Manual Transmission T56 | T5 | MN12 | Clutches | Hydraulics | Shifters

3rd and 4th synchros? Advice please

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Old Feb 25, 2010 | 07:44 PM
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Default 3rd and 4th synchros? Advice please

Okay, heres the deal. I bought a used T56 about 8 months ago. I was told by the previous owner that the trans was built by RPM with billet keys, bronze fork pads, and a steel 3-4 shift fork. The trans worked fine for a few weeks, then I started having problems. Now it grinds 3rd gear on downshifts and 4th on upshifts. If I am goin through the gears and I get to 3rd or 4th and with for the revs to "match" it will "fall" in gear, which is expected. It seems to me that the synchros are bad in those gears, but It just seems strange to me that it happened in 3rd and 4th. I lost my previous trans to a broken stock 3rd shift fork, and I bought this trans cheaper than I could have fixed my old one for. If I do just need to replace the synchros, how involved is that process. Does the trans need to be torn completely down? I need to fix it because right now it is the difference between an 11 sec run and a 10. Thanks in advance.
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Old Feb 25, 2010 | 07:52 PM
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The trans has to be taken completely apart to replace the 3-4 blocker rings.

Will also give you the peace of mind to see that all those upgrade pieces are in fact installed like the seller said.
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Old Feb 25, 2010 | 07:56 PM
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Well its too late to do anything about it. Nobody has seen the guy since around that time. It has nothing to do with the trans, just a coincidence. I knew the trans had to be taken apart. I guess what I was getting at is will this be something I will be able to do in my shop. Ive heard stories about how hard rebuilding these transmissions are, but I wasnt sure if all that info would be applied to just changing the blocker rings.
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Old Feb 25, 2010 | 08:02 PM
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Didn't mean to imply going back and doing anything to the seller, just that if you're doing a 10sec run, you want to know for sure that those parts are there.
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Old Feb 25, 2010 | 08:04 PM
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Yeah I know. I wouldnt anyway. It was an as-is thing. Hell, I bought it cheaper than I could get a used stock one for anyway.
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Old Feb 25, 2010 | 08:46 PM
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I dropped my transmission last fall. I have never tackled anything like that before, but my gf's dad helped me and he had done it a couple of times. He found something online that told him exactly how to take it apart/put it back together. There are a lot of parts though, and it would be easy to get confused. We laid them out on a table in the order they came apart.

My 3-4 synchro keys were broken, and it was making my transmission slip out of 3rd. Put in billet keys, and now it grinds sometimes going into fourth...
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