Input shaft moving around a bit, is this normal?

[Florian]

You can move the input shaft of my rebuilt 3.03 around a bit. You can´t move it in or outwards, but you can move it up and down and left and right. Maybe 1/16". Is this normal?

When my old transmission did this after I pulled her I thought this was because of a bad input shaft bearing. But this is a freshly rebuilt transmission from a transmission shop.

Unfortunately uploading the video of it does´t work somehow...

[Racer Z]

For most manual transmissions, this is normal. The shaft nose fits inside the flywheel and crankshaft of the engine to give it the final support.

[Florian]

Ah, now that makes sense! Thanks!

[Nitekruizer]

Just curious. How much should it move? How much is too much?

[Racer Z]

Not really sure. I rebuild one manual transmission (recently) and it had a fair amount of play after I was done. New bearings and synchro's (and seals). All the other parts seemed good. The factory service manual never talked about the end play on the input shaft. The other used trannys we have had the same end play.

My brother and I discussed the situation, we put it in the car and drove it. It seems just fine. We don't have a lot of miles on it yet, but the howl went away (which is why we rebuilt it).

This tranny was a 4-speed out of a Datsun 240z. I expect most others to be similar in concept. The input shaft is supported by the flywheel and one bearing in the trans case. Then there's a secondary shaft (counter shaft) with all the movable gears that slide as you shift gears. There's a third shaft (output shaft) on the same plane as the input shaft. The output and counter shafts are fully supported with bearings. The input shaft has no choice except to flop around because it only has one bearing. It's not fully supported until it's mated to the engine.