12-Bolt Popping and Binding - Update w/Dyno sheet & Video
#1
TECH Apprentice
Thread Starter
12-Bolt Popping and Binding - Update w/Dyno sheet & Video
So in December I had my 12-Bolts bearings replaced and new set of 3.73 put in by a new shop due to another shops error and ruining the bearings. Well drove it home seemed ok and so it's sat till a couple weeks ago it was upper 50s clear roads took for a spin. Seems like the more I drive the car the worst it starts popping from the rear end and really feels like it's binding up.
It has an Eaton Posi with Moser 30 spline axles (passenger side was replaced due to bend) and am thinking that my Eaton is screwed up now. The rear pops when turning especially going in roundabouts and starts popping hard randomly when going straight, coasting, or very light cruise speed.
Thanks everyone
Update:
Well got the car tuned by The Shop Inc. here in Lincoln, NE a couple days ago and they did a great job straightening out the old Mail Order tune. The Shop told me when I stopped by to see how things were going it made 466 at the wheels on his Mustang Dyno with a really long flat torque curve. So I think this 408 likes the 102mm setup. But he got the rear end popping issue straightened out, and it was a fluid issue. Chad thought I was crazy when he test drove it as the rear made zero pops but then out of the blue it did it to him luckily. But after changing the fluid out all is well so far .
Added Dyno Sheet
It has an Eaton Posi with Moser 30 spline axles (passenger side was replaced due to bend) and am thinking that my Eaton is screwed up now. The rear pops when turning especially going in roundabouts and starts popping hard randomly when going straight, coasting, or very light cruise speed.
Thanks everyone
Update:
Well got the car tuned by The Shop Inc. here in Lincoln, NE a couple days ago and they did a great job straightening out the old Mail Order tune. The Shop told me when I stopped by to see how things were going it made 466 at the wheels on his Mustang Dyno with a really long flat torque curve. So I think this 408 likes the 102mm setup. But he got the rear end popping issue straightened out, and it was a fluid issue. Chad thought I was crazy when he test drove it as the rear made zero pops but then out of the blue it did it to him luckily. But after changing the fluid out all is well so far .
Added Dyno Sheet
Last edited by neblackshirts; 03-14-2017 at 04:45 PM. Reason: Adding words
#3
TECH Apprentice
Thread Starter
Would a pinion angle way out of alignment cause these symptoms I've described?
#4
TECH Veteran
iTrader: (4)
An Eaton posi(clutch plates) and Auburn posi(cone clutch) are very sensitive to NOT having the additive in them. Without the additive,they grab-slip-grab-slip-grab,sounding like popping/knocking. The sound/noise is very audible inside the vehicle but barely audible outside.
A pinion angle WAY OUT OF PROPER ANGLE because the driveshafts' front u-joint and rear u-joint are not synchronizing.
A pinion angle WAY OUT OF PROPER ANGLE because the driveshafts' front u-joint and rear u-joint are not synchronizing.
#5
LS1Tech Sponsor
iTrader: (16)
Are you sure the torque arm isn't loose at the rear end? It will make those popping sounds when turning if it is. Bob
__________________
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
#7
TECH Apprentice
Thread Starter
Trending Topics
#8
TECH Apprentice
Thread Starter
Does anyone have a recommended fluid to use for the Eaton Posi over what Eaton recommends the GM Dexron LS? This Camaro will see much more street/highway time over track time if that matters.
Thanks again everyone
Thanks again everyone
#9
Launching!
iTrader: (12)
Join Date: Jan 2009
Location: Cranford, NJ
Posts: 221
Likes: 0
Received 0 Likes
on
0 Posts
I bought a 12 bolt used from someone and had the same issue. I assumed they did not add diff lube so I changed the gear oil and used 2 bottles of diff lube. The rear still popped so I added 2 more for the hell of it, assuming I'd be tearing the rear end down anyway. Within 10 miles of adding the extra diff additive the popping subsided. I would honestly drain the fluid, replace with some non synthetic gear oil of your choice and toss in more than the recommended amount of additive.
#10
TECH Enthusiast
iTrader: (5)
I had a alburn in my S-10 for 15 better yrs and out of the blue its tarted doing that. I couldn't think of why,I pulled it down and really found nothing. It was old so I thought i'd replace it. Bought the same (cone) type and redid the rear.I installed all new bearings set it up and it worked ok. I had an on/off noise so I opened it up made a few shim adjustments and put it back together. it started popping jerking and all kinds of **** just like the first posi,I was pissed. I put in some more additive and it went away,that was last summer .
#12
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,241
Likes: 0
Received 79 Likes
on
70 Posts
Thats gonna make everything worse. But I agree, it sounds posi related. Some harshness should be considered normal as your suspension gets more aggressive.
#13
TECH Apprentice
Thread Starter
But not sure what you mean exactly on "thats gonna make everything worse". Are you meaning this due to is being a crossmember mounted torque arm? Also do you think I can hurt anything driving a bit with the rear popping? I have to drive it about 15 miles to the shop to have it looked at but definitely don't want to break the Eaton Posi.
Thanks for chiming in I know you defiantly know your suspension setups.
#14
TECH Senior Member
iTrader: (96)
Join Date: Aug 2007
Location: Turnin' Wrenches Infractions: 005
Posts: 24,241
Likes: 0
Received 79 Likes
on
70 Posts
I agree with you on the suspension seeming harsh especially with everything changed. I'm not sure there nothing stock except for the k-member. The harshness is something I need to get used to for sure.
But not sure what you mean exactly on "thats gonna make everything worse". Are you meaning this due to is being a crossmember mounted torque arm? Also do you think I can hurt anything driving a bit with the rear popping? I have to drive it about 15 miles to the shop to have it looked at but definitely don't want to break the Eaton Posi.
Thanks for chiming in I know you defiantly know your suspension setups.
But not sure what you mean exactly on "thats gonna make everything worse". Are you meaning this due to is being a crossmember mounted torque arm? Also do you think I can hurt anything driving a bit with the rear popping? I have to drive it about 15 miles to the shop to have it looked at but definitely don't want to break the Eaton Posi.
Thanks for chiming in I know you defiantly know your suspension setups.
#16
TECH Apprentice
Thread Starter
OK so while bored at work I stumbled upon a video that has the exact 100% same popping and sound as from my 12-Bolt rear-end as I was experiencing but would even pop randomly while going straight. Since the tune being done and having the shop add some friction modifier it has improved drastically but is still there just not to the degree as it was before.
Yes it's a Ford sorry and hope owner doesn't mind but it's about 2 minutes into the video:
Yes it's a Ford sorry and hope owner doesn't mind but it's about 2 minutes into the video:
#17
TECH Junkie
iTrader: (11)
Nice car, thanks for the ride! Your axle sounds exactly like the Detroit locker in my Mav. All I can think of on a 12 bolt is the clutches are setup tight. In fact, I can feel my '98 Dakota R/T (with the big 9.25" posi) chunking like that on tight turns. No sound, just the feel...
#18
TECH Apprentice
Thread Starter
Nice car, thanks for the ride! Your axle sounds exactly like the Detroit locker in my Mav. All I can think of on a 12 bolt is the clutches are setup tight. In fact, I can feel my '98 Dakota R/T (with the big 9.25" posi) chunking like that on tight turns. No sound, just the feel...
My 12-bolt didn't make that popping sound until a local shop replaced the bearings. But after I took it in for a tune and they added some friction modifier it helped out a lot. I would just be driving in a straight line and random pops would start. Turning I got but the going in a straight line spooked me, but I think this is a case of it being just the nature of the beast. The previous owner told me it was an Eaton Posi but others that have rode in my Camaro say that it reminds them a lot of a detroit locker. Maybe previous owner was mistaken on it being an Eaton but any how I came across that video and posted it to maybe give everyone an idea of what my Camaro was doing.
By the way nice Maverick, I bet that it surprises a lot of people. Ford always was able to make some pretty light weight packages that are great for todays modern tech.