Has anyone found a way to measure if an FD diff mount is out of spec, while the diff is still in the car? I was wondering if something like have a plumb bob attached on the upper diff frame and another attached to the diff and then jacking up the diff would show a measurable difference in what was initially a common spot between the two plumb bob strings? I would expect some change but if a large enough movement existed it may indicate a mount was excessively worn. I'm trying to find a rear of car clunk that has become noticeable after some changes that included the installation of a Samberg similar diff mount. Another idea I had was to create relative part movement indicators such as tiny safety wire in tension between parts and see if any break or deform significantly after a drive. Thanks.

 

You are aggressively overthinking this.... a rear end clunk can only be a few things. MOST COMMONLY the pillow *****. Have you checked the play in your pillow *****?

 

The stock differential mounts are oil filled to suppress nvh. While they can fail they don’t “clunk” in my experience. And it’s not a terrible job to replace them. “Clunks” tend to come from failed pillows ball bushings as mentioned…and maybe from toe link bushings.
And are you referring to a Samberg differential brace/cradle? That will likely really increase drive train noise and no amount of bushing replacement would kill it completely.

 

^All good points.

If a stock mount has failed it will ooze out junk. If you see a weeping mount, it probably needs replacing.

Also if you are at the point that you are doing some hard core diff brace you probably should have already put in poly diff mount bushings.

Dale

 

Based on your guys statements it is likely the pillow ***** as they have never been changed. The trailing arm / toe links are heim joint style and one of the pillow ***** for a trailing arm does seem to have a little play so that is a likely candidate.

 

No Pillows in trailing arms.
Pillows are in Upper control arm (1) and lower control arm (2)....and the Toe link (1).

 

Isn't the item in the lower control arm where the trailing arm connects considered to be a pillow ball? That is the item that seems to have some wear in my case.
Do you happened to have any complete lower control arms at this time?

 

I thought it was too, but it was back in the late 90’s when I last opened one of those arms up to remove/replace the p-b and I can’t recall now if it was that arm or the other one.