4th/5th gear replacement on a 308 - Ferrari Life
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post #1 of 3 Old 05-13-2007, 02:55 AM Thread Starter
Maranellohouse's Avatar
Join Date: Apr 2006
Location: Northern Ireland
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4th/5th gear replacement on a 308

My gearbox is getting a little crunchy changing from 5th to 4th and reading the workshop manual I see it's reccomended that both 1/3 an4/5 syncros should be replaced every 30 kilometres. My cars just gone 60k so I think it's time to have it done.
I was wondering if anyone has done this work themselves and is it a hard job. I do most of my own work but have never tried this before so any guidence would be greatly appreciated.
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post #2 of 3 Old 05-13-2007, 08:15 AM
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Location: Phoenix, Arizona
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Transmission Synchros

According to my maintenance schedule, the transmission FLUID should be changed at 30K, 60K, etc., not the synchros. Replacing synchros is only done when there is a problem, and is a major job. You have to remove the engine/transmission as a unit, then separate the two pieces. Once you have the transmission on the workbench, the rebuilding process is not that hard, assuming you've done other manual transmissions. You do need a couple of special tools, called ring nut sockets, to disassemble the transmission. There are three shift forks, one for reverse and first, one for second and third, and one for fourth and fifth. The synchronizer rings, or blocker rings, are over $500 each from Ferrari, although GT Car Parts here in Phoenix can get them for $257. Bearings are proprietary, and are hundreds of dollars each. I can't even imagine what gears or the synchronizers themselves cost. Still interested in doing the job?

Before you freak out, I'd try one other thing first. There is a sleeved rubber bushing on the shifter shaft a couple of inches from where the shaft goes into the transmission. The rubber deteriorates and can keep the shifter from working properly. The bushing is about $20 and can be done in the car. It is a little tough to do because it it is located right above a non-removable frame piece. Might be worth the effort, though.

And before someone else suggests it, you might try some Red Line gear oil first. If the synchro really is bad, it won't help, but it's probably worth a try.

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Last edited by Ferrari328GT; 05-13-2007 at 10:03 AM. Reason: added last paragraph.
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post #3 of 3 Old 05-14-2007, 12:24 AM Thread Starter
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Hi Steve, thank you for your reply. I'll try the oil first to see if that makes any difference. I was intending on taking the engine out at some point to clean it all up and planning on tackling the box then.

The shifter shaft sounds like a good move to.

Youv'e been very helpful, thank you again.
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