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Posted by: nine9three Oct 7 2013, 04:48 PM

The transmission was out and we replaced three syncro rings and 1st gear dog teeth. The ring and pinion looked great with very little wear. The spider gears though were very shinny. They looked worn, but no broken teeth. Buttoned everything up and now I have noise. It is not a R&P noise but a loud sshhhhhhhhhhh type of noise. I can not hear it very well in 1-3 gear with 4/5 being louder. Any thoughts? How long for new syncros to break in? I need quite a bit of tension against the shifter to get into gear. I bought the aftermarket syncros from the bird at only a slight discount from OEM.

Posted by: Jon B Oct 8 2013, 01:22 AM

Differential gears would only make noise when turning, but rarely go bad in normal use. It's possible you assembled something incorrectly on the pinion stack, or shift forks aren't properly adjusted. Reverse op sleeve cannot be set too near idler reverse teeth.

Synchros should be measured for installed outer diameters, especially when using Rauch & Spiegel parts. OE synchros are Goetze.

Jon B.
Vista, CA

Posted by: Dr Evil Oct 8 2013, 12:47 PM

Does the noise happen dependent on engine RPM or wheel RPM? This will give an idea what part of the gear box is involved. What makes it worse or better?

Posted by: nine9three Oct 8 2013, 09:29 PM

Wasn't aware that synchos required measuring whether R & S or OE?



I would say that the noise is related more to engine RPM than wheel RPM.

Some additional observations. The noise is getting better??? It is most noticeable when decelerating at higher RPM and it definitely not a whine. I should mention that the transmission was rebuilt and installed with a brand new Sachs PP,Clutch and T/O bearing. Initially had a very hard time adjusting the clutch free play. Wondering if clutch was adjusted too tight? Is there a break in period for fingers on the PP? Also, absolutely no noise when taken out of gear and coasting at any speed.

Posted by: Jon B Oct 8 2013, 10:11 PM

They should always be checked.
Very important with Rauch & Spiegel parts, they're often out of spec.

Synchro diameter installed:
2.997" to 3.011"
76.12mm to 76.48mm



Jon B.
Vista, CA

Posted by: nine9three Oct 8 2013, 10:19 PM

Too late for that now. replaced 1st thru 3rd and all are fairly tight. Would that not be normal for new synchros?

Posted by: Jon B Oct 8 2013, 10:42 PM

Possibly, but shouldn't be too dificult to shift, even with new synchros.

Make certain your clutch disengages completely when shifting. After driving a while with everything warm, bring car to complete stop, engine running, and shift into reverse. If you cannot without grinding, then you have a clutch, firewall or pilot bearing issue.

Jon B.

Posted by: nine9three Oct 8 2013, 11:43 PM

No problem with that. Also, I know its a no no, but I can shift down to first without issue (no grinding).

Related but slightly OT, what is the procedure for installing the shift console to the shift rod. Might this be related?

Posted by: Dr Evil Oct 9 2013, 07:40 AM

While the antiquated manual does say to measure the synchro rings, I have never done this and have had no regrets. However, some of the new ones you buy are very stiff and do make shifting hard. What can you do about this? You going to send back all "out of spec", too big bands? Buy from two manufacturers and compare? Perhaps. Pelican offers two brands and likes to call one a "race" type. I am still unclear as to what makes the ones "race" over the others. I do see that the new ones, all of the ones I have seen over the last few years, have been way stiff and larger than spec. They compress so overall dia is not an issue if they have enough give, but the wider dia plus the stiffness have caused headaches. I use good used ones whenever I can as they shift like butter, cause no issues, are cheaper, I already know they fit, etc.