My '89 XJ has an AW4 automatic transmission. The shift position indicators are laid out like this...

P
R
N
D
3
1-2

It's that last part that has me stumped, the 3, 1-2 part. Since, if I put the transmission in the 1-2 position, logic would dictate that this would allow the transmission to operate only in first and second gear. However, with the transmission in this position, it only operates in first gear and will not shift into second until I move the lever into the "3" position. Shouldn't the indicator panel read...

P
R
N
D
2-3
1

As far as I can tell, 2nd gear is not available in that last position... or is there something wrong with my transmission?

 

I never had an AW4 but I recall that they shift via pressure shift from 1-2 at 4k RPM. But I could be thinking of something else entirely. Someone else?

 

I've never really played around with my shifter before. I'll have to try it after work

 

Hey there F1. I went through a bit with this since I wanted 2nd for going 3 mi down 1,500 feet. It will use 2nd going up, accelerating. In decel, mine will stay in 2nd until I drop below about 33 mph, then "hit" first. No fun! (got part of a stump stuck in my rack once).

There is a link here in post #19 with yet more....https://www.cherokeeforum.com/f2/dec...105739/index2/

 

My old XJ would not want to stay in 1st and shift immediately to 2nd, which was annoying when I wanted 1st to engine break.

 

The AW4 is controlled by the ECU, You can run a switch to allow for 2nd gear when necessary. Otherwise, what others have stated is correct.

 

Okay, that is certainly possible. I've never run it beyond ~3K RPM in the 1-2 position. One of my biggest issues will be traversing steep mountain passes, one of which is 12 miles long and descends at a 13% grade (with a several thousand foot drop if things go wrong). Even with high performance brake rotors and pads and braided lines, brake over-heating and fade are unavoidable without engine braking. 1st gear would be far too low and third would be way too high, 2nd would be optimal but I just can't figure out how to access 2nd gear.

I know, I know, buy an AX15 equipped XJ. That's not an option for me right now.

 

I posted a thread on here about the same thing. They said that it will shift at redline, but I'm not gonna try and possibly blow my 233k engine. Best option in my opinion is to put a switch. Anyone know how to do that?

 

Decelerating above 35 mph (stock), in the 1-2 position, it should be in second. You don't get allot of braking from it until your 40 ish +. With my switch I can set it so it wont kick down on it's own to first when I slow down.
You can set it to stay in first, just with the shifter.

I found my bucket of saws-all blades looken at that thread!

 

I'm not worried about redline, although I do try to avoid revving it that much. However, for engine braking it may be problematic if 2nd gear slows it down enough that it selects 1st while going down a very steep grade with several thousand feet of free air just feet to my right. I'd love to know more about this bypass switch... I assume it's wired to the TCU in order to create some sort of 1st gear lock-out?

40-45 MPH would be ideal for the descent, I just need something that will supplement the brakes since I may be doing this pass several times a day over the summer. It's a well-maintained two lane road with only a couple hairpins but it's severely lacking in guardrails, an omission that has, over the years, sent several people to wherever their maker though appropriate. Also, there are frequently rocks on the road, from pebbles to stones to car-sized boulders that need to be avoided.

 

Just got back from going to the store and can confirm, it does shift to 2nd at redline (~5000 RPM) and holds it down to about 30 MPH before dropping into 1st again. The downshift was very smooth, by the way. I was ready for something that would suck my eyeballs out of my head but it was rather undramatic.

Still hoping someone will find a link to the 1st gear lock-out switch. I've been googling with no success.

 

Flintstone did this mod. He'll post it up for sure.

 

Holy freakin' crap, I love the internet... and this dude from Australia who not only has a very good write-up on the 1st gear lock-out but also a full schematic for converting your AW4 to a full tiptronic-type manual with the flip of a switch.

http://go.jeep-xj.info/HowtoAutoSwitch.htm

 

Go-Jeep has good stuff on his site, huh?

 

I think so. Lot's of fairly original ideas and fabs and they all seem well executed, not kluged together with packing tape and a paste stick. Plus, that AW4 tiptronic mod. If that works... wow. I'm gonna try.