I haven't had the work done, but it sounds very high to me. I don't think you have to disturb the gears to change out the clutch pack. I know you don't on an eaton posi because I have disassembled one of those. An experienced mechanic should be able to do the job in less than 2 hours, maybe 1 hr. If you are a shadetree mechanic you should be able to do it yourself.
I just noticed you are from Wilmington NC. I am too when I am home. I am working in Wisconsin right now and my truck is up here with me.
Thanks for the reply. Yeah, I'm from Wilmington, born and raised. I'm pretty good mechanically but every man must know his limitations. I have never worked on a rear end before and I didn't want to start something that I can't finish. I also feel that $500 is steep. I just figured that the Ford dealer has much more expereince with these than someone who has maybe done two of these his/her entire life. Take it easy.
How do you know the clutch pack needs replacement? Is it chattering when you turn? There is a TSB on this and it says replace the clutch pack and reduce the shim preload by 0.010". However, when mine started doing this, I replaced the synthetic fluid and added TWO bottles of friction modifier instead of the recommended one. This fixed it. I have put 18k miles on it since then and it works great.
My truck's rear end feels like something is loose (and makes a noise) whenever I turn left or right. It is more noticable whenever I turn right and has gotten worse the last few months. Between what I read here and other sites, the symptoms sounded like my clutch packs. I took it to the Ford dealer and they diagnosed it. Should I take it to someone else to get a second opinion, of course. But, I figure that has all of the correct tools, parts, and TSB info to do it right. So far, I've had good luck with them.
The clutches in the traction lock are not wanting to turn loose to allow the outside wheel to roll faster than the inside wheel when you turn. This is a typical problem with our model truck. Like I said before, there is a technical service bulletin out on this problem and it says to change out the clutch pack and decrease the shimming by 10 thousandths of an inch. If you want to fix it the cheap way, you change the fluid and add two bottles of friction modifier instead of one. You can do this yourself if you want to. Drain the fluid by removing the rear cover. It doesn't use a gasket. Use RTV for a gasket and reinstall the cover. Then add a qt of 75w140 synthetic lubricant. Add two bottles of modifier and then add about 1 1/2 qts of lubricant to fill it back up. You will not have the problem any more.
By the way, the lubricant costs about $13 to $15 / qt at the dealer depending on whether they are in the mood to give you any discount. You may be able to find it at Walmart under their brand for about $8/qt.
The parts guy at Capital Ford recommended to me to use two bottles of friction modifier. He said that is what most people do. There may be a good reason to do it the TSB way. Maybe I'll have a problem down the road with my diff, but I have put about 18k miles on it since I added the two bottles of modifier and even in the cold of Wisconsin, the clutches are working like they are supposed to without any noise.
Okay, I replaced my fluid in my diff and added friction modifier. This did not fix my chattering problem. I went to a local mechanic who is highly recommended and he wants to replace my rear diff with an Eaton posi unit.
The price difference is about $100 between the Eaton and to replace my clutch packs and casing on my factory diff. Time to start saving my money. Anyway, thanks for your help Roadie.
You did add 2 bottles of friction modifier, right? One won't do it.
In the old days, I had two Chevelles that had the 12 bolt differential with an Eaton posi-traction unit and I liked them a lot. The 65 Chevelle I bought new and put 100k miles on it, much of it 1/4 mile at a time. At about 70k miles, the clutches started popping and snapping in the corners. Changing the fluid fixed the problem. At that time, 1968, the lubricant was sold at the dealer in quart cans and it had the additive already mixed in.
The other one was a 69 SS396 Chevelle that I bought used and kept it for one year. During that time I changed the rear gears from 3.73 to 3.31 myself. I had a time getting the two plates withe the 4 springs back in place between the clutches, until I pressed them together with c-clamps and tied the plates together with fishing line (many loops) and then it was easy to install them and cut the fishing line and pull it out.
In my experience, the Eatons are great. And, the traction lock in my truck has performed well. I don't know why they decide they are too tight after 50k to 70k miles and need shims removed.
I followed your instructions to a "T". It helped a little, especially when turning left. Turning right, however, is just as bad as it was before I started. The rearend also seems more quiet at highway speeds too. My truck has 123K miles on the odo so it's probably time to get them replaced anyway. Thanks again for your help Roadie.
If it were me, and you are going to pay the dealer's price....pay the extra 100 bucks and get that Eaton. If you are going to sell the truck soon, do the cheaper thing. I just had a top-notch diff guy put a new trak-lok posi in my 98 NASCAR for $380 and I bought the Mobile 1. I got to think you could shop for a take-out or new posi unit on ebay or locally and have your diff guy put it in. They should only be charging $100 to$200 to do it. Make sure you get new carrier bearings with the mileage you have. My guy says to do if you have more than 50k on the diff; it's just good insurance.
I am definitely going with the Eaton. My mechanic swears by them and he is no fan of factory LS diff's. I plan on keeping my truck for a long time so to me it's worth the money to have it done right. Thanks guys.
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