Chatter/Vibration from Rear Axle with Trak Lok while in a turn

[Metalhead]

I'm pretty sure I've narrowed down the vibration and chatter I've been feeling to my rear axle, with the trak lok posi. I've got another thread on here where I was asking about how a slipping tranny felt. The more I've been feeling this, the less I think it's tranny, since take-off, shift and power all feels the same.

I went to the walmart parking lot today to test out the symptoms, and it only happens when I back slowly when in a slight turn, same thing for pulling forward. It even happens when I'm rolling in neutral, while turning slowly. It never happens when moving straight. I came home, raised the left rear wheel off the ground and put the truck in N and engine off, and I can feel a good stick to the wheel when trying to turn it, with it eventually turning after I put enough force on it.

I've checked the fluid level in the rear axle, and it's right up to the check plug.

This chatter/vibration has been happening ever since two weeks ago, when I tried driving up a steep dirt hill in 2wd, spinning the right-rear well pretty good for about 3-4 seconds, before I kicked in 4x4.

Does the fluid go bad after awhile, causing this chatter? Or is this telling me I've got worn out clutches in the trak lok? Would a fresh fluid change fix this instead? I've almost had the truck for 30,000 miles now... Not sure if it was ever changed before...

 

[Zmann ARGH]

ok you had the truck for 30k but what is the mileage total .. there is an additive if you have the limited slip

 

[Metalhead]

99700 miles now total

 

[JLDickmon]

you need to change the diff fluid...
and don't forget the limited slip additive.

 

[Zmann ARGH]

it's a special oil also ford or mobil are the only I have found and it's synthetic .. look at your diff for the viscosity

 

[Smoky]

If you don't have enough of the friction additive in the rear then the clutch or whatever it is in the rear will chatter but too much will cause it too slip too much. Be sure of how much of the additive you put in the rear. Some of the fluids have the friction modifier additive already premixed in the fluid.

 

[powerboatr]

you need to change the diff fluid...
and don't forget the limited slip additive.

x2

sounds like the friction modifier is .... well un modifying any more. it will give you all kinds of clinks clatter and chatter, 100k on the oil is in need of changing.

 

[Bowhuntwi1]

I have an F350 CC 4x4 SRW 6.0 Diesel KR with your same problem, but I'm going on a 150,000 miles and each time they ( Ford ) told me my problem was my clutches, well I bought mine in July of 05, they being Ford replaced them under Warranty in Jan of 06 and Mar of 09, I paid for them in Jan 2010 and now I have the same problem today in Feb of 2011. I talked to a Ford Mechanic and he advised me that the shims keep a set amount of pressure on the clutch packs to aid in applying the limited slip. By being set too much the limited slip works more often under the set amount of pressure in a loss of traction. By loosening the pressure, the limited slip is not used under small slip conditions as much. When towing the rear end is under more strain and can cause the limit slip to prematurely wear out if the shims are too tight. He suggested measuring the current shims and then go .005" less. I called Ford and plead my case but they said with the miles, I'm on my own. I talked to my dealer and he's cutting me a couple of hundred off this repair and said he would talk to the Ford Rep about going the .005" less. I have searched and searched the web for others with this problem and finding things are like looking for a needle in a haystack, but I see we have the same model and year with the same problem, but you would think you could fix it once and not have a recurring problem, I tow probably 60% of the time but nothing over 7000 and that's nothing for a F350 diesel. CHanging the fluid and adding modifier was also brought up but they also said it wouldn't solve the problem.

 

[Zmann ARGH]

i would dump a container of modifier in yours first .. plus the clutches can be done in the driveway in a few hours for under 200