Hey all....

Well it looks like my transmission for Red has finally given up the ghost after 297k. I've read before that replacing the TCM with one from a Jeep Grand Cherokee (think it was from the GC but not 100% sure\) would enable the 45RFE trans to mimic the 545RFE. Question that I have is it possible to swap both the 545RFE and the TCM (from a Jeep with the 4.7L engine) to a 2000 Durango 4x with the 4.7L engine or will that fubar the ECM? Leaning heavily towards just keeping the 45RFE unless I can score a good deal on the 545RFE and TCM.

Thoughts? Would there be any detriments to doing this swap?

Thanks in advance,

Steve

 

To heighten your search options.... you should also look at the Dakotas like mine as they have the 545RFE and TCM. They will probably be more of a guaranteed fit due, to possibility of any physical nuances with the Jeep tranny.

 

My understanding is the 45rfe and 545rfe are the same. The tcm/programming to use the extra od is what makes the trans a 545rfe. The tcm swap did work on my mom's 02 liberty with no problems.

 

Did she see any improvement in driveability, fuel economy, anything at all??

 

She didn't have the thing very long before I did that to really compare fuel economy. I bought the thing last summer as a project and fixed it up and gave it to her and put that control module in not long after. You could definitely tell it turns lower rpm on the highway (I forget exact numbers, but maybe closer to 2000 instead of 2300 or so at 60ish on the highway. Doesn't seem to bog down the 3.7v6 in it either. Again I haven't driven it a ton since doing that, but it seemed to me like it pretty much went from 4th to 5th right away after the 3-4 shift, didn't seem to me like it would really hold 4th for long.

They've taken it to Florida and Tennessee since and got about 19-20mpg with it from what I recall. It's a 2002 limited rwd.

 

Interesting. I just picked up a 2010 liberty sport for the wife, and she drives all over gods creation. Getting better fuel economy would be good for her wallet.....

 

I think after 02 they may have only put the 45/545RFE in the diesels though, I think 03+ was the 42RLE for the gas engines. I also bought an 05 renegade at the same time to fix up and it had the 42RLE. No extra gears to be unlocked in that trans.

 

Do you know what year Dakota's had the 545RFE with 4wd?

Thanks in advance.

Steve

 

I know my 03 with RWD has it. Not too sure about 4WD. The "R" specifies rear wheel drive but I believe it was also used on 4WD model.... but just with a different output shaft. Read thru these...

https://dodgeforum.com/forum/3rd-gen...nsmission.html

https://www.allpar.com/threads/the-4...d-rams.230023/

 

The extension housing is different between 2 and 4wd but I think you can swap them.