9.25 Sure Grip Axle Problems

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1977newyorker

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hi, everyone. it's been a little while since i posted. i need help with a grinding noise coming from the axle on my 77 NYB. we thought at first it was axle bearings, but those turned out to be fine. I've replaced the gear oil, including the Mopar friction modifier in Valvoline 80-90 non-synthetic, but something in the rear axle is making grinding and clicking noises, and at slow speeds actually affects the movement of the car. the noise only begins after 10-15 minutes of driving, so it's a hot thing. Any ideas? thanks.
 
Get it hot, take the plate off twist the drive shaft and see what's loose or broken. I'd bet to see it, it won't need to be hot though.
 
Hmmm I have a 77 as well, I just recently completely rebuilt my axle due to a similar issue, and that turned out to be the bearings.. when you say you had yours checked out and they were OK, how exactly did you check them? If my having the bearings checked, you mean, you didn’t see any metal in the fluid when you took the Diff cover off, that’s not always a tail tail, which is why I asked exactly how you had them checked. you have a bearing at the yoke and a crush sleeve As well..
also! May sound like a silly question, but are your rear drum brakes adjust correctly, if there is dragging, that would certainly cause an issue and clicking as you described.
Keep us posted..
 
I did the brakes, in an attempt to address this issue. That and the drums had never been removed in 46 years. My mechanic tested the bearings at the ends of the axle, on the lift, but there was no play or leaks. Working cold, he was unable to reproduce the noise. We're now looking inboard, so yoke bearing definitely on the list.
 
Get it warmed up so you can hear the noise, then have you Mechanic pick it up on the hoist and run it idling in gear. He may have to run the speed up some, but if it's a bearing he should be able to hear it, a stethoscope really helps
 
when the noise is at full, At very slow speed, you can feel it catch and slow the car. I have a guy that does general work on older cars, but he's familiar with old mopars. regular shops won't touch it. If he finds something beyond his skill, i'll have to go to a specialty shop.
 
1977newyorker said:
you can feel it catch and slow the car.
Click to expand...
should be very easy to find. i feel bad for people with old cars that have to find competent people to service them. finding anybody competent to service anything now is difficult but with cars everything is so obscenely expensive and a person ends up paying whether the job is done right or not.
 
Just a thought here... Lot's of talk about axle bearings, but I'm thinking it may be the pinion. IIRC, that 9 1/4 has a crush sleeve and I wonder if that is compromised and screwing up the mesh.

Could also be the pinion bearing.
 
Big_John said:
Just a thought here... Lot's of talk about axle bearings, but I'm thinking it may be the pinion. IIRC, that 9 1/4 has a crush sleeve and I wonder if that is compromised and screwing up the mesh.

Could also be the pinion bearing.
Click to expand...
Good call John, I mentioned that as well..
 
9 1/4 does have a crush sleeve but it doesn't go bad of itself. it's just something to tighten against the same as on a shimmed pinion. it doesn't set the depth. that's done with shims behind the inner bearing. the sleeve is for setting the preload instead of shimming the outer bearing. i've seen several rears with bad outer bearings. they'll cause the gears to howl like a tea kettle on low boil and on inspection it's possible to feel the yoke be loose and hear noise turning it by hand. i've never had one "catch and slow the car". this could happen if a bearing cage is bad but i've never seen it and i think it would have caused the bearing to be severely damaged by now.
 
following up - Justin may be right. my mechanic took it loose and was unable to identify any problem. the yoke bearing, the crush sleeve, gear teeth, everything looked fine, no play. we're going to try a heavier oil as a last shot before i take to an axle shop for a rebuild $$. i'm currently running 80-90 per the manual, but i've seen on here a couple of folks running the 70-140. that's all we can think of, within the limitations of our combined axel knowledge.
 
G'Day,
Going to Mention Something That I am Certain Does Not Refer to Your Problem But Just a Curiosity Thing.
Back in about 1990 Odd a Few of Us Club Members Hired a New Ford Fairlane for a Trip of about 4,000 Miles.
After Driving for Quite a Few Hundred Miles we Stopped for a Feed & Refuel.
Upon our Resuming our Journey, the Vehicle Developed a Severe Shudder Whenever We Attempted to Reverse.
Also a Much Lighter Shudder at Slow Forward Speeds.
We Eventually took the Vehicle to a Ford Dealer along the Way Who Cheerfully Drained the Differential & Replaced
the Oil with the Right Type.
Apparently the Factory had Supplied ALL the New Models with the WRONG LSD Oil.
O.K.
If You do Find the Solution to Your Problem, Please Get Back to Us.
As with All Problems the Rest of Us can Use the Education. LOL
All the Best,
Tony.M
 
It very well could be the sure grip unit...the clutches and steel plates wear over time, this alone can cause some horrible sounding noises and driveability issues. And sometimes the splined teeth on the plates can break off causing the plates and clutches to misaligned and make all kinds of horrible noises and even worse driving conditions.
 
End of journey, the axle got a full rebuild. It's happy now. So far, the mechanic has been unable to pinpoint the offending bit.
 
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