G80 Making a Fuss?

LeedomtoFreedom · 03-14-2018, 12:41 PM

Only recently has a rumble occurred in my car, it seems central the the rear passenger wheel and ONLY happens during right hand turns.

All of the bushings have been replaced very recently, which leads me to believe it's related to the g80 acting up.

It almost seems like the g80 is engaging too quickly and because I have summer tires on, it makes a lot of noise and vibration.

any thoughts?

JohnMc · 03-14-2018, 01:06 PM

Jack it up, spin the wheels, see what happens.

It's basically an LSD with a very VERY low preload, that tightens once you exceed 100 rpm difference side to side (flywheels swing out, engage, it clamps down on the clutch pack).

On mine, it's barely noticeable as anything other than a normal open diff until you spin it fast enough.

LeedomtoFreedom · 03-14-2018, 01:10 PM

I jacked it up and couldn't get it to lock with my hands by spinning it. When I spin one wheel, the opposite wheel spins slightly. I couldn't notice any substantial play in the whole axle that might cause this.

LeedomtoFreedom · 03-14-2018, 01:13 PM

Quote:

the opposite wheel spins slightly

correction, it spins slightly in the opposite direction.

JohnMc · 03-14-2018, 01:18 PM

As it should. If you leave it in park or in gear (AT or MT) then the driveshaft won't turn and it will maximize the RPM difference. It's 'around' 100 rpm, on mine I had to really get it spinning pretty good before it would engage.

Although if you're not hearing any weird noises out of it from what you did, you probably don't have any issues with the G80 in turns. It's designed specifically to not engage unless there's a very significant wheel speed difference.

As well as being prevented from engaging at all, regardless of wheelspin, over roughly 25 mph.

LeedomtoFreedom · 03-14-2018, 01:21 PM

The flywheel has been cut from my g80, allowing it to engage whenever.

I have no place to start then, trying to figure out this rumble.

JohnMc · 03-14-2018, 01:42 PM

There's still a smaller set of flyweights that kick in to engage it at the 100(ish) RPM difference.

Wheel bearings?

2manyturbos · 03-14-2018, 01:49 PM

Just put your floor jack under either trailing arm and jack up one side of the rear axle. Make sure the jack is pointed in the same direction the car can roll. Start the car, put it in gear and ease your foot off the brake. After a couple of revolutions of the rear wheel that is up the G80 should lock and move the car forward. If it doesn't lock, something is broken or severely worn.

LeedomtoFreedom · 03-14-2018, 02:47 PM

So you want me to let the car roll on the jack on one side? like a crutch or something ?

JohnMc · 03-14-2018, 02:49 PM

You should be able to do it by hand.

Although in this case, we're not diagnosing if the G80 works, we're diagnosing a rumble in tight corners. The G80 isn't trying to kick in in a tight corner unless you're stomping on that gas pedal and spinning a tire.

LeedomtoFreedom · 03-14-2018, 02:59 PM

It usually doesn't happen going through quicker, longer corners. Just tight ones.

I recently had the thread about the vibrations in the drive-train. While I've basically sorted that, I'm curious if it's somehow related, even though I can't think of how it would be.

2manyturbos · 03-14-2018, 03:00 PM

Quote:

Originally Posted by JohnMc

You should be able to do it by hand.

Although in this case, we're not diagnosing if the G80 works, we're diagnosing a rumble in tight corners. The G80 isn't trying to kick in in a tight corner unless you're stomping on that gas pedal and spinning a tire.

I've had several that wouldn't lock when turned by hand, however, would almost instantly lock when one side is jacked up. I know you are trying to figure out a rumble. It could be a spider gear problem. It also could be that something broke in the G80. They supposedly get noisy when damaged.

OP, yes, like a set of training wheels, crutch, however you want so see it. If the G80 is working properly, it will lock and move the car forward. If you then put it in reverse and do the same thing, the wheel up in the air should turn 1-2 turns and the G80 will again lock, going backwards. If it behaves like that, it is working like it should.

FreeEMSFred · 03-14-2018, 03:13 PM

Interesting, both of the ones I have are trivial to engage by hand on the car or out of the car on axle stands - you can clearly feel the "knock" of the inertia of the other side attaching to your side.

JohnMc · 03-14-2018, 03:17 PM

Yep, jack it up, leave it in gear so it doesn't spin the driveshaft, spin spin spin clunk.

The junkyard G80 I got is apparently somewhat worn, it never really locked up all that solidly on the road, but you can really 100% feel it engage when spinning it by hand. Freely spinning *clunk* - can't budge it by hand.

And again, if it's not making noises while you spin it, you should probably start looking elsewhere. Regardless of it finally engaging or not.

LeedomtoFreedom · 03-14-2018, 03:19 PM

Alright guys, after I jacked up the car an hour ago, I went to drive it in my neighborhood making only right turns like a UPS truck, and found that it didn't happen a single time.

I'm not saying I've got the magic touch, but maybe I do? If anyone needs my services, my rates are reasonable.

LeedomtoFreedom · 03-14-2018, 03:21 PM

I'm obviously not convinced it's gone, but I'll wait and see. If it comes back, I'll test the g80 trying both methods.

2manyturbos · 03-14-2018, 05:03 PM

Quote:

Originally Posted by JohnMc

Yep, jack it up, leave it in gear so it doesn't spin the driveshaft, spin spin spin clunk.

The junkyard G80 I got is apparently somewhat worn, it never really locked up all that solidly on the road, but you can really 100% feel it engage when spinning it by hand. Freely spinning *clunk* - can't budge it by hand.

And again, if it's not making noises while you spin it, you should probably start looking elsewhere. Regardless of it finally engaging or not.

After selling you that one that didn't lock up hard, I test them all the way I'm describing, only, I block the front wheels and leave my foot on the brake a bit. They will lock hard and spin the tire on the ground when working correctly. I know that doesn't make you feel any better. The 740 we used to autocross would leave two stripes black as coal when the turbo hit if you weren't paying attention. It finally was abused enough it wouldn't even leave a mark on the outside tire when cornering. That locker has since been replaced with another one.

JohnMc · 03-14-2018, 08:38 PM

Did you sell me that one? I forget. I sort of half thought I'd grabbed it from a junkyard around here. I did grab one from a fairly low mileage 940 a few years ago, I've just been too lazy to sap them.

2manyturbos · 03-14-2018, 08:46 PM

Yes. I sold it to you and once installed, you mentioned in another thread that you were underwhelmed with G80 locker performance. It made me examine their performance much closer before pulling them. I encountered a couple of them that had so little power transfer I didn't bother pulling them. I've probably pulled and sold 20+ so far.

JohnMc · 03-14-2018, 08:52 PM

The condition probably depends more on the way they were driven than the miles the car has.

VB242 · 03-14-2018, 10:14 PM

I would think you could purchase new plates and restore it's function. I swapped some less worn ones from a rusty g80 into the one in my car when I installed it.

LeedomtoFreedom · 03-15-2018, 08:15 PM

I've made a liar out of myself. But in light of it's return, I had a thought.

My shocks are completely blown, rusty, and 40 years old. Could the combination of the shocks not dampening the wheels when they try to stick in a turn, like wheel hop?

Does this make sense ?

Wilford Brimley · 03-25-2018, 12:52 AM

LeedomtoFreedom · 03-25-2018, 12:49 PM

Quote:

Liar

I've got a real issue with you Wilford

Wilford Brimley · 03-25-2018, 12:57 PM

Quote:

Originally Posted by LeedomtoFreedom

I've got a real issue with you Wilford

03-14-2018, 12:41 PM	#1
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	G80 Making a Fuss? Only recently has a rumble occurred in my car, it seems central the the rear passenger wheel and ONLY happens during right hand turns. All of the bushings have been replaced very recently, which leads me to believe it's related to the g80 acting up. It almost seems like the g80 is engaging too quickly and because I have summer tires on, it makes a lot of noise and vibration. any thoughts?

03-14-2018, 01:06 PM	#2
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	Jack it up, spin the wheels, see what happens. It's basically an LSD with a very VERY low preload, that tightens once you exceed 100 rpm difference side to side (flywheels swing out, engage, it clamps down on the clutch pack). On mine, it's barely noticeable as anything other than a normal open diff until you spin it fast enough. __________________ '63 PV Rat Rod '93 245 16VT Classic #1141

03-14-2018, 03:13 PM	#13
FreeEMSFred Board Member Join Date: Nov 2009 Location: Kiwiland	Interesting, both of the ones I have are trivial to engage by hand on the car or out of the car on axle stands - you can clearly feel the "knock" of the inertia of the other side attaching to your side. __________________ FreeEMS.org - the open source engine management system My Volvo Adventure (No 56k). My non-Volvo turbo truck. My gold 1991 240 wagon! My blue 1990 740 16v sedan!

03-14-2018, 10:14 PM	#21
VB242 Mojo Stealer Join Date: Sep 2011 Location: Virginia Beach	I would think you could purchase new plates and restore it's function. I swapped some less worn ones from a rusty g80 into the one in my car when I installed it. __________________ 1980 primer JDM flares franken-242DL, 1989 silver 780 sienna rear spring nivomat delete

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03-14-2018, 01:10 PM	#3
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	I jacked it up and couldn't get it to lock with my hands by spinning it. When I spin one wheel, the opposite wheel spins slightly. I couldn't notice any substantial play in the whole axle that might cause this.

03-14-2018, 01:18 PM	#5
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	As it should. If you leave it in park or in gear (AT or MT) then the driveshaft won't turn and it will maximize the RPM difference. It's 'around' 100 rpm, on mine I had to really get it spinning pretty good before it would engage. Although if you're not hearing any weird noises out of it from what you did, you probably don't have any issues with the G80 in turns. It's designed specifically to not engage unless there's a very significant wheel speed difference. As well as being prevented from engaging at all, regardless of wheelspin, over roughly 25 mph.

03-14-2018, 01:21 PM	#6
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	The flywheel has been cut from my g80, allowing it to engage whenever. I have no place to start then, trying to figure out this rumble.

03-14-2018, 01:42 PM	#7
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	There's still a smaller set of flyweights that kick in to engage it at the 100(ish) RPM difference. Wheel bearings?

03-14-2018, 01:49 PM	#8
2manyturbos Moderator Join Date: Mar 2003 Location: Monroe, OR USA	Just put your floor jack under either trailing arm and jack up one side of the rear axle. Make sure the jack is pointed in the same direction the car can roll. Start the car, put it in gear and ease your foot off the brake. After a couple of revolutions of the rear wheel that is up the G80 should lock and move the car forward. If it doesn't lock, something is broken or severely worn.

03-14-2018, 02:47 PM	#9
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	So you want me to let the car roll on the jack on one side? like a crutch or something ?

03-14-2018, 02:49 PM	#10
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	You should be able to do it by hand. Although in this case, we're not diagnosing if the G80 works, we're diagnosing a rumble in tight corners. The G80 isn't trying to kick in in a tight corner unless you're stomping on that gas pedal and spinning a tire.

03-14-2018, 02:59 PM	#11
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	It usually doesn't happen going through quicker, longer corners. Just tight ones. I recently had the thread about the vibrations in the drive-train. While I've basically sorted that, I'm curious if it's somehow related, even though I can't think of how it would be.

03-14-2018, 03:17 PM	#14
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	Yep, jack it up, leave it in gear so it doesn't spin the driveshaft, spin spin spin clunk. The junkyard G80 I got is apparently somewhat worn, it never really locked up all that solidly on the road, but you can really 100% feel it engage when spinning it by hand. Freely spinning clunk - can't budge it by hand. And again, if it's not making noises while you spin it, you should probably start looking elsewhere. Regardless of it finally engaging or not.

03-14-2018, 03:19 PM	#15
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	Alright guys, after I jacked up the car an hour ago, I went to drive it in my neighborhood making only right turns like a UPS truck, and found that it didn't happen a single time. I'm not saying I've got the magic touch, but maybe I do? If anyone needs my services, my rates are reasonable.

03-14-2018, 03:21 PM	#16
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	I'm obviously not convinced it's gone, but I'll wait and see. If it comes back, I'll test the g80 trying both methods.

03-14-2018, 08:38 PM	#18
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	Did you sell me that one? I forget. I sort of half thought I'd grabbed it from a junkyard around here. I did grab one from a fairly low mileage 940 a few years ago, I've just been too lazy to sap them.

03-14-2018, 08:46 PM	#19
2manyturbos Moderator Join Date: Mar 2003 Location: Monroe, OR USA	Yes. I sold it to you and once installed, you mentioned in another thread that you were underwhelmed with G80 locker performance. It made me examine their performance much closer before pulling them. I encountered a couple of them that had so little power transfer I didn't bother pulling them. I've probably pulled and sold 20+ so far.

03-14-2018, 08:52 PM	#20
JohnMc PV Abuser Join Date: May 2004 Location: St. Louis	The condition probably depends more on the way they were driven than the miles the car has.

03-15-2018, 08:15 PM	#22
LeedomtoFreedom Board Member Join Date: Oct 2017 Location: Chicago	I've made a liar out of myself. But in light of it's return, I had a thought. My shocks are completely blown, rusty, and 40 years old. Could the combination of the shocks not dampening the wheels when they try to stick in a turn, like wheel hop? Does this make sense ?