I hope I'm not wasting anyones time with this but I need some help and/or advice. I have a HP500 merc motor with an ITS box with the XR drive. I have replaced the upper gears in the XR twice this year due to a broken tooth causing problems. I have heard there might be a "hardening" proceedure out there to extend the life of the gears or is there a better replacement? Whole drive or something else. Any help would be appreciated.
Md

I've had a tooth break off of one and
junk a case out.

I've had the cone shear off of the gear on
the replacement upper from problem mentioned
previously.

I've had a couple of them simply just chunk out
the gear teeth.

I had 2 sets cyro treated at the same time,
one set still looks good, the other set started
to chunk out.

I've convinced myself the merc is having these
things made in China

So, no, you're not alone.

Thanks for the info.
Md

try this.. peace of mind.. http://www.arneson-industries.com/

Can a set of X drive gears be installed in place of the XR gears since it has been noted that the XR gears are known for this problem?

Something in your setup / assembly is not right. You should not have any problems with that hp. Who is building your drives?

I have lost both upper sets in my XRs also. They are 2005 model and I have about 130 hr on them with 600hp in a 32 Fever. They were factory set up and both lost a tooth or two...Im rebuilding my second one tomorrow.

Nordic95

Rolling torque has been WAY off in the last 4 new drives that I have dissasembled and checked.

Rolling torque & pinion deph off on recent drives disassembled in our shop, I have XR with high HP doing well.

I have done exstensive testing on hardening,cryo treating and micro polishing mercruiser gears and I believe in its benefits. It will help a set of gears last longer before they start to pit,shed metal and slowly fail in extreme applications BUT unfortunately it does NOTHING to help prevent a merc gear,especially a upper from spitting the teeth off. Smitty