I think something broke HELP!!!

[c4fly]

2 days ago I did a launch on the street with a small burnout.

Now when Im driving between 1500-2000 rpms (5th or 6th gear) and only between that, the car bucks and hesitates and when I give it gas between those rpms I hear a big clunk and/or bang sound and the car jerks back and forth (like huge play in drivetrain). Even when Im coasting in that range down a hill in gear it starts to buck and a back and forth hesitation.

I drove it last night hard a few times and powershifted and it is as smooth as glass. I dont get whats going on when Im cruising between 1500-2000 rpm. Its never been like that before. Anyone have this happen or know whats going on?

 

[ac427cobra]

2 days ago I did a launch on the street with a small burnout.

Now when Im driving between 1500-2000 rpms (5th or 6th gear) and only between that, the car bucks and hesitates and when I give it gas between those rpms I hear a big clunk and/or bang sound and the car jerks back and forth (like huge play in drivetrain). Even when Im coasting in that range down a hill in gear it starts to buck and a back and forth hesitation.

I drove it last night hard a few times and powershifted and it is as smooth as glass. I dont get whats going on when Im cruising between 1500-2000 rpm. Its never been like that before. Anyone have this happen or know whats going on?

Sounds like you damaged or blew your OEM rubber differential mounts. Not that hard to do actually. Or you could have possibly damaged a halfshaft.

There's also a possibility you have a rear hub bearing/halfshaft retaining nut issue.

It's hard to diagnose a car over the internet and you might well imagine.

See link in my sig for more information regarding the IRS.

:thumbsup::coolman::beer:

 

[c4fly]

How can I figure out what it is?

What and how do I check the stuff?

 

[Wicked46]

Get the car up in the air and look at your diff bushings and inspect your halfshafts.

 

[c4fly]

When i drive it hard or hit the gears I dont get anything clunking or banging under car. It only happens when I coast in gear or cruise between 1500-2000 rpm. Is that weird? Shouldn't I have other issues if something is broken? I try to get it up as soon as I can. Its pissing me off this problem.

 

[FSUstang]

Sounds like a diff bushing. I am dealing with this issue myself right now.

 

[FSUstang]

In my case it feels like the rear end is kinda floating from left to right.

 

[ac427cobra]

In my case it feels like the rear end is kinda floating from left to right.

I would check your halfshaft to rear hub retaining nuts. 36mm socket, 240-250# of torque.

If they are loose, you most likley need a rear knuckle bearing and or possibly a rear hub as well.

FWIW

:thumbsup::coolman::beer:

 

[Fat-cat]

Like others have said put the car up on stands and pull the rear wheels off and check for play in the shafts. Also you and go under the try and move the diff around. Should not be able to move it very much. If it has give you probably have a bushing problem. My guess is something in the rear is loose or coming apart.

if you coasting along at like 2500 rpm and give it a touch of gas does it make a banging noise ? When i did my diff brace i took the dampener off and forgot to space out the busing and the diff would tq side to side and do what your describing.

 

[c4fly]

if you coasting along at like 2500 rpm and give it a touch of gas does it make a banging noise ? NO

I just put in the Kenne Brown front aluminum Differential bushings yesterday. When I took the old ones out they looked pretty crushed, the rubber was pealed off the metal, pretty beat up...etc. I have 83,000 miles on the car and Im 2nd owner. I also tossed the big heavy block that was bolted under the diff too. A local mustang performance shop said to ditch it.

Going to drive it around today and see if the new bushings fixed the problem. I HOPE it did!!!

 

[ac427cobra]

if you coasting along at like 2500 rpm and give it a touch of gas does it make a banging noise ? NO

I just put in the Kenne Brown front aluminum Differential bushings yesterday. When I took the old ones out they looked pretty crushed, the rubber was pealed off the metal, pretty beat up...etc. I have 83,000 miles on the car and Im 2nd owner. I also tossed the big heavy block that was bolted under the diff too. A local mustang performance shop said to ditch it.

Going to drive it around today and see if the new bushings fixed the problem. I HOPE it did!!!

With all of the information available today, there simply should not be anyone running OEM differential bushings in their car any longer. :read:

 

[c4fly]

I hear ya! I eventually want to upgrade everything. I really want to get an IRS diff brace, Billetflow or Steeda. I've seen pics of the destruction that can happen and read a lot about the advantages. Thats deffinately the next upgrade.

 

[FSUstang]

yea i have the billetflow brace. it helps me sleep at night.

 

[c4fly]

CRAP :cuss:
My car is still doing it with the aluminum diff mounts in. What the hell.:??:

FAT-CAT - "If your coasting along at like 2500 rpm and give it a touch of gas does it make a banging noise? Not at 2500 only between 1500-2000 rpm, then when coasting down hill it does a hesitation and bucking with a slight banging.

 

[CamdZ06]

2 days ago I did a launch on the street with a small burnout.

Now when Im driving between 1500-2000 rpms (5th or 6th gear) and only between that, the car bucks and hesitates and when I give it gas between those rpms I hear a big clunk and/or bang sound and the car jerks back and forth (like huge play in drivetrain). Even when Im coasting in that range down a hill in gear it starts to buck and a back and forth hesitation.

I drove it last night hard a few times and powershifted and it is as smooth as glass. I dont get whats going on when Im cruising between 1500-2000 rpm. Its never been like that before. Anyone have this happen or know whats going on?

Man.. My car did that when i bought it and i ignored it, and when i took it to the track, I broke the Differential,etc. You better get that checked out. Im guessing its the gears. Do you have an upgraded Diff Cover? Brace? etc... You need those!

 

[CamdZ06]

2 days ago I did a launch on the street with a small burnout.

Now when Im driving between 1500-2000 rpms (5th or 6th gear) and only between that, the car bucks and hesitates and when I give it gas between those rpms I hear a big clunk and/or bang sound and the car jerks back and forth (like huge play in drivetrain). Even when Im coasting in that range down a hill in gear it starts to buck and a back and forth hesitation.

I drove it last night hard a few times and powershifted and it is as smooth as glass. I dont get whats going on when Im cruising between 1500-2000 rpm. Its never been like that before. Anyone have this happen or know whats going on?

Talk to ac427Cobra... He knows lots about how to bulletproof your IRS.. In my situation, since i broke lots of parts, i did a full SRA swap.. Love it!

 

[ac427cobra]

yea i have the billetflow brace. it helps me sleep at night.

Just so everyone reading this understands, the rear cover brace is to reinforce the rear cover and to prevent rear cover breakage. It will do NOTHING for wheel hop. :idea:

 

[c4fly]

Man.. My car did that when i bought it and i ignored it, and when i took it to the track, I broke the Differential,etc. You better get that checked out. Im guessing its the gears. Do you have an upgraded Diff Cover? Brace? etc... You need those!

No diff cover or brace yet. Im on the look out for one.

Just so everyone reading this understands, the rear cover brace is to reinforce the rear cover and to prevent rear cover breakage. It will do NOTHING for wheel hop. :idea:

Ac427cobra, where should I take my car to have the IRS checked out and diagnose the problem? a suspension shop, a mustang performance shop etc....? The mustang performance shop were the ones that said it was the diff mounts. So, thats kinda like a "strike one" for them. Im a little disappointed with them now that they kinda mis diagnosed the problem and they've been around for over 15 years. :shrug:

 

[ac427cobra]

No diff cover or brace yet. Im on the look out for one.



Ac427cobra, where should I take my car to have the IRS checked out and diagnose the problem? a suspension shop, a mustang performance shop etc....? The mustang performance shop were the ones that said it was the diff mounts. So, thats kinda like a "strike one" for them. Im a little disappointed with them now that they kinda mis diagnosed the problem and they've been around for over 15 years. :shrug:

If you check the dealer page on our website:

FTBR Recommended Dealer and Install Facilities

You will find a couple of CA dealers familiar with our parts. The flopping of the differential housing, mounted in 'toasted' OEM rubber mounts can be responsible for the 'Cobra clunk', leaking covers, broken covers and snapped halfshafts.

Wheel hop has to do more with control arm bushings, subframe bushings, tires and (lack of) a good quality full length subframe connector. If you have a vert, you are in for some special requirements to eliminate wheel hop totally and completely.

My best advice is if you're not that familiar with working on cars, find a friend that can help you with your car and get involved in the fix yourself! We have compiled a plethora of information on our site regarding the IRS:

Full Tilt Boogie Racing

I hope that helps.

:thumbsup::coolman::beer:

 

[Canuck03SVT]

CRAP :cuss:
My car is still doing it with the aluminum diff mounts in. What the hell.:??:

FAT-CAT - "If your coasting along at like 2500 rpm and give it a touch of gas does it make a banging noise? Not at 2500 only between 1500-2000 rpm, then when coasting down hill it does a hesitation and bucking with a slight banging.

Where did you get your diff bushings from?