Differential....

[BCC93QT]

Okay guys, starting to get a slight thud coming from the rear when i tap the gas. No doubt its the differential. is it just isolators and bushings that need to be replaced? Also I hear i can go poly from the Z32 is this correct? Ill start doing some searching i think i remember a write up on this.

[MinisterofDOOM]

Z32 poly bushings work, yes. I need to do the same thing. Another possible cause for the clunking is subframe bushings, so you may want to check into that as well.

[Q451990]

I don't have an explanation for why - but check your EGR valve's function. When I had a bad control solenoid on my old Q I had a clunk in the rear that went away after I fixed it. I thought it was unusual - but I could duplicate the noise and cure it by plugging and unpluggin the control solenoid.

My clunk was most noticable at low speeds... driving in neighborhoods and such.

Heath

[BCC93QT]

Yeah i noticed it when shifting gears when keeping the gas pedal still as well. Thinking about just taking the diff out of my parts car and throwing it on there. I can just rehabilitate it while its out and have one ready for when that one starts going

[Q451990]

Definitely check the EGR function too though... my first Q made it to over 200K without a clunk - except for the time that the EGR wasn't working at about 120K.

Heath

[MinisterofDOOM]

I wonder if that's my issue. That would seem to make more sense to me...Rob put Z32 poly diff bushings in this car, so they should NOT need replacing yet. Sounds like the times the thunk occurs match up with what you're describing. If it's just the EGR valve I'll be happy...much less work, even if the part's pricier.

[Q45tech]

EGR is cut off during idle and acceleration only operative during warmed up steady speed above 40 mph [1350 rpm].

[Q451990]

Like I said... I'm not sure why it worked this way. I'm working off of memory from about 10 years ago. Maybe I will unplug the EGR control solenoid on my current Q to see if I can recreate it...

Heath