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Rear differential bad?

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97marooneclipse

10+ Year Contributor
44
0
Nov 4, 2010
Saratoga, New_York
I bought a 1997 GSX 5 speed with low miles and a bad motor. I replaced the motor and everything has been going smooth except one thing. There is a terrible vibration when in power (around 3500 - 4500 RPM's) it has the stock t-25 so it's at full boost when floored. I've checked the u-joints and carrier bearings with nothing unusual. The rear diff bushings are also good I can barely even budge the diff while using a pry bar. Also has a clunk if you let out the clutch fast, not launching but just letting it out quick. Is there a way to see if the differential is bad? Thanks in advance.
 
If it's doing it at a certain rpm - doesn't seem like it would be the diff. Sounds more like something to do with the tranny or transfer case. The diff usually makes a whirling noise when its going out, if it was out - it would just break some teeth (which you would constantly hear - super loud) or lock up all together.
 
I don't feel the vibration in the shifter and the transfer case is brand new. I can hear and feel the noise and vibration in the rear.
 
Did you buy the correct transfer case with the correct spline count for your transmission?

95-96 had a different spline count than 97-99. <-- (if I remember correctly, but not 100% on the years, but there was a change during the refresh of the 2G)
 
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Drop in some redline fluid and see if that helps. How loud is it from a scale of 1 to 10?
 
About a 7 its real noticeable. I think it's too much play between the ring and pinion
 
*bump* I would buy a rear diff then, make sure the stamp labeled "BFH" matches with the one you buy. I've seen a few people selling them in the classifieds section.
 
What's the BFH stamp? I have another rearend out of a 95 talon that I was going to put in. It's the LSD so I know I have to swap axles to but what else has to be done?
 
I think it's too much play between the ring and pinion

That's a good theory. It fits the location of the noise, the thump when you switch from coasting to power, and it can easily cause a speed-dependent noise as you hit something akin to the resonate frequency of the meshing of the gears.

With the car off and out of gear and the emergency brake on, slide under and see how much you can rotate the prop-shaft. It shouldn't be much.
 
I have all new engine mounts in. The motor definitely not moving that much. I will try getting under it after I get out of work tonight and see how much it turns. I will let you know after what my findings are.
 
What's the BFH stamp? I have another rearend out of a 95 talon that I was going to put in. It's the LSD so I know I have to swap axles to but what else has to be done?

It varies on auto/ 5 speed models and so fourth. The gearing is different, I remember I bought a replacement and it didn't fit correctly. Waste of time and money
:ohdamn:
 
Ohh I see. Well there both out of 5 speed cars. Its a LSD and out of a 95 talon that's going into a 97 non LSD.
 
Ive always been told that the 2ga and the 2gb diffs and transmissions were different.
2G a/b AWD drivetrain differences - Page 2 - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com
read post #18. from a very reliable source.

Yes the transmissions and transfer cases are diff they have to be matched. I was told by Tim Zimmer when I talked to him on the phone about it that all and he told me that all 2g rear differentials have the same gearing.

Limegrntaln- I only have the noise while accelerating, not deaccelerating.
 
If it's slop in the rear pinion, then it can produce noise on accel, decel, or both, depending on the particulars of the slop.
 
There was a similar thread not to long ago,but I'm not sure how to post up that thread.Anyhow the clunk and vibration that the other guy had was from the axle bearing coming out.Might be worth checking into:thumb:hope this helps

Maybe check the rear control arm bushings,strut issues,dont overlook a bad bushing in the rear
 
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Haven't been able to get under it yet to check but I'm going to check the axles when I get it up I have a slight feeling that's what it can be.
 
Just read this whole thing; it's an inner C/V joint/joints. Could be front or rear. Pull the guts out of them, and you'll find divots worn into the inner cups. When torque is applied, you can feel the bearings rolling in and out of those divots. It generates a hell of a vibration that dissapears when you coast, decell, or travel a steady speed.
 
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