clunk when shifting in reverse

[kubesh]

Hi every body, new guy here, I have a 65 coupe with a c4 auto and every time I put the car in reverse I get a big clunk. is there a bushing on or around the differential? If so where? thanks

 

[RGS0907]

Hi every body, new guy here, I have a 65 coupe with a c4 auto and every time I put the car in reverse I get a big clunk. is there a bushing on or around the differential? If so where? thanks

Before you tackle anything to big, check the U-Joints (on your driveshaft) first, it's probably that.

 

[rbohm]

generally the front U-joint takes the most abuse, and thus wears out first. check it for free play, and if there is any replace it.

 

[rsweld]

ditto to the 2 above.

 

[dbfarr]

if you replace your u joints, take the drive line to a shop have it balanced and install spicers. The cheap GNB crap never lasted me more than six months, ... mmmmm busted u joints, spinning driveshaft, stranded in November.

On another note, don't let me send you astray, but when my trans clunked into reverse, I had a bad motor mount. 'Might wanna check those.

 

[RGS0907]

if you replace your u joints, take the drive line to a shop have it balanced and install spicers. The cheap GNB crap never lasted me more than six months, ... mmmmm busted u joints, spinning driveshaft, stranded in November.

On another note, don't let me send you astray, but when my trans clunked into reverse, I had a bad motor mount. 'Might wanna check those.

+1 on the motor mount too.

What is GNB?

 

[JonK]

I had a clunk in forward and reverse, though it was my UCA, found that my motor mount bolts (thru bolt and block bolts) could be spun by hand, engine to trans bolts were also loose, seller stated that it had a rebuild 5yrs. ago, hope they weren't loose all that time. Doesn't hurt to check all the driveline bolts and the cond. of your motor/trans mounts but I bet you'll find as mentioned above that it's ujoints.
Jon

 

[Bitter]

I vote for U-joints. That's a classic symptom.

 

[dbfarr]

GNB

Gnb is the brand for the garbage u joints that Schucks / Orielly sells. I think I've gotten them at Napa too, really lousy quality. They cut loose and cause frowns nearly every time...

I've been working on this car for nearly five years now, getting really tired of doing anything twice. In fact, I'm getting to the point where I won't even touch my wrenches unless I have quality parts!!

 

[JDS68Stang]

If the car drives fine at all speeds with no vibration etc... most likely then it is the motor mount(s) as said.

I checked my U-joints by hand on my old 68 with my brother who's also a gearhead and both seemed fine, car would start shaking in drivetrain at around 30 MPH.
I discounted $500 off when I sold it for that reason and new owner said new U-joints fixed the problem, so can't always tell by hand checking I learned that one the hard way.