Engine/Transmission (1998.5 - 2002) Who here knows NV4500's...

[ScottWright]

Ok about a year ago (maybe longer), I had broken an output shaft in my '01 2wd QC truck. At the time, the truck was basically stock, but from the looks of it, the shaft had been cracked for a very long time.



Anyway...



So I got a good aftermarket billet shaft for the thing, and went on my way for the trans rebuild. Now I will say first of all that I have NEVER done a manual trans in my life. I've probably done 50 automatics, but never a manual. I've set up rear ends, built race motors for myself etc. . so I'm fairly well versed, just not in the manual rebuild department.



I didn't have a service manual for an '01, but I did have one for my Dad's '95. Although they were close, they were not exact. I used it as a guide the best I could. All in all I felt very confident when I put it back together, because in the end, compared to an automatic, they are very simple devices.



Of course, I put the trans in the truck, and it grinds 3rd gear. 3rd gear, and only 3rd gear. Evey other gear shifts fine. It's not like the syncro is marginal, it's like it's completely missing all together. It doesn't even make an attempt to gear speed match on a 3rd gear shift. All kidding aside, I know the syncro friction is in there, but it acts like it's not. It's that bad...



So anyway, at the time I didn't have time (or patience) to pull it back apart, so I've just been driving it like that for the last year. I've become an incredible driver, (double clutching, speed matching, etc... ) for the most part 99% of the time, I can drive it without a hint of grind... :-laf



However, it is screwed up, and I'd like to fix it. The only thing is I can't have the truck down for weeks trying to figure out what the matter with it is.



Anybody have an idea what I could have done wrong? I have a couple suspicions.



1) I never put a new 3rd gear on it. The output shaft broke right between 3rd and 4th, and I had to tap the gear off the shaft. It may have "bugger'd" up the 3rd gear, but I didn't think that would make too much of a difference.



2) There was a very thin what appeared to be "blue spacer" that was somewhere in the 3rd/4th gear assy (sorry it's been to long now to remember exactly where). The '95 service manual didn't say anything about it, and I couldn't find anything on it at the time. I assumed it was just a front shim for the overall end play, but the endplay came out right in the middle of the factory range, so at the time I assumed I didn't need it.





Thoughts? Help!?



Thanks guys,

Scott

 

[SRadke]

There is a plastic wear washer in the middle of the stack there. I don't remember exactly where it was either. My guess is you got something inverted in the 3 gear syncro stack. You may even be able to see it (see it, not fix it) by simply pulling the top off. I'm assuming by your post you did not put new syncros in it when you had it apart?

-Scott

 

[ScottWright]

Well I was thinking that, but I can't see if I had any of the 3rd gear syncro assy parts inverted, that it would have even gone back together?



You are correct, I did not put syncro's in it. The friction material itself looked brand new, and it shifted perfect before it broke the output shaft...



You're thinking I might be able to see whats going on by pulling one of the side covers off?

 

[SRadke]

You may be able to see it through a side cover but I don't think so. You'd have to pull it and take the top off. Fortunately with a 2wd it's not bad to do.

The only part in there you can easily get backward is the sliding collar which I expect would affect 4th gear as well. It would do as you describe if the syncro were not installed at all but leftover parts (especially large parts) tends to raise a red flag.

The only other think I can think of is if you have too much space in that stack. A snap ring in the wrong place, something not slid on a spline all the way... something like that. I think it would be possible to do that and still have the endplay land close to spec.

 

[ScottWright]

Yeah I think in the end I'm just gonna have to take the thing apart, and look real hard at it. As I remember, 4th gear is the very last one to go on. That one I had to tap on because the splines were "nicked" from where it had broken the old shaft. If anything, that could be holding up the total stack height, but like you said, You'd think it would show up in 4th gear too.



Just kind of strange in general. Who knows, maybe that syncro frictions laying behind the workbench somewhere...



Thanks for your help.

Scott