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subarooo 09-15-2013 04:27 AM

Diff is binding?
Alright so i had a 4.10 lsd in the car and everything was working fine. Took the car on the street and did a couple aggressive pulls and on the way back to my shop the car wouldn't move. If i stopped accelerating the car would literally stop almost like i was applying the brakes. Limped it to the lane way to my shop after a couple minutes, opened up first gear and it spun the tires the entire way down the driveway (gravel road). But when i was stopped with car in neutral and no ebrake on i couldn't move it for the life of me. So i let it sit for about 20 minutes, jacked the car up with it in gear, stepped on the gas and the wheels spun. The second i let off the wheels stopped. Got flustered and put it on the ground. Took the jack out and it started to roll by itself....

So i assumed the diff was dicked. Just bought a 3. something diff and welded it. Booted it down the street and everything was fine. Did a quick round about and headed back for the shop when it started pulling the back end down. Its not the ebrake, but i dont understand how it could be the diff.

Any ideas?

Btw it has an rb25 in it running around 15 psi. Which is why i though the diff was blown.

frankie591 09-15-2013 11:38 AM

As a comparison, there are guys running 1000hp through medium case diffs without issues, so I dont think the power is the culprit.

frankie591 09-15-2013 11:40 AM

if you weld a diff and any tiny pieces of spatter get on the ring gear or the pinion it will cause major binding issues so I'd check that they are both clean and free of spatter

subarooo 09-15-2013 01:08 PM

Anyone have any helpful info? Spatter is deffinetely not the culprit.

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Yamahammer 09-15-2013 07:42 PM

So changing the differential did not have any effect on the issue?

What transmission do you use? If this problem exists in neutral as well that leaves the output shaft bearing, the hanger bearing, the diff bearings and the wheels bearings. I couldn't imagine any of these causing such a problem. Do each of the wheels spin freely when in the air?

Does the ebrake still work on both wheels? The shoes could have torn off the backing plate and gotten wedged or some shit.

subarooo 09-15-2013 08:00 PM

So I think I may have found the problem, or Atleast part of it. The drive shaft is hitting the chassis just before the u-joint. But for some reason if I let it sit over night an come in the morning it'll be fine and the wheels will be free. But if I take it for a hard rip it seams to mash onto the chassis and sit there. I'm wondering if shimming the diff would help. Any thoughts?

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frankie591 09-15-2013 08:03 PM

its hitting before the middle or rear u-joint?

subarooo 09-15-2013 08:57 PM

Rear. Just before the diff.

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Yamahammer 09-15-2013 11:33 PM

How is that possible? The diff is bolted solid to the subframe. There is no play between those components. Im very interested to see that. Can you take a picture?

subarooo 09-15-2013 11:36 PM

I can take pics tomorrow. Essentially the diff doesn't move, your right. But the subframe does have some play on a stock setup and from what I can see its supposed to. That's why there's subframe bushings and a diff bushing. Subframe bushing are for the ride as well.

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Yamahammer 09-16-2013 09:10 AM

Okay cool. Lets see whats going on there.

SamE30e 09-16-2013 05:05 PM

The shaft shouldn't come close to the subframe. Can you hear any weird noises while it's driving?

subarooo 09-16-2013 05:13 PM

I can't hear any noise, but the motors way to loud to hear over. Ill post a pic, it's touching just before the subframe.

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subarooo 09-16-2013 11:20 PM

1 Attachment(s)
Attachment 118404

Kinda hard to see, I painted it to know Forsure it was rubbing. I know it used to touch last year with the stock motor when I really hammered on it. But it never stopped the car from moving. I took it out for a boot tonight again and same shit. Locked up tight on the way in. Jacked it up and started to loosen the center support bearing and it came a little loose.

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Yamahammer 09-17-2013 08:47 AM

So its hitting the fuel tank in this picture. If you do indeed think this is a driveshaft problem then maybe take it out, feel the output shaft and diff input ear and see if they both spin freely.

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