I am noticing a distinct clunk sound when accelarating and releasing the gas pedal at low rpms. Is it time to replace the u joints?

Diff strap or support. Or both...

 

Can you point out that part? Any pic?

Grab the differential and see if you have any movement up and down at the nose, smaller end by the driveshaft. 

The rubber wears out on the differential support and makes a thumping noise.  Yours still has the sticker so I'd think it's been replaced since 1972? 

Can't advise on the strap, never fooled with one of those.

Edited September 5, 20186 yr by siteunseen

 I agree with checking the differential. I replaced my support and strap because of a clunk as you described. While you're under there wrestling with the differential looking for movement, check the u-joints too. There shouldn't be any movement in them.

The proble shows up and is more noticeable when driving at slow speed up slope entering the parking of my building. Whenever i accelerate after releasing the clutch i can hear the "clunk" coming from the rear of the car. I took it to the mechanic and he didnt find any play at the u joints. Do yoi think i should invest i  a new set of u joints plus the differential strap and support?

How about you have the diff mount and strap checked for wear or slop first? Don't throw parts at a problem that isn't necessarily there...

How do i check this?

Good times man...good times.

You can get thumping from the ends of the mustache bar also.  The diff twists when you apply power, or torque from deceleration.  If the mustache bar bushings are loose you'll be able to lift the end of the bar up by hand.  

19 minutes ago, Zed Head said:

Good times man...good times.

You can get thumping from the ends of the mustache bar also.  The diff twists when you apply power, or torque from deceleration.  If the mustache bar bushings are loose you'll be able to lift the end of the bar up by hand.  

 

10 hours ago, siteunseen said:

Grab the differential and see if you have any movement up and down at the nose, smaller end by the driveshaft. 

The rubber wears out on the differential support and makes a thumping noise.  Yours still has the sticker so I'd think it's been replaced since 1972? 

Can't advise on the strap, never fooled with one of those.

 

43 minutes ago, jalexquijano said:

How do i check this?

How about you do as the other members have suggested in this thread already? Seriously, this is test you or a mechanic can do quite simply. 

15 hours ago, jalexquijano said:

This is a nice looking undercarriage though.  Very clean.  No leaks.  Wish mine looked like that.

But, you should get some soft pads for your mechanic to use on the lift arms.  He's denting things and lifting in the wrong spots.  Each lift probably adds a little bit more damage.

Thanks for the advice. I guess the differential insulator part number is 55415 N4301. Whats the strap part number?