My T5 has an occasional 5th gear grind. It happens if I quickly shift into fifth. I was reading some other threads and someone mentioned that the T5 doesnt have a 5th gear synchro. Is this true? If that is the case is it normal to get a little grinding If I shift too quickly or at the wrong RPM?

I believe the 5th gear has a synchro and it's worn out, or something is worn out causing it to grind. Mine grinds going into 5th unless I shift really slow.
My old T5 in my 86 never ground 5th no matter how fast I shifted.

There's definately a synchro on 5th gear and it sounds like yours is worn out.

Yeah Thats what I figured but In an old post which I am having trouble finding now someone mentioned no 5th gear synchro so I figured it might be the reason.

Is there anything I can do to stop it from getting worse? Should I switch back to non-synmthetic ATF because it seems like it might be doing it a little more now with the synthetic.

There is DEFINATELY a synchro on 5th. I have rebuilt my T-5 and replaced the synchro on 5th.
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You can try it. Are you saying that it started when you switched to Synthetic or are you saying that it got worse when you switched?

It had already been occuring once in a while(~1/month) with non-synthetic, but It seemed to have gotten worse with the synthetic and occuring ~50% of shifts. However today I was driving it around and it didn't do it at all, so maybe Ill keep the syhnthetic for a little longer and see if it still does it a lot.

I amstill having this problem and I was wondering how hard it is to change the 5th gear synchro. I might just have a tranny shop do it because I am working about 80hrs/week now and don't have time. Any ideas how much it should cost assuming it is just the synchro?

Not that hard, but that's probably not your problem. 5th still uses a brass synchro, even on a WC T5. My guess is the sliding sleeve is torn up. Here's the trick, flip it over and use the good side, because it only works one way for 5th gear. You can do the repair by just removing the tailshaft housing. You won't affect the endplay setup, so the hard part of setting up a T5 isn't even an issue.

Its wierd but I changed the fluid back to nonsynthetic(Valvoline Dexron III) and it really helped stop the grinding. I didn't think it would be such a big difference because the synthetic fluid said that it met Dexron III specs. Now I only get the grinding if I rev it pretty high before shifting into fifth which I don't do often anyway so I think I'll just leave it how it is. No more synthetic Fluid for my Bird.

Dragging this back from the dead because I had the same problem and fixed it. I rebuilt my T5 (1990 305 model, WC) which included replacing the 5th gear brass syncro. yes there is one. Freshly rebuilt it would grind going into 5th over 2000 rpm. I discussed the problem with two transmission shops and they both told me the same thing, the cone the brass syncro ring runs against on the 5th gear needs to be "prepped" when rebuilding. It becomes highly polished over time and the syncro will no longer grab on it. One shop said to use 120 grit emery paper and the other said to use 600 grit emery paper. I took mine back apart and rubbed 320 grit emery paper across the face of the cone to remove the shine, replaced the brass syncro ring just in case, and reassembled it. Now it works great no grinding at all.

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Hope this helps someone else out.

Thank you for the information. I think it is never too late to add more useful information to this type of topic as others like me will find it when searching for a solution to the same symptoms. I am the original owner of a 1990 Formula 305 LB9 T5 with 44K miles. Mine has had this problem for a long time. I was happy to find this thread with the postings indicating what the problem may be.