Lugging Into First Gear

[tenortech]

I've got a lug when I take off into first gear or run in reverse, especially worse when I'm on an incline. My 2004 is a 5 speed manual transmission with the NV3550 and 88k miles. After researching I'm learning it could be the clutch or something related to the clutch. But I'm also learning that the OEM clutch that was used should last 200k miles plus even with abuse.. So what can I do to rule or rule out the clutch?

The gears also grind between first and second and third when everything is cold.. Fluids were changed about 5k miles ago and are not low.

Not sure if this matters, but I have a leak between the engine and transmission that has gotten progressively worse over the last couple of weeks. It will leave about a 2” circle on the ground over 8 hours. I thought it might’ve been the rear main seal, but maybe it’s something else?

I'm new to working on Jeeps, but can follow a good YouTube video.

 

[JKP]

35s and what gearing?

 

[tenortech]

35s and what gearing?

4.88 I've had this Jeep for about 10k miles and it just started about 500 miles ago.

 

[JKP]

Mine have the AX-15 and NSG-370, so no experience with the NV3550, but as the syncros wear, the shifting gets worse, especially in the cold. A synthetic fluid might help.

I got over 200k on both OEM clutches, and it was the pilot bearing that went out both times.

If the engine is bogging off idle, I'd suspect the IAC sticking, or maybe TPS.

 

[tenortech]

Mine have the AX-15 and NSG-370, so no experience with the NV3550, but as the syncros wear, the shifting gets worse, especially in the cold. A synthetic fluid might help.

I got over 200k on both OEM clutches, and it was the pilot bearing that went out both times.

If the engine is bogging off idle, I'd suspect the IAC sticking, or maybe TPS.

I've replaced both of those sensors and I did put a synthetic fluid when I changed it about 5k miles ago. Shifting isn't too bad, but if I rev it up over 2k RPMs it does get a little crunchy if I shift fast between 1, 2 and 3 gears.

 

[macleanflood]

Have you checked your fuel pressure or monitored live ODB data and checked your fuel trims?

-Mac

 

[tenortech]

I checked fuel pressure a couple months ago on off, idle, and throttled and it was within specs. I had a rough idle issue and thought this might be the issue.

 

[ItchyDong]

Clean your IAC passage. Replacing the valve doesn’t fix a gummed up bypass channel.

My clutch was toast at 92k when I bought it. But it would rattle and buck like a horny bronco unless I revved and slipped the shit out of her. I doubt your clutch is the cause.

 

[tenortech]

Clean your IAC passage. Replacing the valve doesn’t fix a gummed up bypass channel.

My clutch was toast at 92k when I bought it. But it would rattle and buck like a horny bronco unless I revved and slipped the shit out of her. I doubt your clutch is the cause.

I made sure to clean that out too when I replaced it. I also had to make a new gasket for it since the old one crumbled away. It wasn't incredibly dirty though.

 

[tenortech]

Digging deeper and thinking maybe it's the slave cylinder and just hoping it's not my clutch? Pedal engages about halfway down and doesn't really feel spongy, but the pedal does go all the way to the floor. If I move up and down from floor to halfway nothing grinds or anything. I don't see any leaks around the master or slave, but this is what the fluid looks like.. does it just need a flush?

 

[ItchyDong]

I made sure to clean that out too when I replaced it. I also had to make a new gasket for it since the old one crumbled away. It wasn't incredibly dirty though.

You cleaned it with the engine running?

 

[tenortech]

You cleaned it with the engine running?

No, was I supposed to?

 

[MikeE024]

I've got a lug when I take off into first gear or run in reverse, especially worse when I'm on an incline.

Any vacuum leaks?

Can the PCM cause this problem @Wranglerfix ?

 

[ItchyDong]

Yeah. Run the engine, spray carb cleaner directly into the throttle body. It’ll kill the engine. That’s good. When it’s dying, the pcm commands the IAC completely open in an attempt to save it, and in turn, forces the cleaner through the passage. Start it back up and do it over and over until the can is gone.

 

[tenortech]

Any vacuum leaks?

Can the PCM cause this problem @Wranglerfix ?

Definitely have a vacuum leak but it is in the HVAC controls. That's on my list to fix.
But would that cause my lugging when starting in first? If I don't start rolling quick enough I get a loud popping and can feel the Jeep catch with the pops.

 

[ItchyDong]

Definitely have a vacuum leak but it is in the HVAC controls. That's on my list to fix.
But would that cause my lugging when starting in first? If I don't start rolling quick enough I get a loud popping and can feel the Jeep catch with the pops.

Highly doubt that’s an IAC

 

[MikeE024]

Definitely have a vacuum leak but it is in the HVAC controls. That's on my list to fix.
But would that cause my lugging when starting in first?

Fix it and let us know. I had this exact problem due to a vacuum leak, but it was on a different platform.

You know you have the leak, so it makes sense to fix it and see what the results are rather potentially spin your wheels if you don’t need to. If it doesn’t fix it, you keep troubleshooting