SM465 - Let's make sure it's right so I don't have to pull it, AGAIN (1 Viewer)

[mtweller]

So I got the 1st gear clearance issue (https://forum.ih8mud.com/40-55-series-tech/254764-tranny-465-gurus-cant-get-third.html) corrected by inserting a machined steel ring that is the exact thickness to hold the rear main bearing in place correctly.

Now, the 4th gear synchro ring is REALLY tight! I backed off the front bearing retainer bolts ever so slightly to alleviate some of the pressure and I can move the shift collar b/w 3rd and 4th by hand. However, if I crank those bearing retainer bolts down that synchro ring is tight as a tick. The other rings have a lot of room to move and are easily moved with one finger. Should this ring be the same way? I double checked to make sure the synch hub is not on backwards, but there is only one way it can be isntalled and still get the snap ring on the mainshaft (iirc). Anybody able to chime in on this?

Thanks!

 

[Pin_Head]

Nothing should be really tight. The input and output bearings are located by a snap ring on the OD race so that can't be the reason things are tight. Are the 3 "slots" in the synchro ring engaged in the 3 "keys" of the hub?

 

[mtweller]

Yeah, the ring can move as it should when I back just a little off the front bearing retainer bolts. Should there be a gap it sits in just like the other rings? It seems on the others, there are 2 machined surfaces that bottom out and the ring "floats" between the gear and hub. This ring seems to be susceptible to clamping between the hub and 4th gear (on the pinion drive).

Good Lord, does this ever end? It's looking eerily like I'm going to have to tear this whole mess down again - grrrrrrrrrrrr.

 

[mtweller]

Here is something I read on "the other board" :

Did you apply any oil to the syn when you put it together? Try rotating the mainshaft 180 deg and applying modest prybar help to the syn collar. If you cannot move it with modest prybar help, pull the main shaft and take the complete syn apart. You should be able to shift that synchro from 3rd to 4th and back by hand.

Sounds like it is no unreasonable for that synchro to be somewhat tight... or this poster does not know what they are talking aobout

 

[Pin_Head]

That post seems to be talking about the synchro shift collar, not the bronze synchro "brake" ring. You would never want to pry on the bronze ring. There is an upper and lower limit for clearance for the bronze rings. It should not be tight. The bronze ring has 3 slots that fit into the keys on the hub. If it is not installed right, it would be tight. Are you sure that it is seated right? It isn't easy to know without having it apart.

 

[mtweller]

Did a bit of head scratching and playing tonight. It appears there is about .035" of play between 1st gear and the case now, even with the bearing retained fully in the case. This tells me, if I am thinking right, the shaft is not pressed far enough into the rear bearing. This would position the rear portion of the mainshaft ~0.035" too far forward into the case, not allowing enough of a gap for the 4th gear synchro ring to "float" between the pinion and the synchronizer hub.

Assuming this is the issue, can I crank on the lock nut and reasonably expect it to seat the bearing furthe onto the shaft? I don't have a tool for that nut, so I guess I would need to fab one. I simply used a hammer and screwdrivers the first time....I know, I know, - jackleg as hell !

Thanks

 

[mtweller]

PS - Pinhead, I confirmed the 3 slots are properly aligned on the hub by removing the front bearing retainer and pulling the pinion far enough to see in there a bit.

 

[Pin_Head]

Yes, that would explain it too.

The rear bearing is driven on with a piece of tubing slipped over the end of the shaft and using a block of wood or soft metal to support the nose of the shaft inside the case. I don't know if the nut has enough oomph to draw the bearing up tight. Check out Don Kinzer's sm465 manual in tech links for the procedure.

http://www.kinzers.com/don/landcruiser/transmissions/sm465/doc/300x300/sm465.pdf