Sam,

BTDT.

Tools/materials:

8mm x 1.25 'Keen-sert' or 'Time-sert' (NAPA stocks 'em)

New bolts and wavy washers (8mm x 1.25 x 25mm IIRC)

Appropriate drill and tap. NOTE: the tap is an odd-ball size.  12mm x
1.25? You'll probably have to order it.

Tapping fluid for aluminum (I use Tap-Magic)

Drill motor (variable speed)

Loc-tite Kleen 'n' Prime

Loc-tite 271

Small ball peen hammer

Tap handle

Cost?  If you got the drill motor and the hammer, about $45.

Procedure:

First, look it over and make sure that you can get a straight shot at it.

If you can,
Remove exhaust pipe
Remove tin
drill and tap hole using plenty of tapping fluid so as to get
'perfect' threads. (Straight is critical!!!)
Wash hole thoroughly with Kleen 'n' Prime.  Get *ALL* the chips out!
Ditto the insert
Put a drop of the 271 (just a drop! a little goes a long ways!) on the
insert and screw it in until the threaded portion is a thread or so
below flush.
Gently hammer the splines in.
Let it sit until tomorrow so the Loc-tite cures.
Reassemble.

If you can't get a straight shot at the hole, you'll have to lower the
motor. Might get away with disconnecting the shifter and lowering the
front of the trans to get access.

Have fun! It's not difficult, just 'fiddly', Take your time and
'measure twice, cut once' When I had to do mine, L/H rear, I did both
of 'em. Forever Fix!

Jim Arnott
WetWesties
Union, OR