NV3550 Drama

[BigTLang]

Good morning all!

This morning on my way to school, I was going to downshift when my trans wouldn’t let me shift into any gear (not just being a little stubborn, not even a good bit of pressure would get it to go.)

Doing a little bit of looking around, checked for any leaks from any fluid and also checked the fluid. Noticed it’s a brownish-red color, and after doing some research, it says that old fluid can absorb moisture and raise the level, which the level was up when I checked. Could it just be a fluid flush, or do yall think I’m in for a throw out bearing replacement? Thought I’d get an opinion from more knowledgeable people than me before I did anything. Thanks!

 

[ColoJeep]

Sounds like your clutch isn't disengaging . With the engine off and transmission in 1 st. gear with the clutch pedal pushed in , can you start the engine and the Jeep stay still ?

 

[machoheadgames]

Can you shift it into any gear with the engine off?

 

[BigTLang]

Can you shift it into any gear with the engine off?

Yes.

 

[BigTLang]

Sounds like your clutch isn't disengaging . With the engine off and transmission in 1 st. gear with the clutch pedal pushed in , can you start the engine and the Jeep stay still ?

When I was on the road, I tried doing that and it was creeping when it lit off and bogging real bad. When we got it back to the house, it worked like normal. It’s very weird haja

 

[machoheadgames]

Yes.

Sounds like a clutch release related issue then. Hopefully nothing more than a master/slave cylinder assembly. But it could also be a TOB falling apart or pressure plate gone bad.

 

[BigTLang]

Sounds like a clutch release related issue then. Hopefully nothing more than a master/slave cylinder assembly. But it could also be a TOB falling apart or pressure plate gone bad.

That’s what I’m hoping for as well. A fluid flush is easier than a transmission swap lol

 

[machoheadgames]

That’s what I’m hoping for as well. A fluid flush is easier than a transmission swap lol

A transmission fluid flush isn't going to do it, you are probably going to need to buy a hydraulic master/slave cylinder assembly. It's not the transmission if you can shift it fine when the engine is off.

 

[sab]

I agree with most of the posts so far, but are you sure you have an NV3550? Your profile states yours is a 1999, and I thought the NV3550 was first used early in production for the 2000 model year (the transition from AX15 to NV3550 took place during the 2000 production run).

That said, no matter what transmission you have, the first thing to investigate is whether the clutch slave piston is moving. I don't know if there's an inspection port or window on the AX15 or NV3550. If so, look in there while someone pushes the clutch and see if the rod/fork are moving. If you find that the fork is not moving, you would typically replace the clutch hydraulics as a unit (reservoir, master cylinder, hose, and slave cylinder). I say typically because that's how Jeep intended it. You can find the cylinders separately in the aftermarket, though I've never figured out how you connect them because the hoses don't seem to be available separately.

If the slave piston is moving, then you'll have to pull the transmission to take a look at the clutch fork, release bearing and pressure plate to see if the problem is there. Good luck, and if you decide to tackle this yourself, this forum will be very supportive and help you through the process, I'm sure.

 

[BigTLang]

I agree with most of the posts so far, but are you sure you have an NV3550? Your profile states yours is a 1999, and I thought the NV3550 was first used early in production for the 2000 model year (the transition from AX15 to NV3550 took place during the 2000 production run).

That said, no matter what transmission you have, the first thing to investigate is whether the clutch slave piston is moving. I don't know if there's an inspection port or window on the AX15 or NV3550. If so, look in there while someone pushes the clutch and see if the rod/fork are moving. If you find that the fork is not moving, you would typically replace the clutch hydraulics as a unit (reservoir, master cylinder, hose, and slave cylinder). I say typically because that's how Jeep intended it. You can find the cylinders separately in the aftermarket, though I've never figured out how you connect them because the hoses don't seem to be available separately.

If the slave piston is moving, then you'll have to pull the transmission to take a look at the clutch fork, release bearing and pressure plate to see if the problem is there. Good luck, and if you decide to tackle this yourself, this forum will be very supportive and help you through the process, I'm sure.

Funny enough, this Jeep has been in my dad’s friend circle since one of his buddies bought it from the original owner. I was told that he replaced the trans with an NV3550 at one point, and it has a short first gear.

I appreciate the advice, thank you!

 

[GoldenGorilla]

Assuming it has the NV3550's bell housing. It's bolt pattern is the same as the earlier AX-15 and there are reasons you would keep the earlier bell housing if you had it.

I had my NV3550 out of my '04 recently and took a photo after I cleaned the gunk out of it from a throwout bearing that puked it's grease and the factory standard leaking RMS. There is no inspection port per se. IMO best inspection option would be to pull the starter and peak through there. The other option is the crank position sensor up at 10:00, but I'd generally not touch that unless you need to as they occasionally get fussy if moved and cause check engine light drama.

 

[BigTLang]

Update: I ordered a slave+master cylinder this afternoon. Comes tomorrow but I’m not sure when I can install it, I will update when it’s in!

 

[BigTLang]

Update: slave and master cylinders are installed!

Pros: clutch feels better than before and shifts are smoother.

Cons: after the test drive, I noticed a noise coming from the transmission when I shifted. Listened closer and Everytime I shift into another gear and let out the clutch, it makes this screeching sound. I think I might be in for a TOB replacement.

 

[GoldenGorilla]

Update: slave and master cylinders are installed!

Pros: clutch feels better than before and shifts are smoother.

Cons: after the test drive, I noticed a noise coming from the transmission when I shifted. Listened closer and Everytime I shift into another gear and let out the clutch, it makes this screeching sound. I think I might be in for a TOB replacement.

Yeah, that was my throwout bearing for a long time. Unless you know the clutch has been replaced recently, you might want to do it while there. The LUK clutch parts aren't too expensive and the work to drop the transmission to get there is.