1 drive upper, drive gear and driven gear ?

[ziggy]

hi peoples, i've got my drive back together again and have a question. i replaced the drive gear brgs and ft seal and yoke in the upper. my question is? i have just the slightest amount of being able to turn the drive shaft w/o the driven gear being turned. to say it another way. i can feel the the slightest slop between the drive gear and the driven gear..... is that the way it's supposed to be?

 

[achris]

Re: 1 drive upper, drive gear and driven gear ?

The short answer is 'yes', they should be a very slight amount of backlash. Did you set up the shimming using the Merc tools? If you didn't you could find that you will have a noisy top box or you could chew up the gears pretty quickly.

Chris.......

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

Yes, you should have a few thousands backlash between the gears.
No way of actually measuring how much you have other than having the gear heights of both gears at their proper settings.

 

[ziggy]

Re: 1 drive upper, drive gear and driven gear ?

Did you set up the shimming using the Merc tools?

well, i didn't do anything to the driven gear. my goal was to R&R the ft. seal. inadvertantly the drive gear brgs. got R&Red too.... so long story short. i didn't shim the driven gear. i did use the oem drive gear shim tool and it's set to .025" on three teeth. .026" wouldn't go into any three teeth. and .024" went in to easy.... .025" went in stiffly.....

No way of actually measuring how much you have

i scribed a pensil line on a ujoint cap and the retainer nut. i might have the width of a #2 pensil lead line of slop..

sounds like i'm close......was hopeing it was normal and sounds like it might be... guess i'll fill it up with some gear lub....... thankyou.......

 

[rodbolt]

Re: 1 drive upper, drive gear and driven gear ?

gear backlash really cant be ccurately measured on the alpha style units, however 8-14 thousanths is about normal. I usually use some yellow lead gear marking paste to check tooth contact pattern when I am done, its quick,easy and not hard.
the paste is avalible at most any GM dealer.
in a pinch use chalk line chalk mixed with motor oil to form a very thick paste.
gears is gears, we really dont care what its in, same as tapered Roller bearings. all have a physical set of paremeters they can live with.
to tight and they burn,to loose and they get noisy and wear unevenly.tapered roller bearings typically like 8-14 inch`pounds of rolling torque. on the high side for new and the low side for used.
while my shimming tools and my dial indicator are great, they cant beat my eyes and my dial type inch pound torque wrench.

 

[JustJason]

Re: 1 drive upper, drive gear and driven gear ?

can't ya set up a dial indicator on back side of the drive gears teeth, hold the driven gear by hand, and rock the input shaft to get your readings? It's been awhile for me but I though that was how volvo had you do it (aside from the paint) to actually check the backlash. As long as the driven gear doesn't move, and you can keep the tip of the indicator square on the teeth (as in it doesn't slide up or down while checking) you should be ok

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

can't ya set up a dial indicator on back side of the drive gears teeth, hold the driven gear by hand, and rock the input shaft to get your readings?

No, the gears aren't accessable. If you take the top cover off, then you loose the bearing preload and the upper bearing that supports the vertical shaft.
Now how are you going to measure that??????
This ain't no Volvo, It's a Mercruiser. While the industry standard is great in theory, actually measuring backlash in gears accuratly is the problem. you have to figure your distance from the gear, distance from Centerline of the shaft etc. to get that measurement.

 

[JustJason]

Re: 1 drive upper, drive gear and driven gear ?

ahhhhh.... i didn't even think about the preload. silly me too.... Now that i'm actually thinking.. (dangerous i know!) I think step 1 in rebuilding the alpha upper is getting the rolling torque correct on the driveshaft... then setting gear depth on the drive gear.... silly... silly me.

 

[ziggy]

Re: 1 drive upper, drive gear and driven gear ?

I think step 1 in rebuilding the alpha upper is getting the rolling torque correct on the driveshaft

mine is a 1 drive. i didn't set the rolling torque on the driveshaft. i used the old gears(no interferance fit between the brg.s and the drive gear shaft) w/ the small spacer and torqued it down to 85 ft lbs..... the brgs on the shaft turn smooth and freely, but stiffly on the shaft. then i put it together and shimmed the drive gear to .025"

rodbolt. i can understand why i might want to check the gear contact area with some bluein on the likes. ya've commented on this procedure before. i see no mention of it in the service manual. i just read up a bit on backlash and proper gear contact. is this something ya do because yer a tech and know to do this. i don't see how yer doing a rollin torque with it all together again. i assume yer doing the bluein with it all together again too because of the preload from the top cap. where do ya wash the blueing off too. just into the drive. or wipe it clean? tooth by tooth? drive and driven....

i think i have it right. my concern was about the backlash. the fact that i could feel it, which it sounds like ya should be able to do. .006-.014 ya could feel, apperenty there is know way to know. the blueing would confirm my gear contact area though. which i could see as benificial. i'm concered about the clean up afterwards though. but if .025" is right. the contact area must be right. because if it ain't and i need to adj. the depth of the gear to get it right. then i'd loose my .025" and that aint right either..... just thinkin out loud. have a good night folks..........

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

Ziggy, the vertical shaft (driven gear) is the one that has the bearing preload on it, and yes, it needs set first when installing new bearings or gears. Then, you set the gear height, Then you set the gear depth on the drive gear.

As far as gear patterns, if you have the Merc tools, and you set the preloads and gear heights in the proper sequence, there is no need to check contact patterns. They are where they should be. Just by using the special tools.

 

[ziggy]

Re: 1 drive upper, drive gear and driven gear ?

Ziggy, the vertical shaft (driven gear) is the one that has the bearing preload on it, and yes, it needs set first when installing new bearings or gears. Then, you set the gear height,

i didn't do any of that. i don't think i effected that area. only reason it came apart was to R&R the ft. seal and yoke. i didn't take the driven gear and vertical shaft out of the drive. then, i didn't like the drive gear brgs for being blue so they got replaced, so then i felt the need to shim the drive gear since i'd R&Red the brgs. the gears looked ok to me. just slightly shiny at about where i'd want the bluein to rub off at if i was bluein it.....

They are where they should be. Just by using the special tools.

that's the way i understood it.....

 

[starsnstripers]

Re: 1 drive upper, drive gear and driven gear ?

Hey Zig look what i found for ya.

 

[achris]

Re: 1 drive upper, drive gear and driven gear ?

Hey Zig look what i found for ya.

Vindicated!!! Thanks sns,

Chris..........

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

Wrong thread.

 

[starsnstripers]

Re: 1 drive upper, drive gear and driven gear ?

I knew it was the wrong thread Don, I was getting tired and couldn't find it but atleast i had the right guy. I'm learning I'll get it next time Thanks

 

[ziggy]

Re: 1 drive upper, drive gear and driven gear ?

yep, this forum is great..... i sure have a lot to learn. but i'm learning some too.....

sns, looks like ya been readin service manual #6 pp 3C-1....... check out #6 pp 3A32...... alpha drive shaft with a groove, and w/o........ yes achris yer vindicated.... now, should i go take my oring out? yep a retorical question..... next time i'll leave it out...... i 'think' it made it to where it belongs..... least thats my gut feeling........ thanks to all.......

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

I knew it was the wrong thread Don, I was getting tired and couldn't find it but atleast i had the right guy. I'm learning I'll get it next time Thanks

Uhhhhhhhh, Oops!!!!! Dang, I hate when that happens.
What I meant when I posted "Wrong Thread" was I posted a long reply, only to find it on the wrong thread. So I edited it out and wrote "Wrong Thread"
Had nothing to do with your posts, just my mistakes. :redface:

 

[starsnstripers]

Re: 1 drive upper, drive gear and driven gear ?

Oh Well, that makes two of us. **it happens, we wont loose any boating time over it.Thanks Don hava good day. Ziggy, just dont let it happen again! haha! (J.K.)

 

[achris]

Re: 1 drive upper, drive gear and driven gear ?

Uhhhhhhhh, Oops!!!!! Dang, I hate when that happens.
What I meant when I posted "Wrong Thread" was I posted a long reply, only to find it on the wrong thread. So I edited it out and wrote "Wrong Thread"
Had nothing to do with your posts, just my mistakes. :redface:

Don... answer me one question... you got a 'zap' button. Why didn't you just zap it?

Chris............

 

[Don S]

Re: 1 drive upper, drive gear and driven gear ?

Don... answer me one question... you got a 'zap' button. Why didn't you just zap it?

Good question ......................... unfortunatly, no good answer/