SAS trial run problems

[ajevenson]

Have a D44 front with full time hubs and 9" w/trac lok in back. Rear fender height is 42" and front is 40.5" on 33's. New driveshaft 4" diameter lengthened to 51".

THe troubles start when I drive it. it has a serious 'hummmm' to it, sounds like the old school buses but worse. Gets louder with acceleration in all gears, does not decrease when the tranny shifts. As soon as I let off the gas it is quiet. When I travelling 40MPH and let off the gas and then just let my foot touch the gas its twice as loud.

I've set the correct pinion angle, put it 3 degrees up and down just to try and make it sound different, stays constant. I need to rule out some options:

1. do full time hubs make this sound?
2. is a 2" difference in height from front to back causing this?
3. is this the sound that a f**ked 9" might make if the gears/bearings/trac-lok are shot?
4. why me?

 

[CoryL]

Never seen a Ford D44 with "full time hubs" so that the axleshafts turn at all times.

Are the gear sets in the 44 and 9" the same ratio?

Personally it sounds like the gears in the axle are fried.

 

[ajevenson]

Ya, gearsets are the same, 4x4 works like a charm. Here's a pic of the front hub once you pull the metal cap off:

If its anything to do with the rear axle I'm gonna be pretty upset with the guy that sold them to me...

 

[jca]

Sounds like a bad R&P.

 

[CoryL]

Originally posted by ajevenson
If its anything to do with the rear axle I'm gonna be pretty upset with the guy that sold them to me...

Unless it was a friend or a shop, I don't see why.

Just because he "said" things were fine in an axle that is probably at least 15 years old doesn't mean you should take his word for it.

Did you pull the 3rd member and look at the gears before you ran it?

 

[ajevenson]

No I didnt look at any of the internals on either axle. I purchased them because the previous owner runs a driveline shop and the R&P, bearings, trac-lok, etc were supposeldy brand new and just broken in.

 

[Hotweels]

#1 take the front shaft out and test drive it
#2 take the rear shaft out and test drive it (after you put the front shaft back in)
#3 stop by this weekend at a pre arranged time and let me have a look at it.
damn dude so close to being done and you hit a snag that's gotta suck

 

[Dannyboy]

I reinstalled my rear driveshaft with the ujoints lined up opposite of how they should be and had similar noises. I fixed it by making sure the yokes matched up and was good to go. Similar reaction with noise being louder when accel.
Good Luck

 

[ajevenson]

OK finally got a spare moment to pull the rear axle apart. Here's what I found:

Gear fluid was all metal shavings.

Axle shafts are rounded from the tip to 3/4 of the way in. Inside of trac-lok does not appear worn.

Ring has no pattern on the heel and all on the middle-top toe.

Inner axlshaft seal on drivers side is excessively worn in a halfmoon shape on the top only. About 3/16" deep.

I can assume the humming is caused by incorrect mesh patterns. What would cause the shafts and seals to wear so badly?

 

[ajevenson]

Well I think if gots it fingered now, its a write-off. Here's a pic of the problem:

The numbnut that I bought these off of doesnt seem to know his head from his ass when it comes to setting up gears.

 

[Hotweels]

damn that sucks, so the gears and axles are fubared?

 

[ajevenson]

ya i'm gonna go to pyp sometime in the next two weeks and pull two axleshafts. as far as the gears go, the picture doesnt show the heavy stress lines very well on the drive side. i'm not sure if those stress lines will eventually break the teeth off or not. i'm currently 'negotiating' with the seller as to how he is going to remedy this.

 

[Hotweels]

On a side note..... i may be buying a 9" EB diff from a buddy so that will save some grief when SFA time comes along (i hope )