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Bad synchros? How can I tell? by slade1274
Started on: 06-08-2006 08:04 PM
Replies: 6
Last post by: Pyrthian on 06-09-2006 09:37 AM
slade1274
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Report this Post06-08-2006 08:04 PM Click Here to See the Profile for slade1274Send a Private Message to slade1274Direct Link to This Post
I bought the car with the only intention being to do the L67 swap, so no skin off my back that it didn't run. The owner said that the trans also had issues and indicated that someone told him it was bad syncros. Well, as I broke things down to prep for the swap, I noticed that the pressure plate was missing a half dozen teeth where the throw out bearing hits it. Also, the fluid didn't look so good when I drained it. Two things that I know can cause the prime symptom the prev. owner spoke of- shifts fine when sitting and doesn't like to shift when running. I have no way to see since it doesn't run- so I was lucky enough to find a Beretta GTU at the pick-n-pull, after 3 hours fighting the damn thing, it's getrag was mine for $60. Now, since WCF is taking their time getting me the motor mount and flywheel, I figured I would use one of the great resources we have available, Rodneys how tos. I "cracked" the case on the stock getrag to get a look see, and low and behold, it looks brand new inside. Only slight shavings on the magnet, so slight it was barely enough to coat my index finger- way within tolerance of typical gear break in- not break up. Below are a few pics, where do I look to inspect the syncros? Help please!



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Tom Piantanida
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Report this Post06-08-2006 08:26 PM Click Here to See the Profile for Tom PiantanidaSend a Private Message to Tom PiantanidaDirect Link to This Post
I'd say your shifting problems - okay when setting, hard to shift when running - are related to the clutch not fully disengaging due to the obvious wear. Bad synchros usually cause "graunching" when you shift. That is, if you don't shift slowly enough to give warn synchros time to do their thing, the transmission grinds going into the next gear.

One final word: The Beretta transaxle uses a different type of vehicle speed sensor (VSS) than the Fiero. You can split the Beretta case and install the correct Fiero VSS, or use a "speedometer module" to make the Fiero speedometer and ECM "understand" the Beretta VSS.
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slade1274
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Report this Post06-08-2006 08:34 PM Click Here to See the Profile for slade1274Send a Private Message to slade1274Direct Link to This Post
Thanks for the input, but I'm hoping not to need the spare trans- can the syncros be seen from these pics or are they inside one of the assemblies? Give me a 4L60E and I can tell you all the parts in it, but this manual is another story entirely. I'm all but clueless.
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Delphince
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Report this Post06-08-2006 11:09 PM Click Here to See the Profile for DelphinceSend a Private Message to DelphinceDirect Link to This Post
 
quote
Originally posted by Tom Piantanida:
I'd say your shifting problems - okay when setting, hard to shift when running - are related to the clutch not fully disengaging due to the obvious wear.


In my experience, clutch disengagement problems will cause more difficulty getting into first or reverse than gears while driving. You can match revs while moving and shift without the clutch at all, while parked a spinning transmission simply won't engage.

A good way to tell if it's clutch or synchros is to bring the car to a stop and try to put it in first. Once it goes in, keep the clutch depressed, and pull it back out of gear. Wait a few seconds, then try and put it back in. Keep in mind, this is all done with the clutch never being released. If the gear slides back in, it's a synchro problem, if the gear fights you again, it's clutch-related. Granted, this doesn't cover the other synchronizers, but it gives you a definitve idea of the condition of your clutch system.

------------------
LIFE IS MADE OF OBSTACLES AND CHALLENGES — TO OVERCOME THEM IS TO PROGRESS.

DRIFTING — IT'S NOT THE FASTEST WAY AROUND A CORNER, BUT I'LL BE DAMNED IF IT'S NOT THE MOST EXCITING.

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slade1274
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Report this Post06-08-2006 11:19 PM Click Here to See the Profile for slade1274Send a Private Message to slade1274Direct Link to This Post
Again- trans is not in a working car. How can I check the synchros by looking at the internals while the case is split?
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SCCAFiero
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Report this Post06-08-2006 11:48 PM Click Here to See the Profile for SCCAFieroSend a Private Message to SCCAFieroDirect Link to This Post
I just test drove my 88 with a getrag after doing my first rebuild on it. I had a racing buddy with a press help me with the synchros (actually blocker rings) replacement. You would need to pull the gear clusters out of the case and then compare the side to side gaps between the blockers and the other gears. Also, on mine the 5th gear blocker was galled to the shaft so badly that all the brass was embedded on the steel shaft and the blocker ring was showing steel. There is no way you can see that kind of damage without removing the rings from the shafts. It took about 20 minutes with a wire brush on a bench mounted motor to get the brass off.

If mine survives 4 hours of endurance racing at Homestead Miami Speedway this weekend I may offer a bit more advise. Other wise, I will just say the rebuild was challenging but not too bad. It felt great around the block at 20 MPH but 120MPH on a track is a totally differant animal.

The worst part of the whole rebuild is I got a "robbed" rebuild kit that was missing the 1st and 2nd rings and 1 seal. At least the company I bought it from made up for it with a cross country next day air shipment so I could get it done on schedule.
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Pyrthian
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Report this Post06-09-2006 09:37 AM Click Here to See the Profile for PyrthianSend a Private Message to PyrthianDirect Link to This Post
 
quote
Originally posted by slade1274:

Again- trans is not in a working car. How can I check the synchros by looking at the internals while the case is split?


slide the synchro back 'n forth, to see if it moves smoothly. it should slide back & forth & have a "clicky" feel when it engages on one side or the other. a bad synchro would give problems consistantly, not just moveing/not moving. sometimes a synchro will "jam" and the only way for it to "unjam" is if its moving. and synchros normaly are either broken or not broken - no in between - theres no "going bad" - they just break one day.
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