FTBR 1350M and 5001 combo - Clunk Questions?

[BOOOSTD]

Hey guys,

I’ve done as much reading and trouble shooting on this prior to posting, but I’m stumped and could really use some suggestions.

My car is an 04’ vert with 43,000 miles. Suspension setup is basic with H&R race springs, Steeda FLSFC, MM C/C plates, Steeda Bumpsteer, IRS Eccentric camber adjusting bolts, IRS low profile bolts and performance alignment.

Just recently, I added the complete full FTBR bushing kit with the milled diff cover – FT 1350M and FT 5001 combo. While there, a new set of FR 373 gears with ARP gear bolts were added and everything inside was found to be in excellent condition. The gear was set to 8 thou backlash and everything has been gone over twice, ensuring that everything is tight, also double checking ½ shaft play, tranny play, DS play, U-joints etc which were all found to be within spec. Nothing really stood out as being the culprit.

The car handles like its on rails but now I am getting a clunk between gear shifts which is annoying. I understand that everything is solid now but it’s a pretty loud clunk. I can control the clunk if I let out the clutch super slow, but driving it with some spirit it clunks.

If you guys need anymore info on setup etc, please let me know; otherwise I’m all ears and ready to trouble shoot further.

Thanks!

 

[94slowbra1]

i assume you changed to a 9/16th bolt? also what about your trans mount?

 

[BOOOSTD]

i assume you changed to a 9/16th bolt? also what about your trans mount?

Yes, I used the 9/16 bolts that came with the kit.

The trans mount is stock. What is recommended there?

Thanks for your input!

 

[bssmith1220]

Interesting. I'm getting ready to get the ftbr kit as well. I hope it's not normal after that install.

 

[Kyle_KleinSS]

Standard cobra clunk, most do it. Mine you can hear good from 1-2 but after not so bad.

 

[BOOOSTD]

Interesting. I'm getting ready to get the ftbr kit as well. I hope it's not normal after that install.

I hope its not normal either....

Standard cobra clunk, most do it. Mine you can hear good from 1-2 but after not so bad.

Funny thing is that I didn't have the clunk between shifts before so its really bugging me. The clunk just doesn't sound normal to me.


Thanks for the input guys!

 

[Nightmare90gt]

Probably bad tranny mount. Get a gt mount drill out the rivets nut and bolts the gt mount to ur crossmember.

 

[BOOOSTD]

Probably bad tranny mount. Get a gt mount drill out the rivets nut and bolts the gt mount to ur crossmember.

I look into that, thanks for the input!

 

[Rich'sTRsvt]

If you continue to have problems you could always get a hold of FTBR to see if they can help. Bruce the owner is a member on here and goes by ac427cobra.

 

[BOOOSTD]

If you continue to have problems you could always get a hold of FTBR to see if they can help. Bruce the owner is a member on here and goes by ac427cobra.

I bought the FTBR combo kit, gear, camber bolts and race springs all from Bruce. I was hoping he was going to chime in and shed some light/expertise.

 

[Dave.O]

I just went through this, MM full bushing kit, replaced motor and transmounts, exhaust hangers, u joints, everything...
ended up being a worn out track loc, swapped for a torsen tr2 no more clunking, and it grips way better coming out of corner, faster on throttle

 

[BOOOSTD]

I just went through this, MM full bushing kit, replaced motor and transmounts, exhaust hangers, u joints, everything...
ended up being a worn out track loc, swapped for a torsen tr2 no more clunking, and it grips way better coming out of corner, faster on throttle

I really hope its not my diff but it will be something I look into. Thanks!!

 

[ac427cobra]

Hey guys,

I’ve done as much reading and trouble shooting on this prior to posting, but I’m stumped and could really use some suggestions.

My car is an 04’ vert with 43,000 miles. Suspension setup is basic with H&R race springs, Steeda FLSFC, MM C/C plates, Steeda Bumpsteer, IRS Eccentric camber adjusting bolts, IRS low profile bolts and performance alignment.

Just recently, I added the complete full FTBR bushing kit with the milled diff cover – FT 1350M and FT 5001 combo. While there, a new set of FR 373 gears with ARP gear bolts were added and everything inside was found to be in excellent condition. The gear was set to 8 thou backlash and everything has been gone over twice, ensuring that everything is tight, also double checking ½ shaft play, tranny play, DS play, U-joints etc which were all found to be within spec. Nothing really stood out as being the culprit.

The car handles like its on rails but now I am getting a clunk between gear shifts which is annoying. I understand that everything is solid now but it’s a pretty loud clunk. I can control the clunk if I let out the clutch super slow, but driving it with some spirit it clunks.

If you guys need anymore info on setup etc, please let me know; otherwise I’m all ears and ready to trouble shoot further.

Thanks!

You are going to hear drivetrain backlash much more clearly now that you have removed those pathetic rubber front diff mounts and replaced them with solid aluminum front diff mounts. Everything in your diff should have been gone through when you did your gears. We've had cars that were really loud and then after a proper diff rebuild, you could hardly hear them. I'd monitor it for a while to see if it gets worse.

In the meantime you can read up on this:

http://fulltiltboogieracing.com/faqs.htm#NVH_increase

The Dynamatting will help a lot. You can try a double layer if need be.

I hope that helps.

 

[BoostedByV]

ima guess its the welded nut on the irs frame that holds the bolt that goes through the rear diff mount

 

[BOOOSTD]

You are going to hear drivetrain backlash much more clearly now that you have removed those pathetic rubber front diff mounts and replaced them with solid aluminum front diff mounts. Everything in your diff should have been gone through when you did your gears. We've had cars that were really loud and then after a proper diff rebuild, you could hardly hear them. I'd monitor it for a while to see if it gets worse.

In the meantime you can read up on this:

http://fulltiltboogieracing.com/faqs.htm#NVH_increase

The Dynamatting will help a lot. You can try a double layer if need be.

I hope that helps.

Thanks Bruce for the input, I certainly appreciate it. Obviously, its not what I want to hear at this point about it possibly being the differential, but if I have to rule it out then I will replace it.

This is probably going to be a dumb question but I will ask anyways - if I return the front and rear mounts to stock stuff will that soften things up or defeat the entire purpose of the kit?

Thanks!

ima guess its the welded nut on the irs frame that holds the bolt that goes through the rear diff mount

Can you expand on this please - I'm all ears....Thanks!

 

[ac427cobra]

Thanks Bruce for the input, I certainly appreciate it. Obviously, its not what I want to hear at this point about it possibly being the differential, but if I have to rule it out then I will replace it.

This is probably going to be a dumb question but I will ask anyways - if I return the front and rear mounts to stock stuff will that soften things up or defeat the entire purpose of the kit?

Thanks!

I'm never going to recommend that because stabilizing the diff housing is critical to fixing the shortcomings of the IRS and protecting it from self destruction.

 

[03cobraracer]

I have a slight clunk in mine when shifting but I'm used to it and only does it if I shift a certain way. I've had more trouble with noise when I back out of my steep driveway and the rear suspension clunks/bangs since I put this new IRS in. Something loosened up on me. I tightened up all the mounting points once before and it went away for a few days then came back again. Stubborn bastard ha

 

[BOOOSTD]

I have a slight clunk in mine when shifting but I'm used to it and only does it if I shift a certain way. I've had more trouble with noise when I back out of my steep driveway and the rear suspension clunks/bangs since I put this new IRS in. Something loosened up on me. I tightened up all the mounting points once before and it went away for a few days then came back again. Stubborn bastard ha

Mine also does the same....I put it in reverse and hear clunk as if something is settling into position. She stubborn alright!

 

[Midnight_Cobra]

ima guess its the welded nut on the irs frame that holds the bolt that goes through the rear diff mount

This was the problem on mine. The stock weld cracked and the nut was loose, I just had mine rewelded and it's solid now.

 

[BOOOSTD]

ima guess its the welded nut on the irs frame that holds the bolt that goes through the rear diff mount

This was the problem on mine. The stock weld cracked and the nut was loose, I just had mine rewelded and it's solid now.

Sorry, I'm a newbie IRS guy and not sure which one is the welded nut :bash:
Could someone please post (if possible) a pic of where this welded nut is? I'm starting to really miss my SRA

Thanks guys!