Rear differential

[Mark Price 2]

Oh no! I had my entire rear diff rebuilt back in Dec.2012. I was planning on changing the gear oil after "break in" at some point. I asked when it was done if I needed to do that and the guy said just leave it be. So I never got around to it until today. Well, Ive been periodically checking the fill magnet. ..The last 2 times in a few month period, I found CHIPS! not tiny shavings. ST sounds fine.

I decided to go ahead and change it today. I found that there were chipped teeth on 2 of the spider gears. The 2 that the large pin goes through. At least 2 chipped in each of those.

Questions: The 2 spider gears that the pin runs though-Are they supposed to be able to move? The other 2 are tight. They have a little play. Like maybe 2mm. Up and down the pin that is. not in-between the teeth.

Also, when in park. Is it ok that the flange rotates like 1/2 an inch back and forth? (backlash) The flange is nice and tight.(no loose play in/out up/down) But I can rotate the drive shaft back and forth a bit. I can hear a slight quick clunk when cruising 40mph and "juice" the pedal.(all windows up except rear) Easy acceleration it doesn't cluck. Never noticed before as I never "juiced" it before. As in, it clunks once as it re-engages I guess.

Do you think I'm ok? Since there is no whining happening.

Here the bigger problem. My warranty was 12mo/12,000. Well I just turned 12,100/9 mo. since rebuild. OOPS!!! I think the /slash is an "or". If I find some time I will go back and hope they are ok with that. I did spent 3500 at this trans shop last year. $1500diff and $1800 rebuilt trans for a Honda. Also, I noticed they didn't put the drive shaft on were it was originally. The yellow factory marks on the drive shaft and flange are opposite of each other now. Geez. No ill effects though.

Thanks for any input

These are all the chips Ive collected. 1 chip each of the 2 times I checked the fill plug and the rest I found with a magnet in the drained oil and in the housing.



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Not the best pics. Sorry. I put the trans in neutral and spun the spider gears around with the tire. Nice and smooth, easy to turn. Except, it got to one point where there was a slight resistance for maybe 10 degrees(in the spider gears). IDK if that's ok either?

pics 1 and 2 are of the same tooth. Looks worse in the pic than it is.

 

[Mark Price 2]

This is basically what I am seeing (not my video) Except I seem to recall mine were sliding a bit up/down the pin. Not really that much play in-between the teeth.

 

[Mark Price 2]

my "backlash" is about half the amount shown on the video (again,not my video)

 

[Mark Price 2]

like this! ..i have 4.10 conventional - open (non LS)

 

[Todd Z]

SAME thing happened to mine, I replaced the whole thing with new gears and a cobra posi from motorsport..



Todd Z

 

[Vic Sorlie]

I think this differential is going to fail sooner or later. On the rebuild I recommend an aftermarket cover (such as Mag-Hytec) that makes fluid changes a snap as well as increasing fluid capacity. That, and using the best gear available - AMSOIL Severe Gear.

 

[Yardsale]

All parts fail sooner or later.



Try your drive line rotation test with the transmission in neutral (you don't want the transmission limiting the drive line movement).

 

[Mark Price 2]

Good point Yardsale. I thought of that after I posted. Seems ok? we'll see...

I understand "sooner or later" But, not this soon. 9 months on a fully rebuilt Ford 8.8. (Plus, I drive like a grandpa.)