MTFCA Forum

I'm working on a tranny for a friend who doesn't want to put any more money into it than he has to. The engine/trans will go into a truck which will be driven very little. He says that he went into the engine and it "looks good." The reason I'm working on it is that it has a cracked brake drum. My friend found a useable brake drum and asked me to swap them out for him. When disassembling the tranny, I noticed that the triple gears were turning independently from their bushings. Two of the bushings turn on the pins, but one is frozen to its pin. The clearances don't seem bad (except for the gear-to-bushing, obviously); in other words they're not sloppy. I'm wondering whether it really makes any difference whether the bushing turns with the gear or stays with the pin. It would save my buddy some $$ if I just put it all back together and run it the way it is (but with a different brake drum). Thoughts?

Fix it the right way.

Given the parameters of $$, I would remove the bushings, press them to expand the O.D., press fit back into the gears,(making sure the shoulder height spec. is maintained. If short, shim back under the flange.), using some locktite bearing mount adhesive. Re-bore the holes to .004" minimum clearance.

You can buy 1 economy bushing from Lang's for $20, (or best quality @ $29.00). I'd install that to replace the seized one and bore it to the same clearance as the other 2.

In the real world, what difference does it make whether the bushing turns on the pin or the gear turns on the bushing? It seems to me that both situations accomplish the same thing.

The inside diameter of the gear is not meant to be a bearing surface. They usually appear to be rough broached. On the other hand, the bushing spinning on a hardened and ground pin will last far longer.

Check and replace the pins. If you get them from any vendor polish them or you will be back where you are now in about 100 miles or less. Also they may not have the shoulder on the magnet side so be sure they fit the hole in flywheel correct.
Use only the best bushings and ball size them or you will be replacing the gears.
Fix it right or fix it again.

Mike,

I am a firm believer that whether intended or not...a proper set triple assembly works as a miniature oil pump, 'walking' oil along the pin surface. Sure, you won't find it written anywhere...but there is absolutely no other technical explanation for why the facing dimension after bush insert is known to be critical, why Ford specifically called out the radius and edge of the grooving tool, and why the Ford oil groove helix was actually 'off center' and to a specific spiral angle and why if folks try less than about 0.0035 clearance they get about 150 miles out of the tranny before something seizes. Sure, it all flies in the face of modern design, and modern understanding of lubrication...but the artistic approach let 15 million of them have a decent life!

FWIW When the late Ralph Ricks and I did the blind forensic testing of over 100 sets of used pins and bushings a while back we did find more than a few that had 'spun' on a stuck pin to bush ID and appear to have been run that way for a long time, yet the OD of the bush wasn't pretty at all and had grooves where it had tried to grab from time to time. Not good.

Mike I think the bushing should be replaced. The inside of the triple gear is not designed to be a bearing. The material and finish are not right to use as a bearing. If you can remove the seized bushing without damage to the pin or loosening the pin in the flywheel. I will send you a box of nice triple gears to pick from. I can get several triple gears in a small flat rate box. I know who you are building the engine for. He can return what's left next time we see each other.

Fix it. Something similar happened to my transmission. I had gears spinning on bushings and bushings seized to pins so the pins spun - eventually right out of the flywheel. It happened over time, maybe a few years, but the end result was not pretty. You need to be very careful to get the clearances right so that the bushings spin freely on the pins.

Look into ball sizing bushings.

Tim J. It looks to me that you need an other flywheel !!!
Toon

Per Dan's recommendations and with his instruction I ball sized my triple-gear bushings prior to placement on the pins. So far after 1 tour, they seem fine. I believe this procedure work hardens the inner bushing surface as well as forces the bushing to fit tighter into the gear. It is also easy to do for those lacking a lathe. It requires a hydraulic press, however. Thank you, Dan Hatch!

Thank you everyone for your suggestions.

The bushing spinning in the gear, use a punch to knurl the outside of the bushing then press it back in with a bit of bearing and sleeve retainer.
Just make sure the inside is still ok for running on the pin.