I have a 2001 XJ with a 3.5" Rubicon Express Super Ride. Recently, it has been stalling or locking up when it goes over hard bumps. It doesn't feel like the engine cuts out. It feels like the problem is in the drive train. I replaced the TPS sensor, just in case, but that didn't fix problem. I'm not sure what to do at this point. There has been an increasing vibration in the drive shaft somewhere. The front drive shaft does twist more than I'd like, but the rear is solid. All the U joints feel fine too. I'm lowering the transfer case as soon as the kit gets here, to try and correct the vibration. I'm really at a loss with the stall over bumps though. Any help would be appreciated.

 

Manual or auto?

 

Auto

 

Time to noggin poke and see what's loose. But need to be specific. Do your gauges go to zero or by locking up do you feel something different. And chances are, a TC drop isn't solving anything. Its a BandAid. An SYE is the fix for the vibrations from the lift. As for the front shaft. Are you getting rotational movements or up and down. Specifics will help solve issus

 

The gauges don't go to zero. The tach does show a slight drop. As for the TC drop, I don't think it will correct at this point either. I figured I would start with inexpensive corrections first, and go from there. The front shaft is just rotational. If I had to guess, it's a quarter inch or so. Everything else has I've poked on seems to be fine. I do have some loose O2 sensors, but I wasn't sure if that could cause a stall. Again, it just doesn't feel engine related, but I'm no expert. There is also no check engine light.

 

I agree on the TC drop kit you need an SYE really and with LPD30 a lift can cause issues with them, a good place to start.

 

Could the lack of the SYE be causing the sudden jerk?

 

Also, would it need to be a heavy duty spline replacement, or would something like http://www.ironrockoffroad.com/10482.html be sufficient?

 

Nothing in the driveline can stall the engine unless the torque converter clutch is energizing so start looking for a loose connection somewhere. The O2 shouldn't cause a stall, but if it's loose fix it.

A 3.5" lift shouldn't require a SYE. If the u-joints are worn a lift will exaggerate their effect. A TC drop should alleviate things assuming the u-joints are good and the angles are good when it's done. Ideally, the angles of the front and rear joints are the same so that they cancel each other.

 

The later models require an sye much earlier than the early years.

 

Now you know this isn't a proper statement to make. My 01 had a 3" lift. New u joint with a TC drop didn't stop the decelerating/accelerating grinding noise. An SYE did. Every jeep is different.

OP, did you say yet if you tried removing the front driveshaft and driving around. Make sure nothing is binding up on you

 

I haven't tried removing the drive shaft yet, so that's probably my next step. I can try removing one at a time to see if one or the other is causing the problem. Any foreseeable problems with running down the road in 4 hi without a rear shaft?

Thanks for the help guys.

 

Turning on throttle will be a ***** but that's about all.

 

Yup pretty much this but with an 01 there's no risk of fluid leak OP. So have at it. I suggest front shaft first. An old worn out DC joint can lock up if the ball or spring is screwed up

 

OK thanks guys. It might be next weekend before I can get to it. I'll check back in when I know more. I really appreciate the help. I'm learning as I go.