Differential problem
#2190925
11/06/16 09:09 PM
11/06/16 09:09 PM
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Joined: Jun 2006
Posts: 221 Illinois
Tinman761
OP
enthusiast
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OP
enthusiast
Joined: Jun 2006
Posts: 221
Illinois
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I had the third member rebuilt about 6 years ago. I had a 323 ring and pinion and suregrip installed. I also replaced the u joints at the same time. Ever once and a while I would notice a slight thump when I accelerated. It didn't happen all time, and I could never narrow it down. So today we are out enjoying the day, and now I'm getting a louder more noticeable thump in all three gears. Brought it home to check it out. Fluid is a little low. Doesn't smell burnt but the pinion area is extremely hot to the touch. Any ideas of what to do next. 1967 dodge coronet 500. Automatic trans. Thanks Joe
Last edited by Tinman761; 11/06/16 09:10 PM.
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Re: Differential problem
[Re: Tinman761]
#2191009
11/06/16 10:40 PM
11/06/16 10:40 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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in neutral I would wiggle the drivehshaft back & forth to check ring and pinion backlash. check ujoint bolts and trans mt bolts. Maybe check axle end play (doubtful on that tho). that'd get us started
live every 24 hour block of time like it's your last day on earth
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Re: Differential problem
[Re: Tinman761]
#2191018
11/06/16 10:49 PM
11/06/16 10:49 PM
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Joined: Aug 2003
Posts: 43,185 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,185
Bend,OR USA
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Do you know if it is the original third member or maybe a later one? The reason I'm asking is the later model "489" (the last three numbers on the casting number under the drivers side of the pinion gear ) third members had crush sleeves on the pinion gear to set the pinon bearings preload and they can do cause problems with the pinon gear running hot if they are not set up correctly Does the thump only occur going around corners while accelerating? If so maybe it is the posi causing that
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Differential problem
[Re: Tinman761]
#2191040
11/06/16 11:19 PM
11/06/16 11:19 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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how hot and how much backlash movement. I ain't a rear end guru but I think the heat might be (way) more telling than the BL but the more info the better so the guys that know what they are doing can (further) advise
live every 24 hour block of time like it's your last day on earth
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Re: Differential problem
[Re: Tinman761]
#2191150
11/07/16 01:15 AM
11/07/16 01:15 AM
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Joined: Apr 2003
Posts: 348 Texas Hill Country
Centerline
enthusiast
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enthusiast
Joined: Apr 2003
Posts: 348
Texas Hill Country
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I'm no rear end expert but here's my $.02. First, when was the last time you added the sure grip additive to the diff.?? Second, a clunk going around corners can be worn clutches in the sure grip... due to lack of lubrication and no additive or possibly a broken spider gear.
My best guess on the heat problem is the fluid is warn out and just can't provide the lubrication needed. Not sure how much this helps though.
Centerline 64 Dodge Polara 426 Street Wedge - For when I want to go fast 99 Corvette Z-06 - For when I want to turn corners
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Re: Differential problem
[Re: Tinman761]
#2193194
11/09/16 05:06 PM
11/09/16 05:06 PM
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Joined: Jan 2003
Posts: 10,563 Freeport IL USA
poorboy
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,563
Freeport IL USA
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The 1st thing I would check is to see if the pinion nut has backed off, put the rear end on jack stands with trans in neutral, turn the driveshaft slowly in one direction, then reverse the direction. What your looking for is how much the driveshaft moves before the tires change direction, should be almost immediately. If not, you need to find the source of the slop.
If that checks OK, the next thing I would do is set the car back on the ground and drive to the nearest fairly large blacktop parking lot. Once there, do a very slow tight figure 8 at least 7 or 8 times, then go for a ride and see if there is an improvement. If the car sits a lot, or isn't often turning corners, the sure grip lube gets squeezed out from between the clutches of the rear end. The figure 8s force the clutches to separate and allow the lube to get back between the clutches. The dry clutches make all kinds of noises. You may have to repeat the figure 8 thing a 2nd time, if there is no improvement after the 2nd time, the problem is elsewhere, its time to pull the center section and take a look. Gene
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