Automatic transmission manual mode stopped working

[stevsvws]

2017 JKU 3.6 Automatic. Rubi.

35’s and 3.73 gears. I know, need gears. Currently on a the list at a shop to get this done.

I was on the sand this week and the automatic manual mode would not work in 4wd. High or low range.

I always use low range on sand. But this time I could not get manual mode to
Work. It was stuck in D.

The sand was really packed down due low tide.

I thought I’ll go down there, put in 4 high and go. Still no manual
Mode. Ok was running fine but then I would push the pedal to the floor, revs did not get higher, just it would not go well.

10 minutes later.

I looked at temp of trans, 220 vs the usual 170 and smelling burning.

I put in neutral for a few mins, panicking as im in the area
Closer to the water and it’s low tide now. Great I’m stuck.

tThen into 4L, stuck in D, no manual mode, It worked fine and temps cooled down, lots of traction.

All worked well in 2 wd, towed a pop up camper home 120 miles. Manual mode just fine.

No lights no codes.

Trans service 5 k ago at 60 k.

Fluid didn’t look bad.

I did a fluid exchange today swapped out 4 qts.

Any thoughts. ?

 

[MacGuyver]

If you do a lot of sand driving, you may want to look into a separate radiator for the transmission. Especially with 35s on stock other stuff.

Also, I assume you have verified the 3.73 on a Rubicon? I didn't think that was an option for 2017, but I could be wrong.

It could be there is a lockout for gear select mode based on temp.

 

[stevsvws]

Thanks. Yes it’s 3.73, I bought it brand new in 17 and new this. Always has been fine.

I found my problem, the fluid was a little too full. I did it when I did the service a few months ago.

I removed 8 quarts of ATF, verified the fluid level, and all works well.

The regear is happening in the next month once the parts come in.

 

[Threepointsix]

If you do a lot of sand driving, you may want to look into a separate radiator for the transmission. Especially with 35s on stock other stuff.

Also, I assume you have verified the 3.73 on a Rubicon? I didn't think that was an option for 2017, but I could be wrong.

It could be there is a lockout for gear select mode based on temp.

I was recommended a trans cooler last summer by a shop when I went for a transmission fluid change. Was told (and found online) that heat is the enemy of all auto transmissions.