Loud Clunking Noise

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RichardJ916

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Over the past few months if not more, some days it seems worse and some times not at all I have been hearing and feeling this loud clunking noise when turning a corner or backing out of the driveway coming for the rear end. It feels like the wheels are grabing and then a clunk, kinda like the brakes are grabing. Its a pretty new Mancini Racing Centersection MRE875489 ( Mopar 489 Rearend 8 3/4 " ) 355 gear. The noise is worce when making a turn at very very low speeds, it has never made the noise from a dead stop going straight. If I roll into a turn it doesnt make that noise, but right or left turns from a stop it does. I have looked at the ujoints and all seem to be fine....
Heres another trouble, last year when i put the new motor in I needed help to turn the weels to get the drive shaft in when mounting the ujoints... meaning it took a lot of force to turn the wheels to get the ujoint to line up. You cant spin the wheels when up on jack stands like the free rolling front ones, it takes a lot of force to turn the wheels... if that makes sence. i dont have a problem removing the Centersection but just wanted to pass a few things through you guys first.....

Any thoughts ????
 
Did you add the friction modifier when filling the rear lube?? Does it have Green bearings or the OE style tapered bearings? Preload on the rear bearings set correctly? Brakes adjusted alright? Just a few suggestions here!!!...
 
A little history on Duster:
I got the car about 4 years ago. The man I got the car from gave me a list of parts he had replace. The paper work I got from him said replaced from Mancini's Racing Inc. was a MRE-875489 ( 2006 for the price of $950.00 ) if you look up the number it was for the complete centersection Mancini 489 8 3/4 355 gear... todays new price is $1395.00 ( Wow ). Over the last few yrs it has been fine but i did notice it making a few weird noises last year. The breaks are new as well last year when i put the new 360 motor in. The Axels are Yukon which are new also. I am now sure on Green Bearing seeing there is no sheet telling me what he installed I could ask him but was unable to talk to him last night. I have never checked the lube, I should have when I put everthing back together last yr but didnt. What is hard to understand is the tightness of the rear end when both wheels are off the ground and no drive shaft installed It is very hard to turn the tires weird feeling. It doesnt make the noise all the time, it seems the tighter the turn the more it clunks..... IT doesnt do it all the time and never going straight. I can add the sure grip stuff but wanted to talk more about it also.
 
This is isn't (only) additive related.
The wheels should turn almost freely when they're both off the ground.

I would take it all apart and inspect all the bearings and preloads. Something is binding up it seems.
 
When you say the noise is more pronounced on cornering I would suggest you take a look at the spider gears in the differential. When moving straight ahead the whole diff carrier is turning as one unit, but on cornering, because the inner wheel has a smaller effective turning radius as the outside wheel, the differential has to compensate this difference.
This is where the spider gears come into the game.
It sounds like you're gonna have to pull the 3rd member & take a peek inside.
 
Why do they call it the 3rd member.... you mean the whole inter unit... and yes every one tell me that the wheels should spin under no load meaing off the ground. But it wont. Could it be low on Fulid... Just asking
 
Pour the friction modifier in and drive it. That may be all it needs.
Just ask Mustang owners if that stuff is required. They'll testify.
 
i had the exact same thing.i had used the auto zone tranz x friction stuff,started doing what yours is doing.i added g.m. brand additive,no more problems.
 
What is the best brand to use..... I will try and run out today and get some.

I think I would skip the part stores and go to a dealership for it.
What Ford had back in my time stunk to high heaven. If it hasn't changed, don't spill it on ya.
 
does Chrysler still sell the stuff

Extreme Dodge down here in Jackson still does. $8.99 for a 4 oz bottle. I'd bet your local dealer does as well.

I would change out the gear oil and add a bottle of it. Hopefully the unit isn't damaged.

People sometimes get confused on the friction modifier as they think it makes the suregrip act tighter, when in fact it loosens the friction on the clutches for normal driving, to keep them from prematurely wearing out.
 
I picked up a Bottle of Friction Modifier I will put into car in the Morning....
I will keep all posted....
 
Someone siad that the Ford Product is good stuff..... ????
I use the Ford friction modifier in my Mitsubishi Starion rally car with a tight LSD rear; does the job well. No more lurching around paved parking lots and still grips like heck when it should. Felt like the rear end was going to pop out of the car or a halfshaft was about to explode without it.

That stuff sure does stink; it's like gear oil stink concentrated 10x. So don't get it on you just before a hot date! (And I wrote this before reading Redfish's post; sounds like a common experience!)
 
The Ford modifier is very good.

If you have 2pc side gears do you know what your spline engagement is?

If you pull the axle how does the end look? Have you measured in to the cross shaft, and compared it to the axle end to retainer dimension to see how much space is between axle end and cross shaft?
 
Well today I added the Ford Modifier and quess what no more Noise,,,,, Thanks guys for all your help, One again THANKS...
 
no problem.when mine was doing this i swore it sounded like it was comming from the pass.front.had my buddy ride with me leaning out the window and determined it to be from the rear
 
Hey Richard this isn't related to the problem but I noticed in your post # 6 you asked why they call it the 3rd member. That's because it's the 3rd part of the drivetrain. Engine is #1, trans #2, rearend #3. Just an old time nickname
 
I was having some bearing and gear problems(lots of noise) with my Challenger after I purchased it. It had been sitting since 1981 or so, so I thought perhaps the bearings were having issues after sitting for over 20 years. Not having the tools to do it, I took it to a customer of mine at the time that did diffs., among other automotive work. For whatever the reason, I never was charged for the labour, only the parts. I thanked him, and drove the car home. No issues, no noise. I went to the local hangout here that night, and when I was backing the car up, it sounded like the whole rear end was ready to fall out. The next day, I was speaking with a fellow that worked for a company that only did diffs and he said to get rid of all the oil in the diff, go to my local GM dealer, buy 3 quarts of diff fluid and 2 bottles of GM posi additive. Followed his advise, put the fluid and additive in and like you PROBLEM GONE. I never did tell my customer of the problem, because of the no labour charge, but needless to say, I never sent anyone his way for diff work. Diff by the way was the 489 case, 3:55 Posi.
 
Thanks Buddy

Hey Richard this isn't related to the problem but I noticed in your post # 6 you asked why they call it the 3rd member. That's because it's the 3rd part of the drivetrain. Engine is #1, trans #2, rearend #3. Just an old time nickname
 
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