1999 TJ transmission swap from a 32RH to a 42RLE

[2traktj]

What issues will I run into doing a swap from a 1999 3spd auto to a 2003-06 4spd auto.... mounts? driveshaft length? computer/wiring? speedo plug in etc Looking for info

 

[Chris]

This is a downgrade. The 32RH 3-speed you have is superior to the 4-speed 42RLE.

 

[2traktj]

This is a downgrade. The 32RH 3-speed you have is superior to the 4-speed 42RLE.

Thanks! 20+ years ago when I looked for this setup (color, engine and specific 32RH (3apd) Life was different- with a gear swap I was looking to gain more distance driving experience (lower rpm/mpg) that’s all… was considering a manual also

 

[Chris]

Thanks! 20+ years ago when I looked for this setup (color, engine and specific 32RH (3apd) Life was different- with a gear swap I was looking to gain more distance driving experience (lower rpm/mpg) that’s all… was considering a manual also

I prefer the manual transmission on the TJ in every single use case except serious off-roading / rock crawling.

The TJ is much more peppy and fun to drive with a manual transmission. The automatic really shines when you're doing technical off-roading. I've owned both manual and auto TJs and I prefer the manual myself, but I'm also not a technical off-roader really.

If you're sticking with an auto though, the 32RH is considered the better option by most. The overdrive in the 42RLE is just a steaming pile of crap. Even when properly geared it still can't decide which gear it wants to be in.

Though in fairness I believe @MikeE024 and others have figured out how to modify the shift points via HPTuner. I've heard it makes a world of difference. Unfortunately I've never got to experience that.

If that is true though, then the 42RLE is probably a worthy upgrade. Just remember to put a transmission cooler (Setrab being a good choice) on it!

 

[MikeE024]

Thanks! 20+ years ago when I looked for this setup (color, engine and specific 32RH (3apd) Life was different- with a gear swap I was looking to gain more distance driving experience (lower rpm/mpg) that’s all… was considering a manual also

What RPMs are you hitting on the highway? I ask because you might not be revving high enough for there to be a concern.

Regardless, I likely wouldn’t go through the effort to swap a 32RH to a 42RLE.

 

[mrblaine]

What issues will I run into doing a swap from a 1999 3spd auto to a 2003-06 4spd auto.... mounts? driveshaft length? computer/wiring? speedo plug in etc Looking for info

If you are serious, contemplate that the most efficient path to pulling this off would be to purchase an 03-04 and then swap everything into the 99 to make it an 03. Complete wiring harness, TCM, Trans harness, PDC, etc. and then you would to convert from distributor to coil rail on the plugs to be compatible with the PCM, harness and the new cam shaft synchronizer.

Figure out what the cross body harness is to see if you can adapt the emissions to be in the rear corner or want to modify that harness to work with the emissions group under the hood.

There may be another way to do it, I ain't that smart.

 

[mrblaine]

Thanks! 20+ years ago when I looked for this setup (color, engine and specific 32RH (3apd) Life was different- with a gear swap I was looking to gain more distance driving experience (lower rpm/mpg) that’s all… was considering a manual also

Auto to manual swap is far easier and will get you where you want to be if you don't need the auto.

 

[Bammo68]

Swapping OUT a 32RH? Ewwww....