3 spd saginaw issues racing in high gear?

[rick7343]

Running 1/4 mile oval track and while in hight gear , the gears all seized on the output shaft and the trannie seized up and destroyed itself... almost putting me in the wall...

SO is this a problem caused by the lubricant being flung off since we run 4-6500 rpm? Or just a poor lube?

These gears don't appear to have any bearings, so how long can they run at high speeds?

I thought it was common to run these standard trannies in high gear.... Would it matter what gear it was in, the gears all turn different speeds anyway since they are all driven by the countershaft... (?)

thanx rick...

[PackardV8]

Never had a 3-speed manual fail like that. What lubricant were you using?

jack vines

[Barbapapa]

Even though it's in direct high gear, the countershaft has fixed gears that are turning at speed all the time so if any of the gears siezed on the mainshaft it would be a big problem.

I ruined a couple of Saginaws in my youth that didn't seem to be breakage but more like things getting stuck or something, hmm...

[rick7343]

I was trying to run thinner fluid for less friction loss... ATF with lucas... I heard modern trannies run ATF... maybe they have needle bearings.. Probably won't do that again...

Just wondered if it was a common prob...

[autogear]

Im not a Saginaw specialist; but I do know theres a place (Magnus Racing Products in CT) that does roller bearing conversions under the mainshaft gears to keep this from happening. I'd say improper lube or not enough of it is the odds on favorite however, the saginaw was never designed to be pushed the way guys are these days and with the lack of quality new parts available, failures can be common. Contact Mike over at Magnus and see what he can do for you. Glad you're all in one piece.

[PackardV8]

I heard modern trannies run ATF

Yes, but the Saginaw is a 1960s stone age design. AFAIK, it may have been the last 3-speed tranny ever designed.

jack vines

[barnym17]

Your lube killed it, it needs 85/140 or 90 wt.,modern trannys get away with atf due to tighter clearances and different bearing styles.Ran many of them at 7500 to 8500 rpm no problems.Altho they have been replaced by direct drive traanys now such as bert and brin or falcon.

[crazyman]

I had a saginaw 3spd lock up going about 30mph. The hurst was worn out and both selectors on the trans were engaged. I shut the car off and got under it. Snapped a selector back and the car started rolling down the hill. I narrowly avoided getting my arm smashed by the tire.

[rick7343]

Do newer trannies have some sort of pump?

It kinda makes sense that mainshaft gears would starve for oil since all the gears act as flingers and would be throwing oil off the shaft..

To make it worse, this was an old rebuild and it seemed aweful dry inside... Maybe if they never lubed it , it never saw lube.. It's all above the oil line..

[barnym17]

When the oil level is correct the gears themselves act as a pump of sorts slinging oil every where.

[autogear]

The new crop of 6 speeds has a pump and some race boxes have pumps; but you need to understand a factory 3 or 4 speed is usually pretty good at keeping itself oiled. When you pile more parts in the box (multi part synchro rings etc) You cut down on its efficiency. You need a GL4 or GL5/MT1 oil in the 75w90 to straight 90 range. Two I recommend are StaLube from Napa (its through CRC) in a 1qt bottle. Non synthetic. Napa PN SL24229

Occasionally I recommend Royal Purple's MAX GEAR (only the max gear) in a 75w90 or there abouts.

[CanadianRacer]

I build allot of Saginaws for circle track and we race them in our sportsman car. 530 HP turning 7800 rpm. No problems to speak. Here"s the secret GL4 oil, not ATF. I use Amsoil Manual Transmission & Transaxle Gear Lube 75W-90. never had any issues yet. Make sure you start off with a rebuild kit in it. These trans are all over 30 years old now. Buy a kit or bring it to a reputable builder. The Saginaw three speed has the lightest rotating assembly out there, thats why they are quick!!!!