Join Date: Sep 2006
Location: Las Vegas, Nevada
Well this is common I worked in a trans shop for a few years. It could be couple of different things.
1. The oring has gotten hard and you can swing buy most trans shops and they will sell you one usually pretty cheap I also recommend putting some clear silicon on like GE window sealant that's what we use to do
2. I also have seen the housing leak around the shaft the speedo gear attaches to. On this part I'm not sure if the inner seal is replaceable like on GMs but you can find plenty of those at a salvage yard. It doesnt have to be mn12 it can be any Ford rear wheel drive close to the year of your car. Just replace the oring on the used unit and use you speedo gear. The speedo gear comes off easily it self explanatory when you see one.
Hope this helps.,
No o-ring there, just a paper gasket.
-1996 Pearl White Thunderbird 4.6 Sport 4v with many mods:
Current Best: 13.583 @ 103.74 10/2014.
227hp/241tq measured on calibrated mustang dyno, tested at full vehicle simulation with inertia enabled, no number skewing.
-2001 White Ford F-250 Super Duty 6.8 V10, 4-door, 4x4, Limo Tint, BFG KO2's, Bilstein 7100 Remote Reservoir Race Bypass Shocks, 6" Spring lift, Kenwood Double Din, K&N Intake, FlowMaster Exhaust
Amber_Murder's Daily Driver.
-2005 White GMC Sierra 3500 6.6 Duramax, Dually, 4-door, 4x4, Limo Tint, BFG Commercial T/A's, Rancho RS9000XL Shocks, Kenwood Double Din, K&N Intake, Banks Monster Exhaust
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