[Christian1LE]

Just throwing this out there for anyone that tracks their cars a lot. I was hearing a "thud" sound from my rear end and found out that my diff was moving around. I thought I had a bad bushing but upon further inspection my differential carrier bolt that holds the back of the diff to the subframe came loose.

It would be a good idea to mark this bolt (if it's not already) and check regularly to make sure it's not moving. Reference picture below, and a video of the issue linked as well. I made a post in the maintenance forums but figured I would also post here because it's more track related than regular street driving.

Note: This is technically a 1 time use bolt, It's super tight as you can see but it still came loose. I ordered a new bolt and I plan to use some locktite on it when I put it back in. Bolt part # is 11611275

[N Camarolina]

Thanks for posting this Christian. It's display of altruism like this that helps make this forum such a fantastic resource. I track mine so have a definite interest it checking mine. I have two additional questions if you don't mind:

1) Can you please estimate the total number of track days you've done before the loose bolt sound appeared (I know you do other types of events, so please do your best to convert the "other events" to track day equivalents)?


2) Since the carrier bolt is one time use, what's the best way to check it's tightness without deforming it? Would it be appropriate to setting the torque wrench to 135ft/lb and apply for to check that it hits that torque before the bolt actually turns?

[Christian1LE]

Absolutely,

1) No need to estimate, I can give you an exact number. 40 events, including 36 trackdays and 4 hillclimb days. I didn't feel anything until I was putting it back up on the trailer leaving my last trackday, so It got loose during that last session sometime. I do need to estimate the track miles though, that is about 5,500 miles.

2) My carrier bolt was marked from the factory with a blue mark that shows where it is supposed to be. If it's not marked I would suggest to just set your torque wrench to 162ft lbs and try to move it, if it doesnt get any tighter then it definitely hasn't moved yet. For reference mine was backed out by about 100 degrees.

[carguy55]

Good post. I'll have to check mine next chance

[Badmojo]

Thanks for the tip. I checked mine and it was paint marked from the factory.

[WhiteMale]

Ive been chasing a clunky sound in the rear with my 23, I'll check this out.

[That1guy_tim]

great info! Thank you!

[JTRATX]

Thank you for posting. I just at the track this past weekend and will add this to the post inspection.
Was the part # for the bolt correct?

[Christian1LE]

Originally Posted by JTRATX

Thank you for posting. I just at the track this past weekend and will add this to the post inspection.
Was the part # for the bolt correct?

I'll let you know in a couple of weeks, I am lifting the car up and doing a bunch of stuff and the diff lockout will be on the list, that's when I'll take the old one out and see if it matches with the one I bought.

[cdb95z28]

Good find, Thank You.

I'm showing part #11611275 for this single use bolt.

BOLT,DIFFERENTIAL CARRIER REAR
AG, AH, AJ, AK37-67 * (SINGLE USE)
Callout: 5

List Price: $2.77

[cdb95z28]

The two different part #s have two different thread specs. Also the 11611275 has a captured washer where as the 11609598 has a flanged head. Should be easy to see what appears to be the correct #.

[cdb95z28]

The 11609598 appears to be a rear lower shock mounting bolt. It is also a single use bolt. Still worth keeping if you've already purchased.

BOLT,REAR SHOCK ABSORBER
AG, AH, AJ, AK37-67 * (SINGLE USE)(M12X1.75X80.9)

[Christian1LE]

Ok thanks, I've updated original post with correct part #. Where did you get that schematic from? Way more clear than what I was able to find.

[cdb95z28]

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