The transmission housing has been through a few revisions on the Dyna in regards to the hole that the long bracket bolt threads into. The newer models I recall have more of a shoulder to the bolt and the threads are recessed in the case. One of the issues is not having loctite on those bolts so they back out and shear off. I'd recommend using ARP fasteners as well. I did a lot of research back when I replaced mine with the early style case and ended up using the following to replace the 3 bracket bolts from allensfasteners.com:

Item 1
Product ID: 0518
Product Name: 5/16-18 HEX FLANGE BOLT SS ARP
SIZE: 5/16-18 X 1-1/2 HEX CS ARP (SS)
Product Price: $2.38
Quantity: 2

Item 2
Product ID: 0518
Product Name: 5/16-18 HEX FLANGE BOLT SS ARP
SIZE: 5/16-18 X 1-3/4 HEX CS ARP (SS)
Product Price: $2.44
Quantity: 1

Over the winter I broke my transmission case (another story. .) and installed a new one that's off the late model bikes (I think 2013+). Now I'm using two ARP fasteners into the transmission cover as above and the supplied shoulder bolt that came with the case for the longer bolt.

The case has been through various revisions and PN's but the latest is 34747-06C:



They added two mounting holes for the FLD exhaust bracket. Additionally the hole (not shown) for the top mount of the exhaust bracket has been changed from fully threaded to having a shoulder, then threaded. The shoulder is about 1/2" deep into the hole before the threads start. New bolt there as well. You can see the supplied HD bolt in the picture as well as the two ARP bolts I'm using going into the cover.

Finally, the instructions that come with the latest case are here:

http://www.harley-davidson.com/en_US...ts/-J05490.pdf

 

My dealers and HD have now sorted mine out, out of warranty but done as good grace. The casing was so badly damaged from the failed bolts it had to be replaced. 16hrs on the shop bench and a total bill of £2600! only charged me £196. So thanks to a dealers that pushed it with HD its all done, but my faith in the brand has been shaken a bit. Interestingly the case was replaced with one without the FLD bolt holes exactly as previously fitted. The bottom hanger bolt only holds in with a tiny amount of thread, i think this is the route of the problem.
I will be changing out the stock system and fitting new decent bolts ASAP though!

 

Recently bought a 2011 FXDF with only 4,000 miles - really nice machine. Some riding buddies said they heard a rattling when I rode up the other day. Bottom nut gone. Top nut sheared off still attached but would only spin. Middle bolt broke while I was trying to tighten it. Since it's out of warranty I had to pony up the bucks so rather than put a band aid on and have to deal with the same problem I put Vance and Hines Staggered Short Shots on and went with a stage 1 mod as well. After the dyno tune it's like a different bike now! Now I have to deal with the stock tires cupping!!!!!!!

 

mattVA,
Would this also be a recommended fix, even if I've not had the issues with my 09 FB?
-Donald