TJ Manual to Automatic Swap

[rholbrook]

Besides the obvious transmission, what would be needed to swap the manual transmission out of a TJ and put in an automatic transmission? It as simple as just swapping out the transmission or does it need the computer changed as well?

 

[Silly Willy]

Lol Im looking at doing the opposite to my Cherokee

 

[jdub]

I believe it is a computer swap too.

 

[TJustin]

If you put the TF999 in, there isnt computer changes because the tranny doesnt need electronics to shift etc...

if you were to do an AW4 swap for example, you would have to do some wiring changes, and thats actually swung my decision to get keep the NV3550.

 

[jdub]

Is it because the motor behaves different with an auto? Will there be idling issues and running issues due to the increased draw that the auto's have?

 

[TJustin]

Is it because the motor behaves different with an auto? Will there be idling issues and running issues due to the increased draw that the auto's have?

No, the reason behind it is if you install an AW4, its all computer controlled. The shifter is electronic, and needs a computer to tell it when to shift. From what I have seen you need to do some pretty heavy splicing to the wiring harness and that turned me off.

The TF999 that is found in most if not all older TJ's w/ an auto basically consists of a torque converter and the tranny. The shifter is a linkage cable that connects to the transmission. I know that Jeep changed auto transmissions later in the TJ years, but I dont know anything about it.

 

[Mope]

Keep in mind there is no overdrive in the TF999 like there is in the AW4.

 

[waynehartwig]

Not sure about all years TJ, but my 04 had the harness in place for the auto - look at the back of the motor on the firewall. On mine I had two connectors there. One went to the motor and the other goes to the auto trans. So a simple computer change and add the auto trans pigtail and you should be set.

 

[TJustin]

Just for curiosity, what tranny came in the later TJ's? Its a 4 speed right?

 

[waynehartwig]

Just for curiosity, what tranny came in the later TJ's? Its a 4 speed right?

42RLE I believe and yes, 4spd

 

[Silly Willy]

If you end up swapping yours out I would be interested in taking it off your hands.

 

[waynehartwig]

I'd rather have an AW4 than a 42RLE..... The 42RLE has issues with loss of drive when on fairly extreme angles. The AW4 does as well, but there are deep sump pans that will solve that issue.