Is it the Diff?

[elrichmeister]

WTF. You'd have to lock the diff pinion in place to determine driveshaft play. BUT...what would cause the driveshaft to have play in it? The CSB and the CV joint - those can be inspected relatively easy. I think your shop doesn't understand that your limited slip diff has backlash between the ring and pinion gears which causes the driveshaft some free rotation or play.

Then they did a half-ass rebuild. The machine to dynamically balance a driveshaft is VERY expensive. Unless they sent the driveshaft out to be rebuilt and balanced - they really didn't do the biggest reason why someone would pay to rebuild a driveshaft - and that's balance it.

one thing for sure, is the drive shaft was sent out to be rebuilt.

[Kcalhoun27]

Thanks for the response, yea unfortunately i don't have space to tackle this my self, so i usually have a shop do the work for me.

i get that, if you werent on the other side of the country id help you myself.
sounds like youve got a few shop related issues, so im sorry to hear that. On one hand, id want them to fix their work, but then again, i dont think id let them touch my car after what theyve done.
Best of luck with the fix, i think you can probably pinpoint the issue to the diff, it would be my next move if i were in your shoes. There are lots of members in CA, maybe they can help or at least give you a reputable shop to go to

[elrichmeister]

So just to update this thread. Answer Yes it is the Diff

Ended up taking the car to another shop to do an inspection, and they concurred with previous shop. Drive shaft rebuild and install was done correctly and looked great.

Issue is excessive play on the passenger side differential output shaft, Driver side axle has excessive side to side play.
They recommended that i have Differential rebuilt, and replace driver side axle at minimum.

Not sure why previous shop ghosted me, was asking for quotes on diff rebuild, i thought we had a good relationship.

New shop recommended that i get a rebuilt diff from diffs online, which was what i was already looking at. So ill most likely go that route and replace both axles, but sheesh those are expensive.

[332]

So just to update this thread. Answer Yes it is the Diff

Ended up taking the car to another shop to do an inspection, and they concurred with previous shop. Drive shaft rebuild and install was done correctly and looked great.

Issue is excessive play on the passenger side differential output shaft, Driver side axle has excessive side to side play.
They recommended that i have Differential rebuilt, and replace driver side axle at minimum.

Not sure why previous shop ghosted me, was asking for quotes on diff rebuild, i thought we had a good relationship.

New shop recommended that i get a rebuilt diff from diffs online, which was what i was already looking at. So ill most likely go that route and replace both axles, but sheesh those are expensive.

What ratio are you going with? Now is a good time!

[elrichmeister]

What ratio are you going with? Now is a good time!

Was planning on sticking to stock ratio, the car is mainly a street car, that I take to the canyons sometimes. It's also almost double the price for 3.91 upgrade on diffs online.

[332]

Was planning on sticking to stock ratio, the car is mainly a street car, that I take to the canyons sometimes. It's also almost double the price for 3.91 upgrade on diffs online.

You only have to do it once, if you are a street car and do canyons. Do a 3:85 ratio, its cheaper and a bit more for the street! I know how many times, I've regretted not upgrading parts when Its only a couple hundred extra bucks!

[siamkazi]

You only have to do it once, if you are a street car and do canyons. Do a 3:85 ratio, its cheaper and a bit more for the street! I know how many times, I've regretted not upgrading parts when Its only a couple hundred extra bucks!

Just saw this thread, went through all this in the past months or so. That rumble thing for the driveshaft happened to me, was a bad driveshaft. ended up replacing it with a used one off of FB for $100 and rumble went away.

https://www.youtube.com/shorts/HnUKmfAJ_nk

Regarding the diff, i bought a 3.91 from peaky parts, his name is Pedro and is in Portugal, 850 Euros, he has shims and everything else needed if desired. Unitrax in Corona did the install.

[elrichmeister]

You only have to do it once, if you are a street car and do canyons. Do a 3:85 ratio, its cheaper and a bit more for the street! I know how many times, I've regretted not upgrading parts when Its only a couple hundred extra bucks!

Yea it makes a lot sense, I will take it into consideration.

[elrichmeister]

Just saw this thread, went through all this in the past months or so. That rumble thing for the driveshaft happened to me, was a bad driveshaft. ended up replacing it with a used one off of FB for $100 and rumble went away.

https://www.youtube.com/shorts/HnUKmfAJ_nk

Regarding the diff, i bought a 3.91 from peaky parts, his name is Pedro and is in Portugal, 850 Euros, he has shims and everything else needed if desired. Unitrax in Corona did the install.

I’ll need to do some research and find out what parts I need to obtain for a diff rebuild. I’ll look into peaky parts thanks for the reference.

[bigjae46]

If it is the LSD unit causing the issue, you don't need to even pull the diff out. Remove the back cover and axles, pop the stubs off and remove the carrier covers while supporting the LSD unit. Depending on how careful you are, don't even need to change the bearings. If you have a V2, don't need to remove the ring gear. If it is a V1, you have to remove the ring gear. Technically you should replace the ring gear bolts, I reused them on my diff. I'd replace them if they are the original ones.

It will be a bitch getting it back in unless you have a second set of hands.

I'd be interested to see what the diff and LSD unit looks like out of curiosity. I still have a hard time believing that noise is a diff issue but also hard to tell from a youtube video,

[elrichmeister]

If it is the LSD unit causing the issue, you don't need to even pull the diff out. Remove the back cover and axles, pop the stubs off and remove the carrier covers while supporting the LSD unit. Depending on how careful you are, don't even need to change the bearings. If you have a V2, don't need to remove the ring gear. If it is a V1, you have to remove the ring gear. Technically you should replace the ring gear bolts, I reused them on my diff. I'd replace them if they are the original ones.

It will be a bitch getting it back in unless you have a second set of hands.

I'd be interested to see what the diff and LSD unit looks like out of curiosity. I still have a hard time believing that noise is a diff issue but also hard to tell from a youtube video,

From what the 2nd shop told, driver side axle has a problem. During a launch it has a lot tension and causing to axle to bind and make the noise, from what I understood.
Ill need to watch some DIff rebuild and rear axle videos to fully understand what is going on there.
I'm still considering doing a 3.91 or 3.85 ratio change, but i most likely need to find a shop locally who can do it, as its the more cost effective if I want to do a ratio swap.
I did get some references on this thread so ill reach out to them. I will most likely need to source the parts, but before i do that i want to understand how all these parts work.

The diff and 2 rear axles will be pretty expensive, so ill have a wait a bit, in the meantime ill do some research.

[bigjae46]

From what the 2nd shop told, driver side axle has a problem. During a launch it has a lot tension and causing to axle to bind and make the noise, from what I understood.
Ill need to watch some DIff rebuild and rear axle videos to fully understand what is going on there.
I'm still considering doing a 3.91 or 3.85 ratio change, but i most likely need to find a shop locally who can do it, as its the more cost effective if I want to do a ratio swap.
I did get some references on this thread so ill reach out to them. I will most likely need to source the parts, but before i do that i want to understand how all these parts work.

The diff and 2 rear axles will be pretty expensive, so ill have a wait a bit, in the meantime ill do some research.

The axle going bad makes a lot more sense. The driver's side axle has the exhaust passing underneath so the inner CV sees a lot of heat - it is usually the first CV boot that goes bad. When you come to a stop, all of that heat is going into that boot. Even worse if there is an aftermarket exhaust with no heatshield. I wrapped my exhaust with header wrap in that area...in fact I remembered that I need to redo that. I replaced the boots and repacked my axle CVs at 115k miles IIRC? The grease was water, literally ran out of the boot when I pulled it off.

The clunk from a worn out LSD is usually not as severe or loud.

Maybe unbolt the axle from the diff and see if the axle binds up at all. I'm pretty sure you can replace the inner boots without removing the axle. So you can remove the boot and inspect the CV. If the CV is bad, maybe you can find just the CV and send it.

[fattycharged]

I'd guess axle too, my cv grease was leaking out like liquid when I just replaced my diff with a V2…I bought the axle rebuild kit and should have done it then…


Sent from my iPhone using Tapatalk

[332]

From what the 2nd shop told, driver side axle has a problem. During a launch it has a lot tension and causing to axle to bind and make the noise, from what I understood.
Ill need to watch some DIff rebuild and rear axle videos to fully understand what is going on there.
I'm still considering doing a 3.91 or 3.85 ratio change, but i most likely need to find a shop locally who can do it, as its the more cost effective if I want to do a ratio swap.
I did get some references on this thread so ill reach out to them. I will most likely need to source the parts, but before i do that i want to understand how all these parts work.

The diff and 2 rear axles will be pretty expensive, so ill have a wait a bit, in the meantime ill do some research.

We can walk you through a diff rebuild, I've replaced many, It's always better to be lucky than good!