transmission input shaft normally loose, 1994 B2300?

kp3ft · Jul 9, 2010

Just removed the manual transmission for my 1994 Mazda B2300. I noticed that the input shaft is is slightly wobbly in it's bearing... is this normal or is it supposed to be firm in the bearing? Also, does the bearing for the shaft need to be packed with grease, or is that a bad idea? It looks like the transmission oil is supposed to flow through the bearing instead, but my knowledge is very limited with manual transmissions.

kdowney50 · Jul 10, 2010

You have a problem

The input shaft should be firm. If it wobbles, the support bearing is most likely worn. You will need to have it replaced. Do NOT ignore this. The worn bearing can damage the transmission and the engine rear seal.

The transmission fluid should lubricate the bearing so it won't need grease. FYI: the manufacturer recommends using Mercon Automatic Transmission Fluid. NOT Mercon IV. And not 80W-90 gear oil either! (Which I have put in every other transmission I worked on.) There are nylon synchronizers and seals that will be damaged by regular gear oil. Your tranny should hold about 2.5 qts.

BTW: what did you do about the slave cylinder hose?

Mirage · Jul 10, 2010

I have to agree. A few years ago I lost 2nd gear (actually I was stuck in second and couldn't get out), and pulled my trans to rebuild it. I found the same thing, a sloppy input shaft. I thought it strange too. No it should be firm. And it will lubricate itself, although as I was rebuilding it I pre-lubed everything as it went together with a little Mercon ATF.

Are you going to rebuild this tranny yourself? If so I know a a place to get parts that is friendly experienced and extremely helpful. I don't want to sound like a shameless plug for these guys, but check out

southwestgear.com

They really helped me out when I needed it.

Good luck!

kp3ft · Jul 21, 2010

Thanks for the reply. It's firm now; the problem was a spacer shim was missing. Regarding the slave cylinder hose, I ended up replacing the slave cylinder ($50) because the Mickey Mouse, dumb-engineering-decision "new and improved" hydraulic fitting was bad. They put the same type fittings on the power steering. So far I've spent about $100 dollars due to these moronic fittings, both on my 94 Mazda pickup and our 89 Ford Crown Victoria. The old style was the tried-and-true compression fittings that can only fail if they are cut, hit with a hammer, or rusted through. The new fittings can pop out with too much pressure (happened to my wife's car), and the only thing preventing them from leaking is literally a tiny rubber o-ring. Both vehicles are for sale, and I am going to get an older pickup for myself and an older car for my wife... I am through with stupid engineering practices, an overload of microprocessor and sensor control, and fuel injection, and tree-hugger EPA control freaks regulating newer vehicles. When people proudly show me their new shiny vehicles, I feel sorry for them; I only see a lot of dollar signs, headache, and regulations.

kdowney50 said:
The input shaft should be firm. If it wobbles, the support bearing is most likely worn. You will need to have it replaced. Do NOT ignore this. The worn bearing can damage the transmission and the engine rear seal.

The transmission fluid should lubricate the bearing so it won't need grease. FYI: the manufacturer recommends using Mercon Automatic Transmission Fluid. NOT Mercon IV. And not 80W-90 gear oil either! (Which I have put in every other transmission I worked on.) There are nylon synchronizers and seals that will be damaged by regular gear oil. Your tranny should hold about 2.5 qts.

BTW: what did you do about the slave cylinder hose?

transmission input shaft normally loose, 1994 B2300?

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