Pilot bushing question on a VG33

[Adam78]

This is actually about my 04 Frontier SC. Mods, if you feel like this should be posted elsewhere feel free to move it and my apologies but I could really use some thoughts on this.

I had my clutch replaced a year ago because it started making that groaning noise when you put the clutch pedal to the floor and I just assumed it was the T/O bearing. Well, it started doing it again a few months ago and it turns out that the pilot bushing should have been replaced as well. And this work was done at a dealer so I was not happy about that but I guess that's what I get for not educating myself.

So, they replace the pilot bushing recently and now getting the shift lever in first when you are at a dead stop is extremely stiff. If it is cold it is fine but it only takes about 10 minutes of driving for the issue to start presenting itself. I am wondering if they compressed the I.D. of the bushing when they installed it and obviously when it gets hot and the metal expands that one or two thousands of clearance gets taken away.

I know I am probably going to have to insist that they replace the bushing but before I do that I wanted to make sure that this isn't a normal break in scenario? Thanks in advance

[Zed Head]

That's a nice diagnosis of a problem.  Does it have the problem in all gears from a stop?  It should if it's the pilot bushing.  You're suggesting that the input shaft is binding in the pilot bushing and the shaft keeps trying to spin when it should stop.

I'd guess that it might wear/break in.  It looks like the Frontier uses a bushing and not a needle bearing like some do.  So it will either wear down to the perfect fit, or heat up and seize.  But, usually, holes get bigger as things heat up so it's odd that the problem gets worse with heat.  Maybe they didn't seat it far enough and as the shafts expand the input shaft is actually pushing on the bushing.  It might also be that it's not the bushing, maybe the clutch disc or pressure plate instead.  

Also, any chance they didn't get the clutch bled properly?  The bushing is in your mind but it could be something else.

I've never actually heard of that problem before, with a new bushing.  You'll probably get some clues in the next few weeks.  

[Adam78]

Thanks Zed Head.

Yeah, that's exactly what I am thinking. First gear is the most difficult to get into. In fact, it gets to a point that I can't physically force the gear shift into 1st but it will go into 2nd (although not without resistance). Now, I have noticed that as I am coming to a stop if I wait until the last second before I stop I can slip it into first. Of course that means that I am sitting at a red light with the clutch pedal depressed, which I don't like to do. I will also mention that if you cut the engine off you can row through the gears just fine. I don't think this is a transmission issue.

Regarding your point about the hole getting bigger with heat it seems like the fact that the bushing is press fit into a confined space (i.e., the tail of the crankshaft) would restrict the ability of the outside of the bushing to expand, thus only allowing it expand inward. Of course the crankshaft itself must expand somewhat but its expansion coefficient would be different because it is made of a different kind of metal. Well, that's getting into the weeds a bit. I'm with you in the sense that I think the master tech at the dealer wasn't careful with the press fit. Maybe it is like you suggest and not in all the way, maybe it is ever so slightly crooked, maybe when he seated the transmission to the engine the input shaft struck the bushing and scarred it. I've read that people suggest put the bushing in a freezer so that it will contract and slide in just a touch easier. 

I'll have the master cylinder hydraulic fluid changed but the fluid doesn't look black or anything. I haven't eliminated the possibility that the clutch could be dragging ever so slightly, but the fact that this is clearly a heat issue makes me lean toward the bushing being the culprit, but I could certainly be wrong. 

[Zed Head]

It's a fun puzzle but in the end, really, you paid for a service at a professional shop and they didn't get it right.  I'd take it back. let them test drive it, and let them fix it.  They have the tools and it should be a quick job.  If you wait too long they can claim something new happened.

[Adam78]

Yeah, you're right.

[Zed Head]

Be nice though.  The mechanic would have tested it while it was cold.  So he/she would not have known, it would have worked perfectly like you said.  Make sure it's nice and hot so they get full effect.

[Adam78]

Well, that's one thing I didn't mention. I did take it back and explained the symptoms. They adjusted the slave cylinder rod at the clutch fork and changed the transmission fluid and drove it around the parking lot a bit and claimed it was better. Yeah, that doesn't give me the warm fuzzies either. Anyway, I've been communicating directly with the service manager and he told me point blank that if it isn't better after a couple of weeks that they will drop the transmission again and replace that bushing. What worries me is that the master tech might be out of his depth on this. He looks like he is 25 years old. To be fair, now that I am in my mid 40's I think anybody under 30 looks like they are in high school...lol.