Hard shifting NV3550 after warming up

[CO-OffRoad-TJ]

My '03 TJ Sport 4.0, 5speed manual with 127k miles. I just purchased it and had it gone through before setting it up to be a toad behind my motorhome. I had all the fluids changed, some seals replace, and a B&M transfer case shifter cable conversion kit installed. All worked great when it came back from the shop.

Now, a few hundred miles later, I'm having shifting problems. The transmission shifts fine when cold (just starting out for the first time in the day) or when the engine is off. While driving awhile, shifting is easy and smooth at highway speeds but when I slow down below 10 mph or if I'm stopped, it shifts hard or may not want to go into any gears - no grinding, it just refuses to move into geaar. I can usually force it into gear, and if I turn off engine, it goes into any gear easily.

There is some mild bearing noise when clutch is let out (in neutral).

Same problem with transfer case, i.e. if the transmission shifter is hard, the transfer case going from 2-wd to 4 high or neutral is hard, but if the engine is off, it shifts fine.

After all this, once moving again at speeds > 5 or 10 mph, clutch works and feels fine and transmission shifts smooth. Never any grinding going into any gears.

 

[Chris]

As much as I hate to say this, sometimes it's better to not change the transmission on really old, higher mileage transmissions (especially the steaming pile of crap that is the NV3550).

I went through something very similar with my Ford F150 transmission recently. No problems at all before the fluid change but after the change it's been nothing but problems.

I guess the first thing I would ask is what fluid and what weight fluid did you put in there? Have you made certain that the transmission is full? It could be low. That's where I would start.

 

[CO-OffRoad-TJ]

As much as I hate to say this, sometimes it's better to not change the transmission on really old, higher mileage transmissions (especially the steaming pile of crap that is the NV3550).

I went through something very similar with my Ford F150 transmission recently. No problems at all before the fluid change but after the change it's been nothing but problems.

I guess the first thing I would ask is what fluid and what weight fluid did you put in there? Have you made certain that the transmission is full? It could be low. That's where I would start.

I hope it's that simple. Thanks, I'll check.

 

[Chris]

I hope it's that simple. Thanks, I'll check.

I hope so too!

 

[GoldenGorilla]

That sounds to me that the clutch slave cylinder or fork isn't depressing the clutch pressure plate all the way. That there is some torque being applied when the clutch is depressed. That bolts on to the belt housing on the driver side and is worth visually inspecting.

I have the NV3550 and changed the fluid to the Redline recommended here for it. I'm the only owner and it only had 70k on it at the time. I haven't been totally happy with the synchro behavior since. It's not grinding, but it's not as smooth as it used to be.

 

[CO-OffRoad-TJ]

That sounds to me that the clutch slave cylinder or fork isn't depressing the clutch pressure plate all the way. That there is some torque being applied when the clutch is depressed. That bolts on to the belt housing on the driver side and is worth visually inspecting.

I have the NV3550 and changed the fluid to the Redline recommended here for it. I'm the only owner and it only had 70k on it at the time. I haven't been totally happy with the synchro behavior since. It's not grinding, but it's not as smooth as it used to be.

I checked the bolts holding the slave cylinder and they are tight. Really strange that it works fine first thing in the morning (cold) but almost impossible to shift after running awhile and the jeep is stationary. Shifts fine going down the road.

 

[GoldenGorilla]

I checked the bolts holding the slave cylinder and they are tight. Really strange that it works fine first thing in the morning (cold) but almost impossible to shift after running awhile and the jeep is stationary. Shifts fine going down the road.

That does curiously sound like a clutch hydraulics issue. Either an issue with the slave needing to be bled, or the assembly replaced. It sounds like there is air in that and it is expanding and causing issues as it warms up.