liberty, 3.7) do you have to reprogram the computer?

Jim

 

[tjkj2002]

If you change the gearing (04 Liberty, 3.7) do you have to reprogram the computer?

Jim

No,gearings does not effect the speedo(or computer),tire size however does.

 

[ktmrider]

The speedometer is the only thing really effected with a tire change that I know of. Never heard of remapping a ecm after a tire change.

 

[604KJ]

I just went to the dealer 2 weeks ago to have my computer programmed for my tires. I didn't think it was necessary because I was only about 1"-1/2 over stock, but since I put them on the KJ was shifting very poorly/sporadically and struggled uphills. So I said what the hell lets try it. Now it feels like I have some power back, I can get uphills without it searching for a gear & haven't had any shifting problems since.(nobody knew what I was asking for when I called, went through 3 different dealers before one of them told me "oh, you want to program your pinion factor"

 

[nullptr]

I just went to the dealer 2 weeks ago to have my computer programmed for my tires. I didn't think it was necessary because I was only about 1"-1/2 over stock, but since I put them on the KJ was shifting very poorly/sporadically and struggled uphills. So I said what the hell lets try it. Now it feels like I have some power back, I can get uphills without it searching for a gear & haven't had any shifting problems since.(nobody knew what I was asking for when I called, went through 3 different dealers before one of them told me "oh, you want to program your pinion factor"

What was the procedure for this? Did you just have to tell them how many revolutions per mile on the tire and they encoded that to the BCM?

 

[604KJ]

What was the procedure for this? Did you just have to tell them how many revolutions per mile on the tire and they encoded that to the BCM?

Yes, then they said pinion factor.
1st dealer told me I couldn't do it with the Liberty
2nd dealer, only after I explained what I wanted done for a few min, wanted to charge me twice as much as dealer#3, who knew right away and was less expensive. (a lot further from home though)

I found out about this programming on this thread;
http://www.jeepkj.com/forum/520261-post75.html