syncro crunch 'problem' with new syncro's

[jazig.k]

i recently rebuilt my 3.0lt 75 gearbox.
new syncros for 1,2,3 & 4.
doesnt crunch like it used to...
but, it seems to have reversed the action required to get it to crunch going to 2nd.

6500rpm, and a very quick change to second, and its awsome! no crunch at all! but cruising around town, 2250-3250rpm [aprox] and itll crunch with a slow/gentle/average shift.

anyone?

[jazig.k]

anyone with any ideas?

[Ozalfaracer]

G'day Jazig. If I get some answers to a few questions it might help to diagnose the problem. How many kilometers since it was rebuilt? Did you replace the synchro sleeves as well as the synchro rings? What kind of trans oil did you use (it makes a BIG difference)? Does it graunch badly or is it just a little sticky?

I've had a few transaxles that were pretty notchy after a rebuild until they had a few miles on them, it's just all the new surfaces getting used to each other. As for which trans oil to use, there's a buch of opinions but I found the Redline 75W90 NS to be the best and I've tried most options. The NS has a lower "friction reducing additive" content which allows the synchro's to work more effectively. It also works well with the LSD friction plates.

Anyway, give us some answers, I'm sure some of the other's will pipe up too.

Cheers, Rick.

[NZAlfa75]

Did you replace the synchro teeth on the gears themselves as well? The teeth on the two gearboxes I've had apart were well worn also.

[101 Alfa Mike]

Quote:

6500rpm, and a very quick change to second, and its awsome! no crunch at all! but cruising around town, 2250-3250rpm [aprox] and itll crunch with a slow/gentle/average shift.