Tranny gear switch mod problem

Today I tried the mod that allows you to keep the tranny from shifting out of 1st/second on my '88 XJ auto tranny, using Billvista's directions, which say to cut the yellow and wire it to the a & b posts, while the "c" post goes to ground. I did this ground by just grounding it to the chassis. (Initially I
grounded it through the light in the shift indicator, but same result.)

All I seem to get is third gear only (maybe second?) in both settings of the switch, but it's hard to tell. BTW, I actually soldered my connections, so I'm fairly sure that is not the issue.

I have not tried to bypass the mod to see if restoring it makes the tranny work right, or not.

Any suggestions as to what I may have done wrong?

Billy

PS, I noticed that my oil pressure guage is reading off the charts now too, so I may have messed something up... :doh:

Compare it to my write up as it does not sound the same to me???

http://go.jeep-xj.info

Gojeep said:

Compare it to my write up as it does not sound the same to me???

http://go.jeep-xj.info

Click to expand...

That's correct, I used a plan laid out on P.O.R. Yours uses a tie-in with the purple/white wire, while the one I was using just cuts the yellow wire in half, attaches it to two of the three posts on a two-setting switch, and the third post on the switch goes to ground.

Yours, I believe, (not sure, really, since I've read several different versions) requires a three-position switch (on-off-on). I read your explanation of your mod, and it was not quite basic enough for my non-electrical-thinking mind, so I tried the other one (which I could follow...)

This is the one I followed, but either I've done something wrong, or it doesn't work properly on my tranny.
http://www.rightcoastcrawler.com/billaVista/trannyswitch/auto-man_switch.htm

this is how bill's setup works:

when power is cut from the TCU, the aw4 will not shift on its own, you end up with a 3-speed manual via the shifter (1,3 and OD are the accessible gear ranges)

you put the stick in the 1-2 position, it goes to 1 and stays in 1.

by grounding the yellow wire, you most likely blew the inline fuse for the TCU.

bill's wiring either turns the TCU on, or it turns the light on.

change everything so that your wiring is EXACTLY how Bill has it per the writeup, and then check your fuses.

racer122 said:

Today I tried the mod that allows you to keep the tranny from shifting out of 1st/second on my '88 XJ auto tranny, using Billvista's directions, which say to cut the yellow and wire it to the a & b posts, while the "c" post goes to ground. I did this ground by just grounding it to the chassis. (Initially I
grounded it through the light in the shift indicator, but same result.)

Click to expand...

just to point out where you may have went wrong, the reason he had a ground hooked up was for the LED indicator he hooked up, not to ground the yellow wire (DO NOT DO THAT!!!)

CheapXJ said:

just to point out where you may have went wrong, the reason he had a ground hooked up was for the LED indicator he hooked up, not to ground the yellow wire (DO NOT DO THAT!!!)

Click to expand...

OK. But my switch has an internal light, and so I did not need to wire an indicator light through the switch. So, what would the third spot be for? Anything? Or, since it is only there to indicate the yellow wire connection is broken, leave it empty?

Oh well, if I blew a fuse, no biggie. BTW, I ran an inline fuse on my yellow-wire lead too, just to be safe. I'll have to check that too (but I didn't smell any fuses blowing).

Yep, thanks for the tips. It turned out to the the stock, inline fuse.

Popped it in, and the transmission is working properly when it should, and when I tell it to, it only shifts into 1st/2nd.

Just the way I wanted it! And my lighted switch even works.