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Michael J Hawk
07-06-2014, 09:50 PM
Recently purchased a '61 Hawk with flightomatic. It works ok but leaks everywhere. I have a good th350 I could swap it for but I would like to keep it in there since the rest of car is all stock. I've rebuilt trannys before so don't mind the task and the parts seem reasonable. Are shift points and drivability improved with the GM transmission?

JoeHall
07-06-2014, 10:01 PM
The TH350 is a 1st gear start, 3-speed. The Stude Flight-O-Matic is a 2nd gear start, 3-speed. A conversion kit to install the 350 behind the Stude V8 costs around $400 total, and you'd need another drive shaft, and a few other odds and ends.

Oops, I'm not an "old timer" though :D

Michael J Hawk
07-06-2014, 10:47 PM
Thanks. I didn't realize it didn't start in 1st gear. I only drove it once and then parked it to do the brakes. They're completely shot. So while crawling around under there I see a puddle of oil under the transmission. It was motor oil. The engine looks clean and rebuilt. Can the real main seal be replaced on a 289 while the transmission is out?

sals54
07-07-2014, 02:23 AM
Thanks. I didn't realize it didn't start in 1st gear. I only drove it once and then parked it to do the brakes. They're completely shot. So while crawling around under there I see a puddle of oil under the transmission. It was motor oil. The engine looks clean and rebuilt. Can the real main seal be replaced on a 289 while the transmission is out?

Its just my thoughts, since I don't have to do the work, butů now would be a good time to just pull the engine and do a full gasket replacement. Especially the oil pan and rear seal. While you have it out, do the freeze plugs, too.
Like I said, its not my labor, but you could do a lot of good for it over the course of a single weekend.

gordr
07-07-2014, 10:23 AM
What Sal said. IMHO, swapping in a TH350 for the Flightomatic is not worth the effort. Gas mileage will be no better, since both are 1:1 on the top end. Acceleration from a standing start may be a little better, but first-gear start is already there if you drop the selector into low, and then shift it manually drive once you reach about 25 mph. Swapping in a 700R4 or 2004R tranny will get you an overdrive, which adds better gas mileage to the mix. I, for one, wouldn't do the swap for the first-gear start alone; just not worth it to me.

sweetolbob
07-07-2014, 10:31 AM
What Sal said. IMHO, swapping in a TH350 for the Flightomatic is not worth the effort. Gas mileage will be no better, since both are 1:1 on the top end. Acceleration from a standing start may be a little better, but first-gear start is already there if you drop the selector into low, and then shift it manually drive once you reach about 25 mph. Swapping in a 700R4 or 2004R tranny will get you an overdrive, which adds better gas mileage to the mix. I, for one, wouldn't do the swap for the first-gear start alone; just not worth it to me.

What Gord said, If you can reseal the existing tranny/engine go with that otherwise do one with overdrive.

StudeRich
07-07-2014, 12:27 PM
Thanks. /Cut/So while crawling around under there I see a puddle of oil under the transmission. It was motor oil. The engine looks clean and rebuilt. Can the real main seal be replaced on a 289 while the transmission is out?

To answer your question, Yes you can do it while the Engine is in, but the Trans. does not HAVE to come out, it just makes it more difficult.
However you can do a much better job on the Rear Main Seal and a LOT easier with the Engine out.
The Timing Cover Gasket and Seal, the Pan Gasket and the Main Seal are really best done all at once since they are inter connected.

Also you need to get a better look at the rear of the Oil Pan to determine if the leak is just coming from the Pan Rear Arch Gasket or the Main Seal on the Crank.

Michael J Hawk
07-12-2014, 09:52 PM
Think I'll just rebuild the old F.O.M and try to fix the rear main while its out. Looks like the engine was rebuilt at one time but maybe didn't pay enough attention to the crank condition. Thanks everyone for the advise.

sals54
07-13-2014, 01:28 AM
The rear mains on these engines are notorious for leaks. Even when rebuilt. It takes some special care to do the rear seal correctly. Some shops will slap them together and hope for the best. A few drops of permatex in the right places will seal it for the life of the rebuild.

Studerick64
07-13-2014, 09:48 AM
Rear pan gasket can dry and shrink. Drop the starter and starter plate, clean the area with brake cleaner then pack some RTV or gasket in a can in there and let it set up. Once it sets up reassemble. This is easy and if it doesnt stop the leak then its time for a new rear seal and gasket set.