Gimme back my shifter and other random questions

[02SteelBlue]

02 X 4.0

When shifting, up or down, my shifter gets "stuck" for a second. I let it go then try again and it works. This isn't occasional, nor only when hot or cold. It's not so bad I can't drive it, just annoying.

I'm a professional internet mechanic, and it seems it may be related to synchros. Does that sound right, and if so can they be replaced individually?

Second, is idle RPMs. I've cleaned the IAC and throttle body, but RPMs stay around 1k at idle. This may be normal, but just looking for others input. I know I can replace the IAC, but is 1k at idle bad?

Lastly, is the occasional sluggish start. I wasn't sure where to start until yesterday when it was sluggish and the gas guage was pegged at empty, even though it had 1/4 tank. It sounds like the fuel pump check valve. If this thinking is correct, is that something that can be performed by a professional internet mechanic, or is that better left to the real pros?

Thanks in advance for reading and offering your time/ experience!

 

[ac_]

I am not sure what you mean by shifter gets stuck. Usually if synchro's start to go bad it starts to grind going into gears. How it works is when you hit your clutch to shift it disengages power past the flywheel. Meaning no more engine power through the trans, but you still get movement in the gears from left over inertia. So the synchro's stop the gear totally for you to shift. Sometimes in down shifting if you have really low gears, you could get into a gear bind situation. I mostly see that shifting in first or reverse from neutral, if the gears are moving, usually they will jiggle in without any kind of a bind.

If you are truly getting a bind while you are driving where your shifter is not grinding but stuck in gear and wont come out? I might think two things. One, worn out gears, or two, detent springs bad. I rarely see that though. Without driving it it is hard to tell you what the actual issue is. but for the most part bad synchro's will give you more of a grind while you shift condition.


You next issue your idle should not be at 1K, You might have a vacuum leak as well as your IAC could actually be your vacuum leak. I sort of have the same issue, but mine idles at 750, but it doesn't go down to that till my wheels have stopped moving, so say I am coming to a stop, but haven't quite stopped yet, mine hangs out at 1k, but then when the TJ actually stops it drops down to 750. Of which I think that is slightly high too, I need to look at the spec. I have cleaned my IAC also, but it seems like it changes for about a day then goes right back to the same thing, so I am not positive if that is normal or not, but I have had too many other fish to fry lately to work on that myself. But to answer your question 1K idle is not normal.

As far as your sluggish start, too many things it could be, but say if you have a vacuum leak causing your idle problem, that might be your sluggish start issue too. My vote is to fix that first and see where you are.

Good luck and keep us posted.

 

[02SteelBlue]

I am not sure what you mean by shifter gets stuck. Usually if synchro's start to go bad it starts to grind going into gears. How it works is when you hit your clutch to shift it disengages power past the flywheel. Meaning no more engine power through the trans, but you still get movement in the gears from left over inertia. So the synchro's stop the gear totally for you to shift. Sometimes in down shifting if you have really low gears, you could get into a gear bind situation. I mostly see that shifting in first or reverse from neutral, if the gears are moving, usually they will jiggle in without any kind of a bind.

If you are truly getting a bind while you are driving where your shifter is not grinding but stuck in gear and wont come out? I might think two things. One, worn out gears, or two, detent springs bad. I rarely see that though. Without driving it it is hard to tell you what the actual issue is. but for the most part bad synchro's will give you more of a grind while you shift condition.


You next issue your idle should not be at 1K, You might have a vacuum leak as well as your IAC could actually be your vacuum leak. I sort of have the same issue, but mine idles at 750, but it doesn't go down to that till my wheels have stopped moving, so say I am coming to a stop, but haven't quite stopped yet, mine hangs out at 1k, but then when the TJ actually stops it drops down to 750. Of which I think that is slightly high too, I need to look at the spec. I have cleaned my IAC also, but it seems like it changes for about a day then goes right back to the same thing, so I am not positive if that is normal or not, but I have had too many other fish to fry lately to work on that myself. But to answer your question 1K idle is not normal.

As far as your sluggish start, too many things it could be, but say if you have a vacuum leak causing your idle problem, that might be your sluggish start issue too. My vote is to fix that first and see where you are.

Good luck and keep us posted.

Appreciate the reply!

I haven't heard any grinding, so maybe not the synchros. I press the clutch, go to shift (let's say 2nd to 3rd), and the shifter doesnt go up so I can move it into 3rd. I just let the shifter go, then try again (with the clutch in the whole time) and it works. Like I said, mostly just annoying.

As for vacuum leaks, I'll have to read more about checking that, as my internet mechanic skills haven't reached that far yet!

 

[AndyG]

I’d remove that shifter boot and inspect everything.

I saw a dum dum sucker disable a Tundra once

 

[Rich1961]

My previous TJ with the NV3550 had the same problem, hard to shift out of gear. Had to do exactly what you are doing to shift. At the time I assumed it had the factory fluid in the transmission (about 60k on the Jeep). I talked to a couple of transmission guys I knew and they had no answer for me. I was researching getting a new transmission when I decided to try Amsoil Synchromesh. I ran it for about 500 miles and no improvement. Out came the Amsoil and in went the factory fill lube, Pennzoil Synchromesh. Same results, no improvement. Frustrated, I thought what the hell, I'll try Redline MTL as a last resort, as I'd heard a lot of good reports about it, Jerry being one of them. Drained the Pennzoil and filled with the Redline. Wow, noticed a big improvement on the first drive, and it got better over the next 100 miles. From there on out it shifted great until I sold it about 20,000 miles later.

Now I will say that I am an Amsoil user on some things and like their product. But in this case the Redline eliminated the problem. I can't explain it, it just worked for my transmission.

Rich

 

[02SteelBlue]

My previous TJ with the NV3550 had the same problem, hard to shift out of gear. Had to do exactly what you are doing to shift. At the time I assumed it had the factory fluid in the transmission (about 60k on the Jeep). I talked to a couple of transmission guys I knew and they had no answer for me. I was researching getting a new transmission when I decided to try Amsoil Synchromesh. I ran it for about 500 miles and no improvement. Out came the Amsoil and in went the factory fill lube, Pennzoil Synchromesh. Same results, no improvement. Frustrated, I thought what the hell, I'll try Redline MTL as a last resort, as I'd heard a lot of good reports about it, Jerry being one of them. Drained the Pennzoil and filled with the Redline. Wow, noticed a big improvement on the first drive, and it got better over the next 100 miles. From there on out it shifted great until I sold it about 20,000 miles later.

Now I will say that I am an Amsoil user on some things and like their product. But in this case the Redline eliminated the problem. I can't explain it, it just worked for my transmission.

Rich

Ya, I read all about the Redline MTL when I got the Jeep in January. I replaced whatever was in there with MTL, but no change.

I can do a second drain/ fill with it if its believed that'll help.

 

[Rich1961]

Ya, I read all about the Redline MTL when I got the Jeep in January. I replaced whatever was in there with MTL, but no change.

I can do a second drain/ fill with it if its believed that'll help.

One thing I just remembered, at the time reading of similar issues on other forums, when I drained the Amsoil I filled the transmission with Kerosene, placed the transfer case in neutral, started the Jeep and at an idle ran the transmission through all the gears for about 30 seconds and shut it down. Drained the Kerosene and let it drip for an hour and then ran the Pennzoil before changing to the Redline.

 

[02SteelBlue]

One thing I just remembered, at the time reading of similar issues on other forums, when I drained the Amsoil I filled the transmission with Kerosene, placed the transfer case in neutral, started the Jeep and at an idle ran the transmission through all the gears for about 30 seconds and shut it down. Drained the Kerosene and let it drip for an hour and then ran the Pennzoil before changing to the Redline.

Kerosene...interesting! Sounds like a project for next weekend, thanks.

 

[Adam Johnson]

My previous TJ with the NV3550 had the same problem, hard to shift out of gear. Had to do exactly what you are doing to shift. At the time I assumed it had the factory fluid in the transmission (about 60k on the Jeep). I talked to a couple of transmission guys I knew and they had no answer for me. I was researching getting a new transmission when I decided to try Amsoil Synchromesh. I ran it for about 500 miles and no improvement. Out came the Amsoil and in went the factory fill lube, Pennzoil Synchromesh. Same results, no improvement. Frustrated, I thought what the hell, I'll try Redline MTL as a last resort, as I'd heard a lot of good reports about it, Jerry being one of them. Drained the Pennzoil and filled with the Redline. Wow, noticed a big improvement on the first drive, and it got better over the next 100 miles. From there on out it shifted great until I sold it about 20,000 miles later.

Now I will say that I am an Amsoil user on some things and like their product. But in this case the Redline eliminated the problem. I can't explain it, it just worked for my transmission.

Rich

I had a similar problem with the NV3550. Mine wouldn't go into either of the far right positions (5th or Reverse) when it was cold out. A change of fluid made it all work as it should again.

 

[02SteelBlue]

Finally got around to changing the fluid again. When I bought the Jeep in January, I replaced whatever was in there with MTL.

Still having problems with the shifter not coming out of gear easily, I changed the fluid to Mopar's fluid. Also changed the front and rear diff oil as well. Fifty or so miles later and no change.

This doesnt always happen, but when it does, it is only when the transmission is warmed up (contrary to my earlier post).

Can a bad O2 sensor cause symptoms like this?

 

[Goatman]

Are you ham fisting the shifter? Try as if you are grabbing an egg instead of the knob. Do you feel any clunky or clicks when doing this? Sounds like the shift forks are not engaging the the shifter correctly.

 

[02SteelBlue]

Are you ham fisting the shifter? Try as if you are grabbing an egg instead of the knob. Do you feel any clunky or clicks when doing this? Sounds like the shift forks are not engaging the the shifter correctly.

I dont know what ham fisting is, but it doesnt sound good.

It can be clunky going into gear sometimes, most notably second and third. I've read previously that the NV3550 can be clunky, and that's normal for it. For what it's worth, there are no grinding sounds (or any sounds for that matter) when shifting.

I'm pretty new to working on a vehicle, but definitely willing to try. Are the forks something that I can check, or is that mechanic territory?

I appreciate you taking the time!

 

[Goatman]

From what I have read this tranny is made/designed by Mercedes. Those Germans are known for their ability to over engineer almost anything. There are a lot of transmission shops that dont want to mess with this one. The shifter rails/slider forks look like an erector set competition to use the most pieces. A lot of people advise installing an AX-15 when the 3550 coughs its last breath. While I really enjoy the deep 1st gear and the tall 6th gear, service and even parts are going to be hard to find. If you are lucky enough to have a GOOD shop near you, stop in and talk to the mechanics about what you have going on. Bring a pizza or a 12 pack of soda and they should be willing to send you home whith a good idea for what is best for your Jeep.

 

[pagrey]

How is your clutch? It can cause the transmission to stick in gear. If you are stopped and push in the clutch, pause and then put it gently into reverse does it grind? Also I hate to say, a lazy foot on the clutch pedal or a floor mat blocking the pedal can cause this.

 

[02SteelBlue]

How is your clutch? It can cause the transmission to stick in gear. If you are stopped and push in the clutch, pause and then put it gently into reverse does it grind? Also I hate to say, a lazy foot on the clutch pedal or a floor mat blocking the pedal can cause this.

I've had a few manuals, but never had to replace clutches. Consequently, I dont know what a bad clutch feels like. I've read a good bit about it, just hasn't happened to me yet.

That said, one thing I read was, while in gear, hold the clutch in and apply some throttle. If the Jeep starts going forward, it may indicate a clutch problem. I did that and didnt move forward. Not the end all be all of tests, I know.

I'll try the reverse idea this evening after work and report back. As for the lazy foot, I'm guessing you mean the clutch not fully depressed? I like to think I do, but I'll be keeping a closer eye on my driving habits as well.

I still have the original carpet and mat. They're pretty thin, so I dont think they are the cause.

Appreciate the help, and I'll follow up soon.

 

[pagrey]

Clutch fluid level too?

 

[xxdabroxx]

Mine seems to have an issue from time to time with the spring or whatever returns the shifter to center. Not sure what it is but it gets slightly bound up and I jiggle it and it frees up just fine. I haven't taken the boots off to see why yet though.

 

[pagrey]

Mine seems to have an issue from time to time with the spring or whatever returns the shifter to center. Not sure what it is but it gets slightly bound up and I jiggle it and it frees up just fine. I haven't taken the boots off to see why yet though.

A buddy of mine found a few dollars in change wedged in his somehow under the boot but it was more trouble getting into gear than out.

 

[02SteelBlue]

I've taken off the shift boot and the outer boot. Looked pretty clean on mine. Theres a little inner boot under that - the change was in there?

 

[pagrey]

I've taken off the shift boot and the outer boot. Looked pretty clean on mine. Theres a little inner boot under that - the change was in there?

I never saw it, just heard the story, I'll have to ask.