45RFE for a 42RLE

[Her Jeep]

Is it possible to switch out the 42rle for a 45rfe in a 2011 kk 4wd. I would prefer the extra gears for fuel saving sake.

 

[jeeptorino68]

those transmissions have the same gear options. i think you mean the 545RFE? if you do it is the same as a 45RFE it just has a different program that adds another overdrive.

 

[tjkj2002]

Is it possible to switch out the 42rle for a 45rfe in a 2011 kk 4wd. I would prefer the extra gears for fuel saving sake.

How much money you have? Better off taking the couple thousand $$$'s needed to do the swap(mostly custom computer programming) and put it towards alot of gas.

those transmissions have the same gear options. i think you mean the 545RFE? if you do it is the same as a 45RFE it just has a different program that adds another overdrive.

The 42RLE and 45RFE/545RFE are 2 competely different trans.

 

[04Liberty]

those transmissions have the same gear options. i think you mean the 545RFE? if you do it is the same as a 45RFE it just has a different program that adds another overdrive.

Totally different gear spacing between those 2 transmissions. tjkj is dead on, you would have to spend a bunch of money to get it to work correctly. The 42RLE actually has a steeper OD ratio (.69:1) versus the 45RFE's (.75:1). Even when programmed out to the 545, the OD ratio is still only .67:1, marginally better than the 42RLE and not worth the effort.

 

[jeeptorino68]

is it worth it to get your 45RFE programmed to a 545RFE in the liberty with a 3.7? the 3.7 is pretty marginal...so less RPM on the highway wouldnt be much better...

 

[04Liberty]

is it worth it to get your 45RFE programmed to a 545RFE in the liberty with a 3.7? the 3.7 is pretty marginal...so less RPM on the highway wouldnt be much better...

It would only be worth trying to do (dunno if you can even do it with a KJ) if you went to say 4.10's and wanted the extra OD for highway driving.

 

[Her Jeep]

Okay it stays as is. Now i just have to add some other toys.