How do I replace a rear seal in a 1966 ford f-100 with a 352 engine?

I wouldn't be surprised if you didn't have to remove the engine/transmission, split the trans from the engine, remove the TC or clutch/pressure plate, (you should have drained engine oil and auto trans oil before doing this), remove the oil pan, remove the rear most main bearing cap, rotate a new seal into place, replace rear main bearing cap, torque, etc. and reassemble.

Worst case you may have to remove harmonic balancer and front timing chain cover, front seal, release all the connecting rod caps and main bearing caps, remove the crankshaft, replace the rear main seal and reassemble. It's a 1966 engine...you should consider replacing the front timing chain with a roller chain as well as rod and main bearing inserts if you have to do all this.

Remove rear seat. Remove arm rest. Remove side panel. Remove 3 (or 4) nuts that hold the side ornament in place. Hope this helps.

2.8 Ford v6 with ego is shorter and will be powerful enough. Add Ford autobox too

In order to replace the rear main seal you will need some auto repair tools and experience . this is a big job , the transmission must be removed to replace this seal, also make sure that the seal is the leak,

oil always flows down, a leak on the top of the engine will flow down and drip at the center rear and look like a rear main seal , make sure that is the leak!!.

Depending on what engine you have and if it has 4 wheel drive the time for a shop to do is from 7 to 10 hours depending on engine size and 4wd,

Check the vacuum modulator on the drivers side
of trans at rear,the thing with the vacuum hose

Make sure you have vacuum from the engine,
coming from the ported vacuum under carb

It is recommended that you lift out the engine before attempting to replace the oil pan. Once the engine is lifted you can remove the bolts, remove the pan, clean all the old gasket material.
Installation: Remove the rear main bearing cap oil seal Remove the timing cover oil seal Clean all the mating surfaces and seal grooves Install new oil pan front cover seals Install a new rear main bearing cap oil seal Install new oil pan side gaskets on the block Make sure the tabs of the front and rear seal fit properly as these are critical spots Attach the oil pan to the engine block and install the retaining bolts

This is a fun one. You can do this 2 different ways. One of which, remove the transmission and flexplate (automatic trans.) or flywheel (manual trans.) and you can loosen the rear main cap and pull the old rear main seal out and install the new one. The other way of replacing it is removing the engine and replacing the seal on an engine stand. Either way, it'll take some time to do.

You have to drop the pan and inside is a bolt and roll pin that hold the selector rod in. You have to remove it and the rod will slide right out so you can replace the seal.

It is mounted on the passenger side, front fender about 2" inside of the finder edge and about 1" forward of the rear edge of the cowl vent. This photo gives you a good look. http://www.mustangdreams.com/Ford-Mustang-1966.htm To get an exact measurement find a 1964-73 Mustang and measure it.

In order to replace the rear main seal u have to pull the transmission out to access it, u will need a special seal installer tool to install the new rear main "full circle seal", it u don't use the special ford tool the seal will leak again, also if there is a groove worn ion the crankshaft the crank must be repaired or replaced or the or the seal will leak again, so this is avery diff job, a 9 on the scale of 1-10 with 10 being the mos difficult.