NV3550 shifting issue after Detroit TrueTrac and re-gear


New Member
Original poster
Nov 11, 2021
Fort Collins, CO
Hi All,

Long time searcher, lurker, fan of Jerry... First time poster.

After reading just about every Nv3550 post on this forum (there's a LOT... and all very helpful) I'm facing a weird issue. I have a 2001 TJ and have rigorously maintained the NV3550 with Redline MTL over it's lifetime. I've literally never had an issue with it. It has shifted smoothly since putting in RedLine MTL a LONG time ago and changing every 15k thinking it would last and my wallet would drain slowly. Jeep now has about 140k on it and I recently upgraded the Dana 44 with a Detroit TrueTrac and 4.56 G2 gears after going to 33's. This was all professionally done and has a 3 year warranty on the work.

The day I took it for gears, 0 issues. No shifting problems whatsoever. The day I took it home a few days later, I get issues that feel like synchro problems in upshifts only in the common NV3550 pattern... aka 1-2 and 2-3. Downshifts have literally 0 problems and feel just like they did pre-locker/gear install. For years I ran with 3.73's and 32 inch tires with the factory TrashLok in the back and no issues.

I would be tempted to say synchros but honestly, they were perfect and that's not something that fails in 1 day. I've had a previous vehicle with synchro issues and it's jsut a little different.

Possibly NP231J chain issue? NV3550 hates locker? Throwout bearing? Pilot bearing? I have no idea, but would rather not throw parts at it as it literally was related to a gear install. Clutch is original, master/slave are LUK and brand new (beginning of the parts buying waste)....

Any ideas would be absolutely welcome. Some sort of test would be great, just not sure what to do.

Confused and frustrated in CO.
Realized yesterday the terrible noise that coasting in gear with the clutch in made the throwout bearing make. So when the rear wheels make the shaft turn in neutral it sounds straight awful. Going to do the clutch and see where I end up.
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Nothing behind the transmission can effect shifting but it sounds like you are onto your problem. If the throwout bearing is bad it will make the same noise moving or parked. If the Jeep has to be moving for the noise to happen it is possible there's something else going on with the transmission.
Wanted to update for others facing the same problem. It's fixed.

Pulled the transmission to find one of the clips on the throw out bearing snapped and the bearing was pretty trashed. Found a few shavings in the bell-housing as well. Clutch looked great for 140k and the flywheel was in excellent shape.

Did a LUK standard clutch, pressure plate, pilot bearing, etc. and it resolved 95 % of my issues. I did use an all metal throw out bearing... I'm sure the LUK one is 'fine' but damn it feels cheap. I was more comfortable with one that resembled OEM.

I'm assuming with tension on only one side, it was probably binding up a bit on the sleeve and causing shifting issues.

Relieved and exhausted... hate those E12 bolts on the top...