Join Date: Dec 2008
Location: Tyler, TX
Thanked 407 Times in 347 Posts
The AT545 does indeed use an SAE #3 housing, but the 7.3L has a #2 to #3 adapter bolted between the FW housing and the trans, so you *can* use a MT 643 with their #2 SAE housing.
The AT is a durable trans, and IMO you should NOT spend the major $$$$$$$$$$$ to change it for a different trans for any reason, especially for a lock-up converter, it's simply not worth it, not at all.
'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote - Benjamin Franklin
I vote for LIBERTY!