stinsonbr

Hey all, I have a 2000 xj, 4.0 with 230k miles and the aw4. I've been losing my overdrive every so often while on the freeway, pretty randomly it seems. Then just this morning the Jeep wouldn't turn over. After reading real quick on some people with similar issues i wiggled the shifter and it started fine. I replaced the neutral safety switch a year and a half ago, and am getting a feeling that it's to blame for both these issues. Could it have been slightly knocked out of alignment? I thought I was careful when aligning it when I installed it, and it seems weird that I'm getting these problems over a year after. Any advice would be appreciated.

Brandon

MonacaYankee

The NSS won't cause any problems with overdrive. I recommend adjusting your kickdown cable first. (Search google adjust jeep cherokee kickdown cable). If that does not work it's probably your solenoid s in the trans.

Radi

Later XJ's (96 or 97 and newer, IIRC) the NSS can mess with overdrive or TCC lockup, the brake pedal switch can cause troubles too.

Are you bumping out of overdrive, or is the TCC unlocking? TCC unlock is about 300 RPM difference.
You can check the TCC by gently tapping the brake while cruising over 45 mph. RPM's should jump up about 300, then go right back down.

stinsonbr

TCC is locking just fine. What happens is the exact same as being in 3rd, and it shifts a bit rougher.

MonacaYankee

I didn't know that. How does the NSS control od and tc lockup?

Radi

Earlier XJ's the NSS was only used for backup lights and starter interlock, controlling the start relay (in the PDC) directly. The Transmission and PCM didn't know it existed.
Somewhere around '96 they plugged the NSS into the PCM and expanded it's functions to include a role in lockup and shift decisions. If you bypass it in a 96+ you'll get a CEL about the 'range selector' and may find the transmission acting funny.

Radi

Agreed with checking the TV cable as mentioned earlier. Fluid clean and at the proper level?

Roler

I'd check fluid for level and quality first.
What brand NSS did you put in there? My aftermarketcheap $46 one still is going after 1.5 yrs, but I expect no heroics from it.

PUNISHER

Roler, you answered my "no downshift" post this week. So just to make sure, the NSS has nothing to do with not downshifting? I just replaced the NSS in my 97 and didn't take the XJ for a very long test ride afterwards. Past Sunday was the longest drive I have made since changing it and I started having this issue. Just want to double check before I start checking what you and others suggested. Thanks again

stinsonbr

I don't remember what brand, but it wasn't a cheap one. Got it new for like $200. Fluid is not super clean, but full. There are shavings in the fluid, so over the summer I changed only as much as the pan holds twice (with ~100 miles of driving in between the changes), and no flushing. I'll adjust the TV cable today and see what happens.

Radi

Nope. It has no idea what you are doing with the throttle. That information comes from the TPS and the TV cable.

KD4315

The NSS has nothing to do with your problem. I would check for codes just in case to see if any are stored. Nect I would make sure the fluid is nice and pink and isn't dirty or smells burnt. My gut says you have a bad shift solenoid. Even though one of them may be bad I would change them all. You can buy a set of eBay for about $100.

PUNISHER

Thanks guys! I will get the XJ in the garage this weekend and see what I come up with.

My apologies to stinsonbr for jacking his thread!

Roler

THe NSS is not involved in shifting characteristics, its used to ' complete' the circle in order to be able to start the enigine. If its (completely) faulty, it wont even crank, much like a dead battery. Typically it will give intermittent symptoms before it fails completely.

blue_00xj

I actually had issues shifting, my 00 xj wouldn't shift into fourth gear. I took my nss out cleaned out the old dielectric grease, cleaned the copper connections with emery cloth. Put everything back together, cel went away and I was able to shift into fourth. Its been three or four months since cleaned and works like brand new.