Synchro rings

[nutcase]

Morning :)

Any reason not to re-use synchro rings like this?



The box was out the car when I got it so I have no idea on its shifting quality. There's plenty of meat left and they feel smooth when manipulating the assembly. The book shows no guide on what constitutes a heavily worn synchro ring

[DeLorean]

How does the hub look? That looks like it's probably serviceable, but if you have a better one, use that. It's false economy to replace every syncro ring that has a little wear, hard to say but that unit looks like it will still operate just fine.

[nutcase]

I have no spares at all - it's a 1992 box and all my others are ealier with the different rings.

Best pics I have at the moment

[DrewP]

It's hard to tell from a photo, but those look pretty decent to me, the hub better than the syncro ring, but they look OK.

[Jordan]

We had posted up a SAAB factory training/tech manual which explained what to look for on trans overhaul...IIRC it had some detail on what to look for specific to the syncro assembly. I think the dog/muff profiles are more critical to good engagement.

I'll see if I can find the link.

http://saabrally.com/downloads/SAAB-900 ... Manual.pdf

[DrewP]

Yes, the corners on the angled tops of the dogs, along with how worn the tapered face of the ring is where it slides into the receiving side of the collar.

The tips of the dog teeth ideally should be nice and sharp, when they are worn out they get rounded off at the tops and on the faces of the teeth, and mash past each other rather than grab. That's part of what can give a crunchy shift. Friction on the tapered faces does work to match the speeds too, it's got to sync the two hubs enough that the teeth can grab each other to align the drive dogs for engagement.



This is the 5th gear hub of a really worn '82 5-speed, sorry for the bad quality but you can sort of make out the shiney-rounded profile at the insides of the teeth on the receiving collar, both sides will start to look more and more like that with more and more miles.

[DrewP]

That's a good manual, I had not seen that before. Thanks for posting. Syncro condition is pages 44-45.

The English in it is so good!

[Geoff]

That's a good manual, I had not seen that before. Thanks for posting. Syncro condition is pages 44-45.

The English in it is so good!

Note the copyright: SAAB Cars USA, Orange, CT.
We done speak the English bestest!

I think John Moss had something to do with that manual.

[nutcase]

Brilliant, thanks peeps! Looking at that manual (the UK Saab transmission training manual isn't a patch on that one!!!) my hubs and rings are ok. Not great but ok. However, my 1-2 fork is toast Says 0.1mm per side, I have 0.3 - looking at it there's not much of the radial grooves left...

3-4 and 5 look ok I think. The silver-grey coating is *just* gone from it, my vernier says 0.1mm missing total.

[nutcase]

Piccies say a thousand words :)





Predictably the brand new 1-2 fork I have is for earlier boxes. Oh well, on the hunt :)