Simpleaim

So after trying to read everything I can and after the many response regarding my rotational rear end sound, https://www.f150forum.com/f4/rear-en...-sound-295444/, I think I'm going to replace my pinion bearing.

It's very confusing as to what to order. The only sites I've visited are Randy's and there's a variety of things to order. Should I also replace the carriers? Do I need shims? I'm at a loss as to what to get.

Also should I replace the clutch packs while I've got it apart? It wouldn't be a big deal to wait but with the gear oil and modifier being almost $100, I'm leaning towards just doing it. By the way, I'm doing this myself.

Anything else I should do while I've got the diff open? I'm the kind of guy that would rather do it while I'm at it.

Thank you,

Ken

VTX1800N1

This is what I'm going to do with mine when I get the funds:

Differential seal and bearing rebuild kit. You might as well do all of it while you have it torn apart, because the cost of labor is sure to come back and bite you if you don't:

http://www.drivetrainamerica.com/p-1...1999-2006.aspx

Detroit TrueTrac differential. This is MUCH better than the stock clutch limited slip, will never wear out, and considering the parts and labor cost of rebuilding the stock unit this is a much better choice for not much more money:

http://www.drivetrainamerica.com/p-3...-975-f150.aspx

You will need 2 of each of these (not included in the master kit above) if you have not replaced the wheel bearings. Again, you may as well get it all done at once:

http://www.drivetrainamerica.com/p-2...l-bearing.aspx

http://www.drivetrainamerica.com/p-5...axle-seal.aspx

I'm also going to have the shop eliminate the crush washer with this. Again, minimal cost:

http://www.drivetrainamerica.com/p-2...010-older.aspx

Total cost for parts and labor is going to be about $1500. The good news for me is that I'm dumping the open rear differential, so I will have a much more capable winter truck when I'm done.

Simpleaim

Thank you. I'm doing the labor myself. Have you talked to them? The diff rebuild kit is out of stock right now. The Detroit Tru Trac is an interesting replacement. I'm trying to keep this repair below $500. I just dumped $1500 into my tuck replacing cam phasers, timing set, followers, lifters, oil pump, screen and all of the gaskets, additional tools and everything else.

Thank you,

Ken

VTX1800N1

They have a lot of inventory turn over. It will be back in stock again soon. I wish I had the confidence to set up the rear end myself, but I'm going to have to pay the local Ford dealer ~$600 for this work. That's a bargain, IMO. Parts totals are ~$900.

PerryB

Is that a 9.75" axle? I just had mine re-clutched a couple months ago because it was getting noisy during tight low speed turns, made a "whoop-whoop-whoop" sound. I took it to a local trans./axle shop where I've known the owner for about 25 yrs. (meaning I trust him) and was told that noisy clutches are fairly common in that axle.
With regard to that hideously expensive oil, I I took 3 quarts (yep, $100 same as you) to the shop with me, and the owner said he'd prefer not to use it. He said his experience has been poor with synthetic oil in limited slip applications, and has had several cases of squawking or chattering clutches as a result. He doesn't like the stuff unless its required in extreme duty/high perf. applications which this is not. It was hard to go against the book and use a different fluid (regular old 80/90 GL5) but I trust this guy so I went with his recommendation. So far i have a smooth quiet axle.

jamie930

Ford LSD need the Motorcraft friction modifier no matter what oil you use in the diff

PerryB

That is absolutely correct regarding the friction modifier. If you leave it out you WILL have a squawking and chattering rear diff.

Simpleaim

It is the 9.75. So you had your clutches redone but just used the original spec oil? I have a tag on my diff that says to use the 75W140. I did buy this 04 used with 35K miles on it so the original owner must have had it changed. I should note that I replace the rear axle bearings and seals about 2K ago with the 75W140 and friction modifier. All MC.

Thanks,

Ken

Simpleaim

They've got a good price on the bearings. Nobody else can get close to that price.

Thank you,

Ken

PerryB

At the advise of the shop owner we put standard 90 wt. GL5 in the diff, along with slip lube (friction modifier). My axle also calls for 75/140 synthetic. My bearings were perfect. All I needed was clutches.