rear diff chatter
Thread Starter
|
Professional
Joined: Jan 2005
Posts: 106
Likes: 0
rear diff chatter
05 1500 130,000 miles 5.7 LSD 9.25 axle
i bought this about a month ago, dealer gave me a 3 month 3,000 mile dealer specific drivetrain warranty. i remember when i test drove it i could feel the diff grabbing/chatter randomly when turning from a stop. salesman had mechanic deal with it, he put in mopar diff friction modifier in and it got better, i thought driving it a little more would get rid of all that chatter, i bought the truck knowing i have the warranty in my back pocket.
a week went buy and still had some chatter so i did a fluid change with amsoil 75-140 and added a bottle of the mopar friction modifer. didnt make a difference with the chatter.
today (2 weeks since i changed the fluid) i brought it in to the dealer and of course the mechanic couldnt get it to do it. he proceeded to change the the diff oil. i was told fluid looked clean, no metal but smelled burnt. i didnt tell them i just changed the fluid. he put in mopar synthetic fluid with friction modifier. on my way home it chattered a couple times.
is lsd chatter somewhat normal?
does this chatter hurt anything?
how long do i give the new fluids before i say they didnt fix the chatter and get it back to the dealer?
i bought this about a month ago, dealer gave me a 3 month 3,000 mile dealer specific drivetrain warranty. i remember when i test drove it i could feel the diff grabbing/chatter randomly when turning from a stop. salesman had mechanic deal with it, he put in mopar diff friction modifier in and it got better, i thought driving it a little more would get rid of all that chatter, i bought the truck knowing i have the warranty in my back pocket.
a week went buy and still had some chatter so i did a fluid change with amsoil 75-140 and added a bottle of the mopar friction modifer. didnt make a difference with the chatter.
today (2 weeks since i changed the fluid) i brought it in to the dealer and of course the mechanic couldnt get it to do it. he proceeded to change the the diff oil. i was told fluid looked clean, no metal but smelled burnt. i didnt tell them i just changed the fluid. he put in mopar synthetic fluid with friction modifier. on my way home it chattered a couple times.
is lsd chatter somewhat normal?
does this chatter hurt anything?
how long do i give the new fluids before i say they didnt fix the chatter and get it back to the dealer?
Veteran
Joined: Dec 2012
Posts: 355
Likes: 6
From: Chi - west
I can't imagine the chatter not hurting it.
When I changed mine last time I used Mobil 1 without any modifier. The clatter and click especially on left turns was terrible. Adding 1 bottle of the Mopar stuff stopped it right a way for me.
It don't last forever though.
A reliable source for a lot of Mopar guys sells the Motorcraft stuff................
http://www.doctordiff.com/friction-modifier.html
When I changed mine last time I used Mobil 1 without any modifier. The clatter and click especially on left turns was terrible. Adding 1 bottle of the Mopar stuff stopped it right a way for me.
It don't last forever though.
A reliable source for a lot of Mopar guys sells the Motorcraft stuff................
http://www.doctordiff.com/friction-modifier.html
Thread Starter
|
Professional
Joined: Jan 2005
Posts: 106
Likes: 0
how long should i give the fresh fluid and modifier to see if my issue goes away before calling the dealer again?
i noticed yesterday (day 2) no improvement. has about 50 miles on the new fluids
i noticed yesterday (day 2) no improvement. has about 50 miles on the new fluids
Thread Starter
|
Professional
Joined: Jan 2005
Posts: 106
Likes: 0
Trending Topics
All Star
Joined: Mar 2006
Posts: 833
Likes: 68
From: Chesapeake, VA
I've been through this myself and learned a lot about LSD/anti-spin/posi-trac rear ends.
You need the amount of friction modifier that is appropriate for your clutch pack.
Does friction modifier increase friction or reduce friction (is FM slippery or grabby)? Answer: both. It increases friction during viscous engagement and decreases friction during full engagement. Your rear end is either too grabby during viscous, or not grabby enough during full engagement.
I recommend that you work with dealership on this since you are under warranty. Do not accept that chattering is normal.
What the dealership should do: Change your diff fluid and add half a bottle of FM. Drive it and test it. If it still chatters then add entire bottle. If it still chatters add another half bottle, and so on. Does it get better with more FM? or worse?
At this point you will have done enough troubleshooting to make a case rear end rebuild. I don't think dealer will do the service without troubleshooting and consultation with senior techies.
You need the amount of friction modifier that is appropriate for your clutch pack.
Does friction modifier increase friction or reduce friction (is FM slippery or grabby)? Answer: both. It increases friction during viscous engagement and decreases friction during full engagement. Your rear end is either too grabby during viscous, or not grabby enough during full engagement.
I recommend that you work with dealership on this since you are under warranty. Do not accept that chattering is normal.
What the dealership should do: Change your diff fluid and add half a bottle of FM. Drive it and test it. If it still chatters then add entire bottle. If it still chatters add another half bottle, and so on. Does it get better with more FM? or worse?
At this point you will have done enough troubleshooting to make a case rear end rebuild. I don't think dealer will do the service without troubleshooting and consultation with senior techies.
Rookie
Joined: Jun 2010
Posts: 99
Likes: 0
I think you're absolutely correct. I want to say I used 80/140 conventional. They still share the same GL-5(?) rating if I remember correctly, so I figured it would be ok.
Maybe I'm way off on this, but I have about five thousand miles on new clutch packs, and have no chatter to speak of.
Maybe I'm way off on this, but I have about five thousand miles on new clutch packs, and have no chatter to speak of.
Thread Starter
|
Professional
Joined: Jan 2005
Posts: 106
Likes: 0
05 1500 130,000 miles 5.7 LSD 9.25 axle
i bought this about a month ago, dealer gave me a 3 month 3,000 mile dealer specific drivetrain warranty. i remember when i test drove it i could feel the diff grabbing/chatter randomly when turning from a stop. salesman had mechanic deal with it, he put in mopar diff friction modifier in and it got better, i thought driving it a little more would get rid of all that chatter, i bought the truck knowing i have the warranty in my back pocket.
a week went buy and still had some chatter so i did a fluid change with amsoil 75-140 and added a bottle of the mopar friction modifer. didnt make a difference with the chatter.
today (2 weeks since i changed the fluid) i brought it in to the dealer and of course the mechanic couldnt get it to do it. he proceeded to change the the diff oil. i was told fluid looked clean, no metal but smelled burnt. i didnt tell them i just changed the fluid. he put in mopar synthetic fluid with friction modifier. on my way home it chattered a couple times.
is lsd chatter somewhat normal?
does this chatter hurt anything?
how long do i give the new fluids before i say they didnt fix the chatter and get it back to the dealer?
i bought this about a month ago, dealer gave me a 3 month 3,000 mile dealer specific drivetrain warranty. i remember when i test drove it i could feel the diff grabbing/chatter randomly when turning from a stop. salesman had mechanic deal with it, he put in mopar diff friction modifier in and it got better, i thought driving it a little more would get rid of all that chatter, i bought the truck knowing i have the warranty in my back pocket.
a week went buy and still had some chatter so i did a fluid change with amsoil 75-140 and added a bottle of the mopar friction modifer. didnt make a difference with the chatter.
today (2 weeks since i changed the fluid) i brought it in to the dealer and of course the mechanic couldnt get it to do it. he proceeded to change the the diff oil. i was told fluid looked clean, no metal but smelled burnt. i didnt tell them i just changed the fluid. he put in mopar synthetic fluid with friction modifier. on my way home it chattered a couple times.
is lsd chatter somewhat normal?
does this chatter hurt anything?
how long do i give the new fluids before i say they didnt fix the chatter and get it back to the dealer?
update
brought it back to the dealer cause im still getting chatter along with a mild howl starting at 60mph. mechanic heard the howl and they are gonna do diff bearings and clutch pack under warranty. gonna cost me deductible, $100.