The Stupid Axle Questions Thread

[98chevy2500SS]

I think he's saying on the 9.5" axle:

Only G80 option was offered
LSD was never offered

At least that's what I understood.

Re-read his post closer and now I see what he's asking. I'm not sure if I have ever seen a 9.5" axle without a G80, hopefully there are others that have come across one, maybe @someotherguy or @Z71Hobbs have seen one?

 

[stutaeng]

Re-read his post closer and now I see what he's asking. I'm not sure if I have ever seen a 9.5" axle without a G80, hopefully there are others that have come across one, maybe @someotherguy or @Z71Hobbs have seen one?

Yeah, I was also trying to remember. Those old Eaton videos that I've posted before are square body generation trucks with the G80, and I'm certain that's true of GMT 400s also. At least on the later GMT 400, the only differential traction aid was the G80, nothing else.

LSD I thought was a car thing...

 

[Ugly Duck]

I think he's saying on the 9.5" axle:

Only G80 option was offered
LSD was never offered

At least that's what I understood.

That's what I meant, yes. My truck has a 9.5 and all I want to do is to replace the diff, not the whole axle, with something from the JY with an LSD (and not the G80).

I've modded the Eaton locker in older Volvos so that the wheel speed governer is disabled, enabling locking at any speed, but this probably doesn't improve the lifespan very much. It didn't impact road manners in any way, it just locked up any time I asked it to. Not sure if this is what I want in the truck or not, but if a better option were available I'd go for it.

 

[stutaeng]

That's what I meant, yes. My truck has a 9.5 and all I want to do is to replace the diff, not the whole axle, with something from the JY with an LSD (and not the G80).

You won't find a LSD at the junkyard, as they were not offered from the factory. Unless you somehow find one that someone installed aftermarket on. Good luck on that.

Here's one that looks like will work for the 14 bolt 9.5" semifloat axle:

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt

914A538 Detroit Truetrac Limited Slip GM 9.5" 14 Bolt<br /> APPLICATION: GM 9.5" 14 Bolt<br /> AXLE PLACEMENT: REAR<br /> AXLE SPLINE COUNT:33<br /> SPLINE DIAMETER:1.37"<br /> COVER: 14 BOLT <br /> GEAR RATIO: ALL RATIOS<br /> MODEL:GM 9.5" <br /> RING GEAR DIAMETER:9.5" <br /> NOTES: GM 9.5"...

www.drivetrainamerica.com

Do some research on this model here. Some folks have provided feedback. I don't know anything about it. All my trucks have the G80 in 10 bolt, 14 bolt 9.5" and 10.5".

 

[Ugly Duck]

Yeah, the Truetrac is a really nice piece, I've owned a couple of them in cars. I don't know why someone would install one in an off-road truck though. Mine's 99.99% street driven so it would be a fine option if I go aftermarket. I guess I'll go to the JY and will mod a stock diff first & see how long it lasts, or if it sends me off into a ditch LOL!

Just wondering if anyone else has experimented with modifying the G80 here?

 

[stutaeng]

Um, it looks like they actually have rebuild kit for the 9.5" G80: https://www.betperformance.com/prod...4-bolt-late-differential-complete-clutch-kit/

 

[kennythewelder]

I installed a trutrack in my truck last year. I love it.

 

[Ugly Duck]

Um, it looks like they actually have rebuild kit for the 9.5" G80: https://www.betperformance.com/prod...4-bolt-late-differential-complete-clutch-kit/

GM G80 Gov-Lock 8.5" 8.6" 9.5" 10 & 14 Bolt Differential Latching Governor Kit - BET Performance & Engineering

Late model GM latching governor kit

www.betperformance.com

I believe the latching axle (on the left) is the part that breaks, normally. Strips the teeth off the geared end of the axle when one wheel is spinning and wheel speed drops low enough to lock the diff.

 

[stutaeng]

GM G80 Gov-Lock 8.5" 8.6" 9.5" 10 & 14 Bolt Differential Latching Governor Kit - BET Performance & Engineering

Late model GM latching governor kit

www.betperformance.com

I believe the latching axle (on the left) is the part that breaks, normally. Strips the teeth off the geared end of the axle when one wheel is spinning and wheel speed drops low enough to lock the diff.

You said you didn't know if yours is not working? Was it working before? You have the correct fluid? IIRC, no friction modifiers on the G80? You need to remove your differential cover and see what the internals look like. Are you on stock tires? What's the use for the truck? Light off-road?

I don't know of anyone modifying their G80, unless you are asking about fixing it up. If it's only the governor that broke and everything else is okay, that seems like an easy fix.

Why is the Tru-trac not a good idea for off-road use? I hear they are great all-around. I couldn't remember if that's what @kennythewelder had installed in his truck. I believe the only downside is you have to "fool" it by tapping on the brakes if one of the rear wheels come off the ground and get it to engage? I wouldn't really think that's a downside myself, just learn to operate it. Big advantage is no air lines, compressors, electrical and other stuff to worry about.

I don't know much of else out there for the GM 9.5" maybe ARB air locker? Lot's of offerings for the 10.5" though:

14 Bolt Locker Options

A 14 bolt rear axle is one of the simplest and cheapest strength upgrades you can do when you need a strong rear end. Because they're cheap and strong, some of the options are a little different than other axles, and usually those options are also more budget-friendly. This is the best source...

www.roundforge.com

 

[Ugly Duck]

You said you didn't know if yours is not working? Was it working before? You have the correct fluid? IIRC, no friction modifiers on the G80? You need to remove your differential cover and see what the internals look like. Are you on stock tires? What's the use for the truck? Light off-road?

I don't know of anyone modifying their G80, unless you are asking about fixing it up. If it's only the governor that broke and everything else is okay, that seems like an easy fix.

Why is the Tru-trac not a good idea for off-road use? I hear they are great all-around. I couldn't remember if that's what @kennythewelder had installed in his truck. I believe the only downside is you have to "fool" it by tapping on the brakes if one of the rear wheels come off the ground and get it to engage? I wouldn't really think that's a downside myself, just learn to operate it. Big advantage is no air lines, compressors, electrical and other stuff to worry about.

I don't know much of else out there for the GM 9.5" maybe ARB air locker? Lot's of offerings for the 10.5" though:

14 Bolt Locker Options

A 14 bolt rear axle is one of the simplest and cheapest strength upgrades you can do when you need a strong rear end. Because they're cheap and strong, some of the options are a little different than other axles, and usually those options are also more budget-friendly. This is the best source...

www.roundforge.com

The truck is new to me, and it wasn't working when I got it. The PO got it fairly recently before I bought it (lots of issues that I wasn't afraid to tackle) and one of the things he said (and that I verified) is that there are new shafts in the axle for some reason. One was bent? Anyway, the guy put new shafts in and probably either blew up or removed the G80 and replaced it with an open diff. I don't know if it's working or not because it might be working... in someone else's truck. I haven't pulled the cover yet.

Yes if the parts are available (which they aren't for a Dana 30 version in the Volvos, and RWD Volvo guys are notoriously cheap so probably wouldn't fix them anyway), it's an easy fix. What we were doing back in the day was to clip off the weight on the locking pawl, which normally pulls away from the flyweights and disables the locking feature above 25 mph or whatever speed it is. If I remember correctly the unit normally shatters when a wheel is spinning hard at speeds above this, and then slows down to suddenly lock up. If the diff is allowed to lock no matter the wheel speed the theory says it's easier on the mechanism because the "loose" wheel never gets a chance to build up a head of steam.

Currently it's on GMT-900 17" wheels and tires, I'll go back to the 16s when I get some rubber for them. 85% pavement/snow, 14% gravel, 1% superduperlight offroad. It's the snow/ice where I want the grip.

My experience with a True-Trac isn't offroad, but I know they rely on torque to drive the helical gears into the cases & "lock" the diff. Tapping the brakes to put torque into them brakes the fast wheel but also brakes the slow wheel, and isn't the most efficient way to go. They are magnificent on a road course though! A clutch or cone style diff has more initial preload so I *imagine* they'd be preferred offroad, with the ultimate being something that's fully locked up under power. Again, I'm not really an offroad guy so WDIK? If I were to choose an aftermarket diff for my application, it would be a True-Trac, but that's for the smooth engagement on ice & snow as much as anything. A modded G80 is all or nothing, but it wasn't awful in my wagon.