Just finished putting the trans back together, run it through the gears, and third doesn't engage fully, pops out. When it was on the floor and I tried shifting through the gears, all were smooth and engaged. Is it possible that the clutch engagement is too low? On my old clutch I had to adjust the pedal cause it would catch too low. Now with the new one, maybe I have to set it back? I doubt that's it but, it's worth a try. Another thing, when we had the trans apart cleaning it out, a small pin fell out. It's maybe 1/2" long, 1/8" thick, round. For the life of me no one could figure out where it fell out of.

 

before anyone asks, I had the FSM and FAST diagrams in front of me and I checked for every single pin they showed, they were all in place.........

 

popping out of gear is most likely a bad blocker ring. did you check to see if the grooves on the inside were still sharp? also, since you mentioned the clutch, clutch pedal should have about an inch of free play before it engages. if it doesnt it probably needs to be adjusted.

EDIT: could the 'pin' possibly not be a pin, but a roller bearing? aka: was there any grease on it(at all)?

 

not baring, I thought it was too but the rollers on the old bearings were bigger. All bearings except the differential bearings, were replaced. Didn't have problems with popping out of gear before, so it must be something I did. There is no free ply in the pedal, I have resistance from top to bottom. Like I said, the gear doesn't feel like it fully engages, maybe halfway...

thanks for the help,,,,,

 

well if you end up taking it apart again, check the 3rd gear blocker ring! most popping out of gear problems are because of a bad blocker ring. just cause it didnt do it before, doesnt mean its not the blocker ring.

 

The reverse gear lifter assembly pivots around an axle that about 3/8" diameter and inserts from the outisde of the tranny case. There is a pin used to lock this axle into the housing - I suspect that's what's left out.

I would guess that if you left 3rd gear and 3rd synchro alone during your rebuild, that the synchro is fine. If you replace 3rd synchro, are you sure you have the same kind? IIRC 3rd synchro can come in a double cone and single cone design.

Dave

 

synchros were left alone, looked brand new compared to brand new ones.

it might be that pin..........

 

Wait a sec - 1/2" long, 1/8" around - it's the pin that goes inside of the 3/4 shift rod. It's called an interlock pin. It would certainly explain why it's popping out of gear.

The one I was talking about earlier is nearly an inch long. Different pin.

Dave

 

What kind of shape was the 3rd/4th sleeve in? If it was significantly worn down that could be the cause of your car popping out of gear. Of course if it was significantly worn down you would have probably noticed it but who knows.

the pin sounds like one of the interlock pins to me, they are a little less than half an inch, about 1cm long, and there are a couple of them in the trans. take a pic of the pin and i can tell you if it's an interlock pin. or measure it, i had to measure one once and iirc it was 10.xx mm long. i can measure one tomorrow at work if i remember.

 

pic coming really soon.........

 

I agree with willard00. Most likely a roller bearing if it just "fell out" of no where.
Only roller bearings fell out during my last manual tranny rebuild (Mustang btw, sorry).
Of course a worn blocking ring will cause a shifter to pop out of gear but only
a roller bearing fell out of place during my rebuild because I hadn't greased them all
into place. First gear and reverse are usually tied together. Third gear isn't likely
to have a relation to reverse, too tall for reverse. Double check your roller bearings
if possible.

 

There are no needle/cylindrical roller bearings in this tranny. There are tapered rollers, but unless you damage the cages they won't pop out, and if the rollers do pop out they will by conical, not pin shaped.

As well, the synchros on these trannys don't go bad overnight unless some major thing happened to it, and I thin the OP would have explained that.

The interlock pin is what makes the interlock mechanism work, and it has a lot to do with keeping the shift rods in a particular gear. He's going to need to take it all apart, but IME buying a synchro is a waste of money at this point.

Dave

 

the old bearing we took out we had to cut it up so all the rollers did fall out, this was outside the case though and the rollers in that bearing are bigger than what I found. Here's the pics, my new camera isn't in yet so cam phone pics will have to do. They are blurry but you can see the size of it and the rough shape of it........

 

Yeah, that's the interlock pin. I just verified the dimensions.

Check the FSM page MT-12, item 26.

 

mkay, how the hell did that fall out? wouldn't the forks have to be out in order for that to fall out?

 

I'm guessing it was never inserted in the first place. You slide it into the cross-wise hole in the bottom end of the 3/4 shift rod, and then it's trapped on each side by the check *****.

Could you have possibly pulled it out with your magnet when you were inserting the check *****?

 

hmm, I doubt it, but you never know.


in that pic, in order to separate the two halves of the trans case, you have to remove bolts 30 and 34 and the one holding the reverse gars shaft and gear in place. 30 and 34 come out with a spring and check ball each. The plunger is separated from those. That plunger could have only fallen out if the fork was lifter up enough, right?

 

Yes, that's one scenario. Another is that if either of the other shift rods is pulled out and the check ***** fall loose, that the interlock plunger could come out also.

Another scenario is that it was loose in the tranny before the rebuild. There are a few little pockets where stuff like that can hide. What color was the sealant around the case faces? (Nissan original is grey).

In any case, there is only one interlock plunger and somehow yours is outside of the tranny now.

Dave

 

it was grey. Currently we're using toyota black sealant....