2000TJ NV3550 not synch'd

Thanks Bill,

I'll ask about the sunc rings when I take it back. I really appreciate the reply. I didn't want to go through the hassle if all I had to do was adjust the clutch linkage or something so simple. I'll look at the parts list from the previous repair and see if it gives enough info to tell what was replaced.

This sounds like he put the wrong oil in the trans. DC recommends a no-sulphur GL3 oil for the NV3550, which is rather expensive but can be sourced through the dealer. Sulphur in gear oils is great for the gears & bearings, but causes the synchros to slip excessively, resulting in the grind you describe. My bet is he put GL5 lube in it. If that's the case, before you do anythin have it drained and refilled with the proper fluid.

The proper fluid can be found at the dealer or your local auto-parts store as Pennzoil Syncromesh manual transmission fluid.

essentially

synchronized.

Thanks Jerry (and Matt, in thread)

Parts List from the previous work shows FP-Number 4874464, Lubricant

It looks like the right fluid. My Owners Manual says: "For 4.0L models with a manual transmission - use only Mopar Gear Lubricant: Part # 4874464. This is the only fluid recommend for this transmission." The quote includes their typo for "recommended" - you would think someone at Chrysler would check their manuals for typos.

The parts list does show five sync rings. FP Numbers: 4874363, 4874405,

Group, Thanks for the help.

Masnor

essentially

synchronized.

That's the right stuff. With that confirmed I'd be sure the clutch is disengaging completely. I might also suspect a dragging pilot bearing.

Bill,

Good call on the sync rings. I called today and was told that two of the rings just replaced the first week of September (2004) were causing the shifting problems. I hope to get the TJ tomorrow evening. I'll never go to that Chrysler service location again.

I also hope they don't overfill the transmission this time. I was still smelling fluid smoking off of the exhaust pipe and muffler when I took it back last week. And I had degreased and washed the entire under carriage.

Five star service, they say.

Long story on the PowerTrax (another thread, same TJ) and this thread is essentially at an end.

The Jeep Dealer rebuilt the transmission a third time and the sync problem was as bad or worse than ever. The Chrylser shop and the shop that put in the PowerTrax thought that removing the PowerTrax might indicate the source of the problem, or what wasn't the problem. So, the PowerTrax is out (back to stock Dana 35) and the sync problem symptoms are drastically reduced, but still present. None of us can figure out why, but the PowerTrax will have to stay out and I am probably going to live with the remaining sync symptoms. There is now only a mild crunch when shifting into second and a barely noticable mis-sync in third. It's still annoying, but it's not worth the pain of going back to the dealer (30 miles - warranty) and the lack of the Jeep for about three weeks (cumulative).

After the bad memories of this misadventure fade I'll try to find an alternative to the PowerTrax. It had taken most of the fun out of commuting anyway.

The throwout bearing has been replaced, as have all of the sync rings, some more than once. Removing drive shafts has generally shown that the rear diff was aggravating the symptoms, but removing the rear driveshaft did not eliminate the symptoms - just as removing the PowerTrax has not eliminated the problems.

Thanks for all of the suggestions for both the PowerTrax and the sync problems.

Are you sure they put the right oil in this trans? The AX5s, AX15s and NV3550s all take special GL3 (no sulphur) lubes to prevent the synchros from clashing, particularly when cold.

drastically

Which is why I'm asking. After the second repair failed it's obvious they're not fixing the real problem.

What he's complaining about isn't a common fault with these gearboxes, but "adding the wrong oil" is, and when high-sulphur oil is installed in any of these boxes the issue he has with gear clash is exactly the symptom.

I just double clutch. No clash...