Driveshaft shimming

[Parrothead71]

So I'm finally getting my lower unit back together. I ended up replacing the drive shaft with a good used one and the pinion gear as my original one was chipped. I measured from the flange on the shaft to the top of the pinion gear to determine what shims would be needed.
So now after assembly I can feel some vertical play in the shaft and hear the gears "banging" ,for lack of a better turn, when I have pulled up on the shaft.....it goes away after I push back down.
Is this normal or did I not get a good measurement? I am a machinist so I have access to some pretty good measuring equipment.
Oh the engine is a 1976 115hp Evinrude

 

[Faztbullet]

You need driveshaft pinion tool to measure this...take it apart and to a dealer and let them set it up for you

 

[F_R]

So I'm finally getting my lower unit back together. I ended up replacing the drive shaft with a good used one and the pinion gear as my original one was chipped. I measured from the flange on the shaft to the top of the pinion gear to determine what shims would be needed.
So now after assembly I can feel some vertical play in the shaft and hear the gears "banging" ,for lack of a better turn, when I have pulled up on the shaft.....it goes away after I push back down.
Is this normal or did I not get a good measurement? I am a machinist so I have access to some pretty good measuring equipment.
Oh the engine is a 1976 115hp Evinrude

Some vertical play in the shaft is normal, which is the reason for the shims to adjust the amount of play. What confuses me is you say it is noisy when you pull up on the shaft and quiet when you push it down. That is exactly opposite of what would be expected. When you pull the shaft (and gears) away from each other, that is the normal running position because of the gear thrust holding them apart, and they should be quiet. However when you press them together, you are jamming the gear teeth into each other and they will be rough and noisy. But they do not operate in that position.

There is no reason you can't measure and set the shimming without the special tool if you have suitable alternate measuring instruments and know what the specs are. Very few outboard shops have such sophisticated instruments, thus the shimming tool.

EDIT: I would assume your QC department can measure that thing, but even if they can't, set it up along the X axis of your mill, find the two surfaces and read the distance between them on your DRO.

 

[Parrothead71]

Some vertical play in the shaft is normal, which is the reason for the shims to adjust the amount of play. What confuses me is you say it is noisy when you pull up on the shaft and quiet when you push it down. That is exactly opposite of what would be expected. When you pull the shaft (and gears) away from each other, that is the normal running position because of the gear thrust holding them apart, and they should be quiet. However when you press them together, you are jamming the gear teeth into each other and they will be rough and noisy. But they do not operate in that position.

There is no reason you can't measure and set the shimming without the special tool if you have suitable alternate measuring instruments and know what the specs are. Very few outboard shops have such sophisticated instruments, thus the shimming tool.

EDIT: I would assume your QC department can measure that thing, but even if they can't, set it up along the X axis of your mill, find the two surfaces and read the distance between them on your DRO.

Let me clarify the noise part. When I pull up on the shaft pulling the teeth apart there is slop in the gear mesh that you can hear if I twist the shaft back and forth. The noise goes away if I give it a push down meshing the gears fully. I do have a guy that's helped me out some locally I'll probably just have him take a look too.
As far as the special tool goes I found one on eBay that happened to have the dimension stamped on the side, that's how I got those numbers, I then checked it here at work to come up with .01 of shims needed.

 

[F_R]

Well I guess I can't pass judgement on the gears then. It's probably ok, but I'm not there to look and listen.

 

[racerone]

Are you checking this with gearcase fully assembled ?-----Time to use some " mechanics blue "---to check gear mesh / tooth contact.----Pull up on the driveshaft when turning it.

 

[Parrothead71]

Are you checking this with gearcase fully assembled ?-----Time to use some " mechanics blue "---to check gear mesh / tooth contact.----Pull up on the driveshaft when turning it.

Yes it is fully assembled but not full of lube yet.
As much as I hate to pull it all apart again I'm thinking that's what I need to do.

 

[Parrothead71]

I spoke to the shop I got the driveshaft from. Even the ones that they rebuild and use the shim tool on all have .062-.125 inches of up and down play. He thinks what I have is probably ok but I might use the gear marking paint just to be sure.

 

[Parrothead71]

Ok so it's taken me a while to get back to the boat but here is where it sits.
I removed most of the shims and the whine seems to be gone, there is a slight whine still but I think I'm gonna give it a bit to see if the gears just need to wear in.
The problem I seem to have now is that when I go from neutral to forward it goes into gear then I get a hard thump or bang kind of noise. After that it goes just fine.
I cleaned the splines in the crank shaft and the drive shaft as good as I could but could it be the shaft sticking a bit and banging up into the socket in the crank?