Technical Clunking noise in the rear axle

I finally have brakes on my 4 door deuce I recently trade for and now that I am able to drive it at speeds above 20 miles per hour I noticed on acceleration when I let off there is a noticeable clunk when I lift.

We had it in the rack and the universal joints are fine and I was told there was recently a new rear rear installed 3:42.

What should I look for in trying to decide what to do about the problem.HRP

 

I hope the rear is a Ford. Pull 3rd member and check back lash.

 

Chock the front wheels, jack up the rear and put it on stands, put the trans in neutral, and rotate the driveshaft back-and-forth to check for excess backlash.

Then check all of the bushings, mounts, etc.

 

If the rear is quiet otherwise, I'd check the suspension components first.
Again, jack it up and have a friend go back and forth between low and reverse, with the brakes on..Observe and listen.

 

On mine the plastic bushing inserts in the rod ends were knocked out. Replace them - it should be OK.

http://www.speedwaymotors.com/Four-...lt-Set-of-8,1583.html?OriginalQuery=910-08015

 

It is a Ford. HRP

 

My old rear I had in the Ford has considerable backlash in the pinion, no clunk. But I would look there first, then the u-joints, spring bushings, trans mount.

 

I had a similar type of problem on a old but, OT, Chevy van - took it in to a shop to have rearend repaired - turned out problem was in the tail shaft of trans - sounds move/carry - as stated above need to raise it up safely secured and with others there to help you and run in gear

 

Developed a clunking noise in a older Chevy positraction rear end one time and was told to add more
of the posi lubricant.
Didn't even know that stuff existed.
Added some and the clunk went away.
Is the Ford rear a traction-lok?

 

The noise is only heard after accelerating and taking my foot off the gas..clunk..only one time,the noise is no continues. HRP

 

shock mounts?

 

danny I had the same prob in my 41 pu 8.8ranger rear end turns out it was tracloc. and didn't have the right gear oil. just my .02 tom

 

Usually happens after a long, straight dive, followed by a sharp turn.Doesn't sound at all like the case here.

 

Is this an open differential?

I ran a Detroit Locker in a Jeep for a while. It made some funny noises on occasion.

 

Try some thin grease on the trans output shaft. GM had a grease for that years ago. The clunk was when stopped and let off the brake.

 

Sounds like a u joint to me , it may look good overall but put her in the air and twist the driveshaft

 

I could easily imagine it being something shifting or settling in the suspension but you might also take a look at the transmission and crossmember mounting points. Is there any place where the exhaust runs close to the body or chassis?

 

The friction modifier quiets down the internals. Using a product like the Valvoline VV831 oil, this has the modifier already in it. Sometimes the right lube makes a big difference.

 

It's got a 8" Ford rear end. HRP

 

Since I didn't build the car when I had it on the lift I went over the car checking all the nuts and bolts and everything was tight and all the bushings are new. HRP

 

If that R&P is stock ford it's what 37 -38 yrs. old ? could be just worn out , excessive backlash , spider gears worn , axle splines worn ,etc.

 

Does the make the noise shifting from forward to reverse? If not I would look at suspension first.

 

I had a clunking in the rear end under my 34 when I would accelerate and when I would turn corners. So I attacked the problem systematically from the easiest/cheapest to fix to the most difficult/expensive to fix. Don’t forget to turn the garage radio off (and heat or A/C if it’s loud near where you work on the car) so you can listen for noises on the car.


1. Drive Shaft: Check both drive shaft U joints. Crawl under the car with it in park and twist the drive shaft by hand. Grab near each u joint and try to twist and shake the crap out of the drive shaft. You can easily pull the drive shaft and check each u joint for further inspection.


2. Shocks: Check the shocks. Have someone lay under the car and watch the shocks while someone else bounces up and down (and lifts up) on the car to run the shocks through their travel. You can put the jack stands under the rear end instead of under the frame to get enough room to get under the car and still have the suspension travel.


3. Shock Mounts: look at the upper and lower shock mounts for cracks where they are welded to the rear end and where they are welded to the frame.


4. Hanging brackets: Depending on how your rear end is hung under the car (parallel leafs, 4 link, mono-leaf). Check each bracket that attaches the rear end to the car. If its parallel leafs, check the spring perches that weld to the rear end also. If you have 4 link bars, check the bushings or the hiem joints.


5. Rear end easy stuff: Check the easy stuff on the rear end first. To check for a axle bearing being bad, look for leaks and dribbling next to each left and right axle seal. Jack the car up and use jack stands. Check the bearing by grabbing the wheel (think bear hugging the rim and tire) and shake the crap out of it. If an axle bearing is really bad, you’ll know it. Also check for bearing noise by putting the car in neutral and turning the tire. Try to turn each tire from left to right real fast (like you’d turn a steering wheel super-fast from left to right to make a kidnapper lose control of a vehicle and wreck) in order to check for bearing play. Listen to the third member while a buddy does this for any unusual sounds. Check the fluid level of the rear end.


6. Rear end hard stuff: Start taking it all apart to check each component. Pull the 3rd member and check the pinion yoke. Does it have play? Is the seal leaking? Perhaps someone crushed the crush sleeve too much and then backed it off. Check the backlash of the ring gear and the pinion gear. You’re going to need to really clean the third member up and look for hairline cracks in the carrier. Look where the long pinion shaft (the pin that goes through the pinion) for cracks in the pinion itself. The pull each axle and check the axle wheel bearing and seals.


For my car, it turned out that the actual pinion was cracked. It was also an old 8” ford rear end. You can get the axle bearing and seals from your local parts store. You can get a third member rebuild kit from speedway. Just make sure you do NOT have an older 8" third member from a 57-64 Ford Galaxy. They don’t make the front seal for it and you’ll have to get a new third member housing, or a whole new third member. The seal on them looks like a tea cup saucer and is about 5” opposed to the normal seal which all other 8” and 9” third member use that is about 3 ½”. To easily tell, just go to the parts store and ask for the front seal for the pinion yoke. Then crawl under the car and look at it to see if it is the same size.

 

If that R&P is stock ford it's what 37 -38 yrs. old ? could be just worn out , excessive backlash , spider gears worn , axle splines worn ,etc If it's a new setup , then anything ,pinion depth , carrier bearing setup and/or preload could be "off"

 

The early (and popular for rodders as these were in the first generation Fairlanes and Falcons and the right width, '62 through about '65) 8" Ford rears were known for pinion bearing failure....

 

Mine was when putting it in gear and stepped on the gas..Thought it was a u-joint or suspension but it was the clutch packs.

 

When it is on a lift, things change and may not show any looseness in parts. See if you can find a ditch to pull over and crawl underneath. Something may show up as an obvious problem while it is on all fours. Just a suggestion since a similar thing happened to me and I had to check it that way before I found the problem.

 

I agree with this as much more strain and tension are on the drivetrain and suspension when actually moving down the road versus static/jack stands. No advice but good luck with your analysis. Let us know what you find.

 

Sounds like it needed more than additive then.When you drive straight ahead , the clutch packs are just along for the ride. Otherwise ,the clutches would have had to be so worn that the side gears were driving outward and making noise that way. Again...more than additive needed.
BTW, we still don't know if Mr Primer's car has clutch packs.