07 JKU. I have been experiencing intermittent transmission slip (so I think?) for about the last 3k miles (I just rolled 100k). I have a 2.5" TF coil lift and run 35s. Typically when returning home and wanting to back into the garage (small incline) shifting from drive to reverse the JK 'bucks' sometimes a few times before it stays in gear and makes its way into the garage (about 30' in reverse). Today, however, I came home put it into reverse and got about 15' up the driveway and felt it buck accompanied by a loud clunk and grinding noise. Now the JK will not shift into drive or reverse. If its in neutral with the engine on, it will not budge. I have been attempting to push it into the garage by means of turning the engine off while in neutral. I checked the trans. fluid level @ nominal temp and its topped off; fluid is red is color with no smell. Looking under the JK with my wife in the drivers seat, the linkage moves @ the tranny in all positions. I had the transmission serviced; flushed/filled @ 90k.

I have been told the neutral safety switch causes all sorts of problems...but I'm wondering if its more than that. Im literally stuck...my only blessing is that it happened @ home and not somewhere else.

Any insight? I don't even want to guess at how much a repair is going to be as I have been quoted the NSS parts/labor is approx. $500.

 

My first thought was fluid level, but you covered that.
Second thought is ...Did you re-gear after installing the 35" tires?

 

yes. I re-geared less than 1k to 5.13.

UPDATE: with the JK in Neutral, engine on or off....the transmission seems to be 'binding'. I can no longer push the damn thing. While in reverse, the transmission sounds like a gear is just spinning.

 

Have you tried pushing it with the t-case in neutral?
With the bucking and clunking noise, I'm wondering if it may be the t-case.

Was the grinding noise more of a ratcheting noise?

 

I pondered the damn transfer case. To be honest...it could be one or the other..or both? How do I manually shift the transfer case into neutral? I suppose the noise could be described as ratcheting....

 

Ratcheting could be the parking pawl, if the shift linkage is out of adjustment.

Ratcheting could also be the splines in the t-case if that linkage is out of adjustment. Sometimes it's broken.

If the JK is on an incline, chock the tires.
Put the t-case into neutral with the t-case lever. Pull it from 2wd, through 4hi, into neutral.

 

Sorry..brain fart. Im back in business....sorta. With the t-case in neutral, I am able to push the damn thing again. With this being the case, what do you suspect the cause could be?

BTW...it was a mother F*kr to get it shift. I ought it with 76k on it...and now I am questioning if the case has ever been serviced?

 

The t-case will be hard to shift if there is a load on the drivetrain. If you were still on an incline, and it was not rolling on it's own, the driveline has some torque on it.

 

I had the JK at the foot of the drive way where its pretty level. It was stationary with the trans in neutral...still a PITA to shift the t case into all positions. Makes me lean more towards the t case. Definitely appreciate pointing out placing the t case into neutral.

 

Don't think of the t-case being hard to shift as a symptom of it being bad. When not in motion, the splines inside may not be lined up, making engagement difficult. Going into 4lo can be very difficult, even on a perfectly good t-case.