HELICAL GEAR.

M274 Mechanical Mule Knowledge Base
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Guam0311
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HELICAL GEAR.

Post by Guam0311 » Tue Nov 27, 2018 12:03 am

When I removed the left rear drop gear housing and axle assembly to get to the seal mentioned on another thread topic, I drained the oil out and to my surprise and dollar signs, falling out was metal shavings and sheared shaft splined pieces.

I would guess the splined sheared pieces came from the CV joint inboard shaft. What would cause that?

As for the helical gear, manual listed as: "helical gear wheel joint driven". PN: 7966765. When I lifted off the gear, I found the bottom bearings and cage grenaded. Lack of oil? severe duty?

So now I am in the search for a CV Joint and the gear and both caged bearings.
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Chuck W.
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Re: HELICAL GEAR.

Post by Chuck W. » Tue Nov 27, 2018 9:13 am

Have you checked the 5208 bearing? I would take a close look at the cover housing and make sure nothing is bent/cracked.
I would also check the inner axle ball bearing, it is the one that usually fails. Charles has a good post on here somewhere describing how to remove the snap ring that retains the bearing/axle in the housing.
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muleman7
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Re: HELICAL GEAR.

Post by muleman7 » Tue Nov 27, 2018 4:02 pm

Did not find the Post after a short search so here are the pics

Top Axle is held in with a spring clip

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Use needle nose pliers to remove clip from groove.

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Once removed use a knee bar or small flat pry bar to pull axle assy from DG housing. I suggest checking the 205 bearing behind the axle gear and replace if worn. Most bearings come with shields and these should be removed and the bearing packed with grease.

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Pressing off the gear and bearing.

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Tools used.

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Removing the B1412 needle bearing. REMEMBER when installing the new needle bearing set it deep enough to keep the lube passage feeding the top gear and bearing open

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Tools used.

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Guam0311
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Re: HELICAL GEAR.

Post by Guam0311 » Sat Dec 01, 2018 12:21 am

Chuck W. wrote:
Tue Nov 27, 2018 9:13 am
Have you checked the 5208 bearing? I would take a close look at the cover housing and make sure nothing is bent/cracked.
I would also check the inner axle ball bearing, it is the one that usually fails. Charles has a good post on here somewhere describing how to remove the snap ring that retains the bearing/axle in the housing.
After cleaning the surface area real good, I did a detailed inspection and the cover seems ok, as well as that 5208 bearing. I think I have a new 5208 bearing so I may change it anyway.

The middle needle bearing that supports the idler gear with the Bronze thrust washers is damaged and Does not appear to be set deep enough or worked its way out. (not sure how that would happen?) The bearing is actually above the surface just enough that it machined in a deep groove in the thrust washer. You can see in the picture the crack on the bearing cage
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Last edited by Guam0311 on Sat Dec 01, 2018 12:38 am, edited 1 time in total.

Guam0311
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Re: HELICAL GEAR.

Post by Guam0311 » Sat Dec 01, 2018 12:32 am

Thanks Charles and Chuck for the Technical help, and tooling recommendations.


muleman7
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Re: HELICAL GEAR.

Post by muleman7 » Sat Dec 01, 2018 10:36 am

From your pic the needle bearing case appears to have the rounded edge out. This side of the bearing should be inserted first with the square shoulder out. I do not see a way that the bearing could work out if the fit is within specs. The bearing does not come out easily even with a blind hole puller and a slid hammer.

With the damage indicated in your post I would replace 3ea B1412, Axle 205 and Hub 5208 bearings plus the copper thrust washers on the idler gear. I did not include the driven gear and bearings/cups because you mentioned replacing them.

Caution: After replacing the driven gear and bearings/cups check the preload.

I check the preload by assembling only the driven gear and 4 nuts around the gear for the gear cover. Tap the gear cover at the dowel pins and tighten the nuts. If it is the rear and 2 ws use the axle to turn the driven gear to feel the preload. If 4 ws you can use your finger or the CV joint.

The manual specifies a 0.001-0.003 end play using a dial indicator. To adjust you must remove the cup from the steering gear cover and add or subtract shims.

I set the driven gear so there is a very slight drag [pre-load]. I do not want this gear to wobble due to the 0.001-0.003 end play. Plus not everyone has a dial indicator. All other tapered bearings: F/R pinion [3-5 lbs pull on a spring scale] and F/R ring gear cage [5-15 lb in to turn] bearings, all are preloaded. You can use a spring scale on the axle or CV joint to check preload by wrapping twine around the axle/CV joint.

The driven gear is bathed in lube and the heat generated has to be less then the front end pinion and ring gear bearings produce.

According to LO 9-2320-246-12 28 Jun 1968 lub to fill is 6oz for the front end and 12oz for the DG housing assy.

Just a thought I welcome other opinions-suggestions.
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tga
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Re: HELICAL GEAR.

Post by tga » Fri Dec 07, 2018 7:20 am

We have the parts you are looking for, if you're still needing them. arvintga(at)gmail(dot).com Trent

Guam0311
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Re: HELICAL GEAR.

Post by Guam0311 » Sat Dec 08, 2018 10:33 am

tga wrote:
Fri Dec 07, 2018 7:20 am
We have the parts you are looking for, if you're still needing them. arvintga(at)gmail(dot).com Trent
I contacted John Emery, he has the CV joint I need. I may need some parts in the near future so thank you TGA.

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