SirKnightTG

Is it normal for the rear end to clunk when down shifting? Usually, I only get the clunk when the car shifts into 2nd. When I'm in D and it shifts into 2nd (hitting about 20mph when coming to a stop) it'll usually do it most of the time but it's kind of quiet. When I pull the shifter down into 2nd myself at that speed, the clunk is much louder. I don't remember if pulling into 1st if it clunks or not...maybe. Pulling the shifter down to 3rd is usually ok. I do that a lot.

Sometimes it'll do it when I take it out of O/D, but it's kind of rare. I take it in and out of O/D ALL THE TIME and 99% of the time it's ok. This is mainly a 2nd gear thing it seems.

I put in a Dynotech 3.5" aluminum DS but it still clunks.

About two years ago, Ford rebuilt my rear end b/c they said it was noisy when I brought it in for my noisy torque converter issue (which they said nothing was wrong with). Maybe they didn't do something right? It's been like this ever since but I didn't really pay much attention to it until now since I manually shift it more often now.

Ford did that when I was in warranty, now I'm way out of it. I want to get 3.73's anyway and maybe that'll help?

JA66

My car (manual) is quite clunky unless I shift really smooth, but I have the stock 2-piece DS, do I'm not sure where my noise is coming from. Maybe your driveshaft is getting a bad u-joint? Probably not that likely seeing as how you hopefully don't take your mustang through creeks (my other vehicle is a jeep) but it could be possible that they forgot to grease it? Has is squeaked any?

If it is your rearend, re-gearing would get rid of the clunk if the person re-gearing it does it right. Put your stang on jacks, set the e-brake, put the car in neutral, crawl under there and try to turn the driveshaft, you will be able to tell if its the rear-end most likely, because you will be able to clunk it back and forth a bit. Could also see if there is play in any u-joints, although unlikely.

Offtopic- Could you tell a big differnce power wise when you put in the Alum DS?

SirKnightTG

There's not a big difference but maybe a little though. It's kind of hard to tell. I know there is a difference since the laws of physics says so.

It is nice knowing it's MUCH stronger than the stock two piece.

jahudso2

I never get clunking when I downshift, but I am pretty good at rev matching. However, I always get clunking during upshifts. Its disappointing to hear that a new d/s wont fix the problem.

desslok40

Check this out, I had a local shop look into a similiar clunking issue, they noticed alot of play in the rear end, they looked in the differential and found a bearing washer was out of tolerance, contacted a ford dealer who confirmed the spec and sure enough the angle of the washer was wrong (hence wrong part!!!), they shipped a new washer and and replaced, clunking is almost totally gone, funny though it must of come from factory like that !!! FORD $@%! Makes you wonder if there are any other "wrong" parts on the car from factory.

Riptide

Is this really a "problem"? If the car drives fine, has driven fine for thousands of miles, and probably will continue to do so then...?

Honestly these are kinda noisy cars. Be it interior rattles or clunky strut mounts or whatever. It's just how they are. I'm not crazy about it either, honestly I'm not, but if you want some smooth refined car then why not a BMW or a Mercedes?

SirKnightTG

I'm going to try replacing the trans fluid and see if that helps. My 95 V6 stang would get clunking sounds when its fluid needed replacing.

It has been like this for many thousands of miles, maybe 10s of thousands. I really don't remember when it started.

But I do plan on putting 3.73s in anyway.

SirKnightTG

The noises do not bother me. Infact I really don't notice them except the for rare squeek I get from between the passenger air bag door and dash.

So either mine doesn't have many noises or I just tune them out.

RICVA05

I noticed mine made the noise after my tuner adjusted the shifting patterns on my car after it was tuned.

samus720

mine has the same clunking noise when downshifting from 3rd to 2nd and it is more apparent if I shift it manually between those two. I've never been worried about it as I figure it's probably just a noisy tranny to begin with. Mine also whines a lot right before it shifts if its under high pressure (WOT). Sounds like a miniature supercharger.