Sporadic gear noise

[turbosax2]

I've had this sporadic gear noise happen on two occasions now and it's got me stumped. Fresh fluids in the rear diff, t-case, and trans. The last instance it happened was over two month ago, and it just happened again today (I don't drive the car much). However, I did just drive the car for a few hours on Saturday and didn't have this problem.

On to the issue...
I was driving for about 3 miles before the problem happened. I was at a stop sign, and pulled off smoothly, like always (I've never launched the car), and the car started making a horrible noise that got louder/faster with speed. I'm not sure if it was more speed or RPM related since I only shifted into 2nd gear for a little bit. I put the car in neutral and rode for a little bit, then turned the car off while rolling, and braked - the sound didn't change with any of this except it got slower/quieter when slowing down. Despite the horrible noise, the car still drove fine and I didn't "feel" any vibrations really. I stopped the car after about a hundred feet, quickly shook the wheels, inspected what I could, no fluids leaking or anything appeared abnormal. Started the car back up again (no weird sounds at idle) and as soon as I took off again it started up again. Pulled into a driveway another hundred feet up the road and inspected again. Backed out of the driveway slowly (no noise then), and took off again and the sound had stopped completely and was fine for the rest of the 15 minute drive and the return trip. I'm not sure if putting the car in reverse fixed the problem or what.

Anybody have any clue about this or at least what I can look into? I'm stumped and the problem has only happened twice so it's hard to know much about it.

Pretty much everything suspension related in the front of the car is new, new brake pads/rotors, new front axles, new front wheel bearings, new tie rods, new control arms. The clutch/flywheel/t-case/trans/rear diff are the original factory pieces with 97,xxx miles on them and I've never abused them since I've owned the car.

 

[twicks69]

Eric, check the driver-side halfshaft for connection with the driver-side inner CV as it might have popped out, along with complete connection of the passenger side inner CV with the transmission. Maybe the passenger side seated the snapring on the axle, but is popped out causing the noise.

I will think of other things that can cause your symptoms.

 

[turbosax2]

I will check that out next chance I get. Thank you for the suggestion.

 

[turbosax2]

Everything dealing with the axles seems to be fine. No trans fluid or t-case leaks, axle boots are in good condition, and I checked the axle nuts to verify they were torqued completely.

An unrelated issue I did find though is that the driverside axle boot is rubbing against the plastic inner fender liner. I don't know why this is happening since the fender liner is unmodified, held up with all the proper fasteners, and doesn't appear to be damaged. I can easily cut out the section that is rubbing to fix the issue but I'm more interested why it's an issue at all. Anyone happen to have pictures of a 2g awd near the driver axle to compare? Maybe the boot on my GSP axle is just wider than OEM.

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I welcome more potential solutions to my problems

 

[turbosax2]

After comparing my old OEM axle to the GSP axle, I found that the OEM boot tapers faster and more than the GSP boot does, so the wider boot caused the rubbing. I cut the small portion off the shield where it was rubbing to resolve that issue.

 

[turbosax2]

The noise happened again a few times yesterday, but went away much quicker than before. I had my brother run alongside the car as I slowly drove it, and he thinks the noise was coming from the carrier bearing area. Would a bad carrier bearing make sense?

 

[twicks69]

It can happen....

Did you check the halfshaft to axle connection on the driver-side axle? I saw you discussed all the other points, but not specifically this.

 

[turbosax2]

Yes, that connection also looked fine. I wasn't sure exactly what I should have been looking for, but nothing looked out of the ordinary.

 

[1995gsx20g]

the carrier bearing could very well be the cause.

i have heard them make noise only while going up or down an incline.

when you go in reverse you load the carrier bearing in the opposite direction and most likely in your case put the bearing back in its place and stopping the noise.

with the car off i would put it in first gear ebrake off and rock it right before the motor spins while someone else is looking at the carrier bearings.

 

[JFZERO ECLIPSE]

Eric,

A buddy of mine with a vr-4 was telling me about a rattling noise coming from underneath the car. It didn't do it everytime he dirves the car only once in a while...He said that it only happens with partial throttle to about 50% and back down to about 10%....I decided to call and ask him to check the carrier bearings...

Both of his carrier bearing have massive freeplay....you can just grab the driveshaft and lift it up and down appox. 1/3" on the front carrier bearing and about 1/2" on the rear...Since hes broke I told him the cheap way to fix is the way it says to do it in the vfaq...

Just throwing out some ideas.....

BTW turbosax you have a pm....

 

[turbosax2]

Thanks for the input. How much play is acceptable on carrier bearings? I couldn't find a spec in the FSM.

Jim, I didn't get your PM yet.
Edit: got it

 

[viprez586]

Hard to tell but, measure how much free play you have and report back.
Do the VFAQ "mod" for temporary use until you find the time to rebuild the driveshaft.

Using silicone to fill the carrier bearings.

 

[turbosax2]

I will try to measure next time I work on the car.

As far as I know, the silicone fix is only for 1g's. 2g's have a different design that doesn't allow the "fix" to work. I read about one person doing it to new 2g carrier bearings before installing them on the driveshaft, but no information was given about how he did it.

 

[1995gsx20g]

iirc they go for around 70 a pop from mitsu

 

[snowborder714]

Eric told me the other day that one is $45 and the other is $40, so not nearly as much as we were thinking.

 

[1995gsx20g]

oh sweet. maby that was list.

 

[turbosax2]

I put together this list of everything possible to rebuild the driveshaft just to see how much I'd be looking at if it needs rebuilt. Some of this probably isn't necessary. Prices are from mitsparts.com

(3) MR470072 - Yoke recall kit (yoke, U-joint, caps, clips) - $30.28
MR165048 - Front carrier bearing – $40.62
MB837577 - Rear carrier bearing - $46.53
(4) MB288653 – Carrier bearing nuts – $0.91
MB505119 – Boot kit - $54.26
MB837300 – Joint kit - $187.58
(2) MA143517 – Nut - $3.37
(4) MB000938 – Bolt - $1.06
(10) MB154075 – Nut - $0.78
MB505107 – Snap ring - $2.38
MB505112 – Washer - $9.52
MB505213 – Flange - $48.77
(6) MB837273 – Bolt - $1.62
(4) MF450405 – Washer - $0.12
(6) MS450042 – Washer - $0.15
(2) MT203641 – Washer - $2.93
Total - $520

 

[1995gsx20g]

there's a thread somewhere on the forum about a shop that made him an upgraded 2piece driveshaft for $800 ill try and find it.

 

[turbosax2]

Ya, bbender had Shaftmasters make it (although they aren't currently selling them until an issue is resolved). Definitely an option if I can confirm that several parts of the driveshaft are worn. I'd sure feel silly rocking an aluminum driveshaft with a pretty much stock car though

 

[1995gsx20g]

yup..oh i didn't know that. yea i hear you on that one but for the price it might just be worth it.

 

[Calan]

Not sure on the 2G prices, but I picked up a brand new (rebuilt) factory driveshaft a couple years ago from www.WholesaleImportParts.com for somewhere around $520 after the core refund...IIRC. It was all three pieces, including new carrier bearings and u-joints with actual grease zerks, rather than the sealed factory type.

As for the silicone or Window Weld carrier bearing "fix", I would recommend not doing it. It's really hard to get it to cure with the driveshaft properly centered, and you can end up with some pretty nasty vibration.

 

[1995gsx20g]

i heard people having issues with some u-joints with zerks. they break real easy if the zerks are in the wrong spot.

 

[JFZERO ECLIPSE]

Thanks for the input. How much play is acceptable on carrier bearings? I couldn't find a spec in the FSM.

Jim, I didn't get your PM yet.
Edit: got it

Eric, According to the DSM Backup Manual, it states that Journal axial play is between .02-.06 mm or .0008-.0024" as the acceptable

I believe anything outside of the above spec is NOT acceptable, does it mean I'm crawling under my car to take a look...nah...but the next time I get it lifted I'll take a look....

But going off my car as it sits...when I last checked the parts I could not wiggle it or anything, it was really tight....

Edit: I could NOT find it in the 97-99 section of the Manual...I decided to take a look at the 90-91 pages and the above numbers are what I've found....

Granted the carrier bearing style did change from the 1g to 2g era....but since I couldnt find no more info regarding the "free play" specs...I decided the numbers looked good enough for me....

 

[turbosax2]

And that's for how much play should be in the carrier bearings? That spec seems ridiculously small for rubber flexing...

 

[turbosax2]

No measurements, but here's a video:

YouTube - DSM Carrier Bearings

The flex doesn't seem excessive to me, but I've never inspected another DSM to compare.

Also, on an unrelated? note, my rear backlash is 8mm, 3mm over the 5mm specification listed in the FSM. I wonder if this is a common problem that most people don't check?