What is a syncromesch? and if damaged how costly to repair?

[MattyGreg05]

Hi everyone,
Can anyone please tell me what a syncromesch is?
If this was damaged what sort of problems/symtoms would there be.
Also how much roughly would it cost to repair and how easy would it be?
Cheers everyone in advance.
Matt

[west E]

i think its something to do with the gears, i only remember as my brother is a mechanic and he told me to do a test type thing when i bought my van.

ian

[MattyGreg05]

he told me to do a test type thing when i bought my van.

How did you do this?

[west E]

when i was driving down the road he told me to dump the clutch between changing gear. trying to fully remember, i'll speak to him and find out when he's back of jollies.

cheers

ian

[peasant]

Syncromesh is additional gearing in your gearbox that syncronises different gear speeds when shifting up or down.

If you try to shift up and it takes a good while (and a bit of "scratching") to get into the next gear, that would be an indication that there may be something wrong
If you try to shift down and can't get the gear in at all and the only gear that engages is the one you just left or the next higher one ...that also would be an indication that the syncromesh is kaputt.

No expert on fixing it, though ...

[The_blue]

If i recall, syncro alows you to change gear (smoother) when the engine and road speeds arn't the same. It's part of the grarbox guts.

http://www.singster.co.uk/mascot%20mar- ... 20(4).html



Synchromesh
If the teeth, the so-called dog teeth, make contact with the gear, but the two parts are spinning at different speeds, the teeth will fail to engage and a loud grinding sound will be heard as they clatter together. For this reason, a modern dog clutch in an automobile has a synchronizer mechanism or synchromesh, where before the teeth can engage, a cone clutch is engaged which brings the selector and gear to the same speed. Moreover, until synchronization occurs, the teeth are prevented from making contact, because further motion of the selector is prevented by a blocker (or "baulk") ring. When synchronization occurs, friction on the blocker ring is relieved and it twists slightly, bringing into alignment certain grooves and notches that allow further passage of the selector which brings the teeth together. Of course, the exact design of the synchronizer varies from manufacturer to manufacturer.

The synchronizer has to change the momentum of the entire input shaft and clutch disk. Additionally, it can be abused by exposure to the momentum and power of the engine itself, which is what happens when attempts are made to select a gear without fully disengaging the clutch. This causes extra wear on the rings and sleeves, reducing their service life. When an experimenting driver tries to "match the revs" on a synchronized transmission and force it into gear without using the clutch, it is actually the synchronizer that makes up for any discrepancy in RPM, deceiving the driver into an exaggerated sense of how much human skill was involved

[stuckin88]

If you have a crunch when changing between gear-usually 1st-2nd 1st -the linkage is correctly adjusted & the oil level is ok the syncro is worn & possibly the phosphor bronze ring is starting to crack---when the ring cracks all thru it will fall in half & the 'box is jammed & your stuck beside the road---unless you are capable of strippin & rebulding a gearbox you will need a recon 'box--about £400 for a 4spd + labour-may as well fit new clutch at same time

[MattyGreg05]

Thanks everyone for you responses.
You've enabled me to decide not to buy a van from ebay beacause it had a faulty synchromesch.
thanks again
Me