I'm SORRY . . . CLUNK . . . I . . . CLUNK . . . CAN'T HEAR . . . CLUNK . . . YOU.
J/K. I get it every once in a while, no biggie . . .
J/K. I get it every once in a while, no biggie . . .
Drivetrain CLUNK! YES or NO.
- Thread starter bassin247
- Start date
This issue isn't unique to IRS Cobra's but it is unique to Ford (and anyone equally cheap) manual transmission vehicles.
There is more than one place in the 8.8 Track Lock where slop in gears will generate backlash. The primary contributor is the interface between the spider gears and output gears. Backlash present at this point will *NOT* generate whine as would ring and pinion backlash.
In order to correctly set this lash the following steps must be performed.
1) Assemble the differential with thin shims under the positraction clutch stacks that guarantee an assembly with worse case narrow carrier/large spider and output gears will go together.
2) Press the output gears toward the spider gears (against the preload spring) and measure motion.
3) Add the measured dimension to each clutch stack shim.
4) Re assemble.
You shouldn't have to stress your gray matter much to realize that if the process stops after step one, time and money are saved. Ford sells cars to make money, not to create a pleasant driving experience. Profit will increase and Ford will still saturate the "Cobra market" if these cars clunk. Most cars will clunk due to their tolerance stackup. A few lucky buyers will receive units built with gears sized toward the high end of the tolerance window and/or narrow internal carrier dimensions and they will not clunk.
Another minor contributor is ring and pinion backlash. Ford also sets these up toward the loose end of the spectrum for similar reasons. Most of the backlash is due to the spider-output gears though for reasons outlined in an earlier post.
What can you do?
1) Buy a Track Lock rebuild kit.
2) Shim your spider-output gear interface tight.
3) (Far less significant) Shim your ring & pinion toward the low end of the backlash specs.
You might as well restack the center 3 discs in an alternating pattern while you're at it.
Repeat 1 & 2 periodically as the clutch stack thickness reduces with wear.
Or,what did I do?
1) Bought a preloaded Torsen T2R from reiderracing.com (no backlash, no clutches)
2) Set the box in my garage
***Stay tuned***
None of this is unique to the IRS cars. In fact the live axle cars have an added disadvantage that the correct shim thickness for zero backlash may prevent insertion of the spider shaft. This is due to the C clip design of the live axle.
My car is a '97. The spider posi clutch shims had to be adjusted as well as ring-pinion backlash to eliminate the clunk. Once done the ring-pinion wear pattern finally looked good as well.
Of course once that was done I had to go and swap in a sloppy '03 IRS. The majority of my backlash is definetely in my differential. Half shafts are tight as is the T45 which performed well with my rebuilt live axle. U-joints are fine and the pumpkin is not moving in it's bushings.
Ford builds these quick and sloppy. From that standpoint it is "normal", but you don't have to put up with it.
CLB
Edtitde for typoos
There is more than one place in the 8.8 Track Lock where slop in gears will generate backlash. The primary contributor is the interface between the spider gears and output gears. Backlash present at this point will *NOT* generate whine as would ring and pinion backlash.
In order to correctly set this lash the following steps must be performed.
1) Assemble the differential with thin shims under the positraction clutch stacks that guarantee an assembly with worse case narrow carrier/large spider and output gears will go together.
2) Press the output gears toward the spider gears (against the preload spring) and measure motion.
3) Add the measured dimension to each clutch stack shim.
4) Re assemble.
You shouldn't have to stress your gray matter much to realize that if the process stops after step one, time and money are saved. Ford sells cars to make money, not to create a pleasant driving experience. Profit will increase and Ford will still saturate the "Cobra market" if these cars clunk. Most cars will clunk due to their tolerance stackup. A few lucky buyers will receive units built with gears sized toward the high end of the tolerance window and/or narrow internal carrier dimensions and they will not clunk.
Another minor contributor is ring and pinion backlash. Ford also sets these up toward the loose end of the spectrum for similar reasons. Most of the backlash is due to the spider-output gears though for reasons outlined in an earlier post.
What can you do?
1) Buy a Track Lock rebuild kit.
2) Shim your spider-output gear interface tight.
3) (Far less significant) Shim your ring & pinion toward the low end of the backlash specs.
You might as well restack the center 3 discs in an alternating pattern while you're at it.
Repeat 1 & 2 periodically as the clutch stack thickness reduces with wear.
Or,what did I do?
1) Bought a preloaded Torsen T2R from reiderracing.com (no backlash, no clutches)
2) Set the box in my garage
***Stay tuned***None of this is unique to the IRS cars. In fact the live axle cars have an added disadvantage that the correct shim thickness for zero backlash may prevent insertion of the spider shaft. This is due to the C clip design of the live axle.
My car is a '97. The spider posi clutch shims had to be adjusted as well as ring-pinion backlash to eliminate the clunk. Once done the ring-pinion wear pattern finally looked good as well.
Of course once that was done I had to go and swap in a sloppy '03 IRS. The majority of my backlash is definetely in my differential. Half shafts are tight as is the T45 which performed well with my rebuilt live axle. U-joints are fine and the pumpkin is not moving in it's bushings.
Ford builds these quick and sloppy. From that standpoint it is "normal", but you don't have to put up with it.
CLB
Edtitde for typoos
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Clun clunk clun clunk yup normal
Ditto. My Callaway Camaro did the exact same thing, and that was with a new T-56 tranny, new aluminum driveshaft, and new SN450 motor. I'll live with it until it gets to the point where it is bad enough to complain about. No sense driving an hour to my dealer only to have him tell me it is within Ford specs and is "normal" at this time. And repeating that process more than once. When it gets bad enough (if that ever happens) my dealer will take care of it.
:burnout:
i took mine in and they told me the same thing...can't address the issue because they can't test drive it that fast...mine is at the dealer right now getting the loose bumper fixed....tommorrow i'm gonna see if a tech will ride along with me so i can get er up to 80..
i agree its a crock of dooky, seems like they would be better quality for 35g's..
( OOOPS.... Meant to post this on the vibe thread........ )
This is definitely wrong for a dealer to be declining to troubleshoot and fix a Cobra's vibe. Here are retorts that you can use:
- The car is designed by Ford to travel over 155 mph. Why can't you go half that speed?
- Does my warranty have a maximum speed clause?
- A Ford bulletin exists that identifies the problem along with remedies. This includes vibrations at various speeds. It also includes rear end and drive shaft replacement solutions.
- The work is included under warranty coverage. It will not cost the dealer anything.
- THE CUSTOMER IS ALWAYS RIGHT.
Get it fixed or get your local attorney general after the dealer.
:burnout:
This is definitely wrong for a dealer to be declining to troubleshoot and fix a Cobra's vibe. Here are retorts that you can use:
- The car is designed by Ford to travel over 155 mph. Why can't you go half that speed?
- Does my warranty have a maximum speed clause?
- A Ford bulletin exists that identifies the problem along with remedies. This includes vibrations at various speeds. It also includes rear end and drive shaft replacement solutions.
- The work is included under warranty coverage. It will not cost the dealer anything.
- THE CUSTOMER IS ALWAYS RIGHT.
Get it fixed or get your local attorney general after the dealer.
:burnout:
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offtopic, but today i picked my car up at the dealer for the loose bumper....they told me the reason it was loose was because the plant put it on wrong....great...makes me wonder what else they may have put on wrong....:mj:
My bumper is loose too. The Asst service manager said he went to the showroom and it was the same on the cobra there. Did he even look at my bumper? No! I had the tech look under and check and would you beleive 2 screws were missing? yep!!! I trust them!!!
Petzuk, you will have a tough time convincing a judge why anyone should be compelled to violate the law on your behalf just because you've asked them to do so.
Jim
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First, the bottom line:
My clunk is gone.
My slight gear whine under decel is gone.
I finally got the car in the air and pulled the pumpkin Friday night. Inside to my complete lack of surprise I found loose spider gears due to sloppy posi stack shimming. Also featured was .018" ring gear backlash.
I solved the loose spider gears/clutch shim issue by swapping my ring gear over to a Torsen T2R. Shimming the clutch stacks on the Track Lock would have removed the backlash just as well but the Torsen should stay tighter over time.
I set the ring gear backlash at .007 (I think). The dial indicator read between .006 and .009 depending on how it was set up. The wear pattern looked well centered.
While I was in there I also installed the M4304A cap stud kit and drilled/tapped/plugged a drain hole.
The car now drives like any other decent manual transmission vehicle. You can find a little backlash if you look for it (a small amount is required) but will not notice it otherwise.
This is all regarding my '97 with '03 IRS. I don't know how my T45 compares to a T56 as far as backlash is concerned. From what I have seen though I still believe the "clunk" is due to sloppy clutch stack shimming and ring/pinion setup.
CLB
My clunk is gone.
My slight gear whine under decel is gone.
I finally got the car in the air and pulled the pumpkin Friday night. Inside to my complete lack of surprise I found loose spider gears due to sloppy posi stack shimming. Also featured was .018" ring gear backlash.
I solved the loose spider gears/clutch shim issue by swapping my ring gear over to a Torsen T2R. Shimming the clutch stacks on the Track Lock would have removed the backlash just as well but the Torsen should stay tighter over time.
I set the ring gear backlash at .007 (I think). The dial indicator read between .006 and .009 depending on how it was set up. The wear pattern looked well centered.
While I was in there I also installed the M4304A cap stud kit and drilled/tapped/plugged a drain hole.
The car now drives like any other decent manual transmission vehicle. You can find a little backlash if you look for it (a small amount is required) but will not notice it otherwise.
This is all regarding my '97 with '03 IRS. I don't know how my T45 compares to a T56 as far as backlash is concerned. From what I have seen though I still believe the "clunk" is due to sloppy clutch stack shimming and ring/pinion setup.
CLB
Jim,
You statement is correct. How would suggest getting a high speed problem resolved???
Peter
Peter, I wish I knew. I have had trouble with my dealer replacing broken fog lights on my Lightning. And that was 3 days after I purchased the truck from them. I am looking into an '03 Cobra and test drove one today as a matter of fact. I would suggest trying to find a dealer that cares about fixing the problem. I know of one near where I live and that's where I got my problem fixed with my truck. I would expect them to help me as much as they could with any other problem. In my experience, the right dealer is what makes the difference... assuming there is a solution.
Jim
Jim
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Sounds like it's going to rip the axles off the snake.. Gotta love the feeling!
Something I found referencing a TSB on drivetrain clunk.
Make : FORD Model : MUSTANG COBRA : Year : 2003
Service Bulletin Num : 16069 Date of Bulletin: JUL 01, 2002
Component: POWER TRAIN DRIVELINE DIFFERENTIAL UNIT
Summary:
SOME COBRAS MAY EXHIBIT A CLUNK NOISE FROM THE DRIVELINE DURING A QUICK ACCLERATION JUST AFTER COAST
(TIP-IN CLUNK). *TT
Here is another one for the people who have a hard time shifting into first gear. I had this problem with the stock shifter.
Make : FORD Model : MUSTANG COBRA : Year : 2003
Service Bulletin Num : 16067 Date of Bulletin: JUL 01, 2002
Component: POWER TRAIN CLUTCH ASSEMBLY PEDAL/LINKAGE
Summary:
SOME VEHICLES WITH MANUAL TRANSMISSION MAY EXHIBIT A HARD TO SHIFT INTO GEAR CONDITION PARITCULARLY FROM A STOP INTO FIRST OR REVERSE GEAR. *TT
Make : FORD Model : MUSTANG COBRA : Year : 2003
Service Bulletin Num : 16069 Date of Bulletin: JUL 01, 2002
Component: POWER TRAIN DRIVELINE DIFFERENTIAL UNIT
Summary:
SOME COBRAS MAY EXHIBIT A CLUNK NOISE FROM THE DRIVELINE DURING A QUICK ACCLERATION JUST AFTER COAST
(TIP-IN CLUNK). *TT
Here is another one for the people who have a hard time shifting into first gear. I had this problem with the stock shifter.
Make : FORD Model : MUSTANG COBRA : Year : 2003
Service Bulletin Num : 16067 Date of Bulletin: JUL 01, 2002
Component: POWER TRAIN CLUTCH ASSEMBLY PEDAL/LINKAGE
Summary:
SOME VEHICLES WITH MANUAL TRANSMISSION MAY EXHIBIT A HARD TO SHIFT INTO GEAR CONDITION PARITCULARLY FROM A STOP INTO FIRST OR REVERSE GEAR. *TT
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and...?
Ford just states the problem? - is there anything more? This is good info, detail detail please!
Ford just states the problem? - is there anything more? This is good info, detail detail please!
Hey snakebite, is your rattle noise in the tranny like a finger going through a pocket comb? I had this problem. Sounded like every time I shifted, something was ticking wildly in the trans.
Took it to the dealer and they found that the noise was actually the power steering. A couple of bolts were loose and when the steering was pulled left or right at the "special" angle, ticky ticky ticky.
Surprisingly enough the dealer had 2 other Cobras in for the same problem. I guess torque wrenches have been banned at the plant?
:shrug:
Took it to the dealer and they found that the noise was actually the power steering. A couple of bolts were loose and when the steering was pulled left or right at the "special" angle, ticky ticky ticky.
Surprisingly enough the dealer had 2 other Cobras in for the same problem. I guess torque wrenches have been banned at the plant?
:shrug:
My car was in for another reason, so I had them do the TSB for rear-end pop/clunk. I think they just re-torqued some rear suspension bolts. Car drives MUCH quieter now, no funny noises when shifting gears.:beer:
yes, please post the details on how to correct or lessen...
fyi, my drive-line clunk is gone.
i swapped out my entire IRS & rear-end with someone else's & a few other fixes/mods were done at the same time. but i think the problem was either in the rear-end OR the differential bushings -- cuz mine were seriously degraded
i swapped out my entire IRS & rear-end with someone else's & a few other fixes/mods were done at the same time. but i think the problem was either in the rear-end OR the differential bushings -- cuz mine were seriously degraded
Can you elaborate a little more?
Did you swap out your IRS with another stock 03 IRS?
What mods were done?
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