D30 Carrier Break and Locker

[89 MJ]

Kinda MJ related, kinda not. 
 

Come spring, I am going to be rehearing my Eagle. It has a D30 front. I have read conflicting information on where the carrier break is on a D30. I have read that there is one carrier for 2.35 gears, one for 2.63 to 3.54 gears (the one I have) and one for 3.73 and up. I have also read that there isn’t another carrier—there is just the 2.35 and the 2.73+ carrier. 
Does anyone know which is the case? 

Disclaimer—I know regrading a D30 sounds like a waste, but because the Eagle is IFS, I can’t just install and XJ axle. 
 

Now for my locker question. I know that the G80 isn’t the best locker, but for my application it would be all that I need (the car will see some snow and dirt roads, nothing too crazy). Does anyone have any experience with the Volvo D30 G80 locker in their front D30? The only info I have found is that it can be done. Do I need the whole carrier out of the Volvo?

 

Thanks all!

[ghetdjc320]

The D30 carrier break is 3.73 and numerically higher. I’m 100% positive on that. 

[Eagle]

1 hour ago, ghetdjc320 said:

The D30 carrier break is 3.73 and numerically higher. I’m 100% positive on that. 

 

Confirmed. For the Dana 30, the carriers used are divided into 3.54 and lower numerically, and 3.73 and higher numerically. This is usually referred to as the “carrier break.

[89 MJ]

8 hours ago, ghetdjc320 said:

The D30 carrier break is 3.73 and numerically higher. I’m 100% positive on that. 

 

6 hours ago, Eagle said:

 

Confirmed. For the Dana 30, the carriers used are divided into 3.54 and lower numerically, and 3.73 and higher numerically. This is usually referred to as the “carrier break.

Thanks guys!

[Tex06]

This G80 isn't the same as the GM "Gov-bomb" G-80 by chance is it?  Limited slip

[ghetdjc320]

13 minutes ago, Tex06 said:

This G80 isn't the same as the GM "Gov-bomb" G-80 by chance is it?  Limited slip

I believe it is. Made by Eaton probably to GM spec. It reminds me a bit of the Auburn lockers. Still uses clutch packs. 

[Tex06]

14 minutes ago, ghetdjc320 said:

I believe it is. Made by Eaton probably to GM spec. It reminds me a bit of the Auburn lockers. Still uses clutch packs. 

Oof. Best of luck to the OP. I think I'd go for a Detroit TrueTrac for his application, they're under $500 and an easy drop-in. 

[ghetdjc320]

4 minutes ago, Tex06 said:

Oof. Best of luck to the OP. I think I'd go for a Detroit TrueTrac for his application, they're under $500 and an easy drop-in. 

Agreed. I was watching the manufacturer videos on that locker and they look quite problematic. A simple Aussie locker would work well also

[Eagle]

2 hours ago, ghetdjc320 said:

I believe it is. Made by Eaton probably to GM spec. It reminds me a bit of the Auburn lockers. Still uses clutch packs. 

 

The Auburns are limited slips, and use clutches. The G80 is a locker. I don't think it uses clutches.

 

https://www.topspeed.com/cars/car-news/deep-dive-general-motors-g80-locking-rear-differential-ar169064.html

[ghetdjc320]

27 minutes ago, Eagle said:

 

The Auburns are limited slips, and use clutches. The G80 is a locker. I don't think it uses clutches.

 

https://www.topspeed.com/cars/car-news/deep-dive-general-motors-g80-locking-rear-differential-ar169064.html

If the Volvo unit is the Gov-Loc it uses clutches. In that sense it is similar to the original Auburn select-a-loc which used a cone shaped clutch disk setup to “lock”. The fact is that the G80 requires “slip” in order to function. The auburn can be engaged with a switch so no “slip” is required. In that sense the Auburn functions more like a locker (but as a limited slip when the electromagnet is not engaged). Ultimately it looks like both rely on clutch packs to maintain friction “lock” even though that friction is assisted by another device. 

I’d be curious to know how the Volvo unit works in real world Jeeping scenarios though. I’ve run truetrac’s, aussies and ARB’s and the ARB has been the best so far but comes with quite a price tag and a more complex install. 
 

The one drawback I see to the G80 is the way it engages. Seems like a recipe for disaster putting all that stress on those small parts. Maybe if a tire slips on some ice or wet leaves but I can’t image the violent engagement that thing would have if you’re out mudding at high rpm’s. Guess that’s why it won’t engage over 20mph wheel speed. It’s been a few years since I went mudding but I do seem to recall wheel speed was pretty high to keep from getting stuck. In those scenarios it may not even engage. Seems like a unit from a Volvo also wouldn’t be up to the amount of inertia it would be subjected to under a built Jeep out crawling

[89 MJ]

The main reason that I am looking at the G80 vs an Auburn, Detroit Tru-Trac, and others is because it would be going in the front of my Eagle. That car will only every really see snow and maybe sand or small rocks depending on where I go to school. I have no desire to go mudding. I just thought it might be a cheap option worth looking into. 

[ghetdjc320]

34 minutes ago, 89 MJ said:

The main reason that I am looking at the G80 vs an Auburn, Detroit Tru-Trac, and others is because it would be going in the front of my Eagle. That car will only every really see snow and maybe sand or small rocks depending on where I go to school. I have no desire to go mudding. I just thought it might be a cheap option worth looking into. 

Ahh that makes sense. Though it was going in an MJ. I would think it should be fine for a car though May have some quirks being used in the front axle.

[Andy in Pa]

Definitely make sure the D30 in your Eagle is a HPD30 and not a LPD30.  I looked into this a few years ago, and it seems like it was not the same as most D30 diff's that came in MJ's and XJ's.  It may be a LPD30 like the TJ's and later XJ's had.

[ghetdjc320]

18 minutes ago, Andy in Pa said:

Definitely make sure the D30 in your Eagle is a HPD30 and not a LPD30.  I looked into this a few years ago, and it seems like it was not the same as most D30 diff's that came in MJ's and XJ's.  It may be a LPD30 like the TJ's and later XJ's had.

It may be a LP D30 but the actual carriers are the same. Only the ring and pinions are different. 

[89 MJ]

7 hours ago, Andy in Pa said:

Definitely make sure the D30 in your Eagle is a HPD30 and not a LPD30.  I looked into this a few years ago, and it seems like it was not the same as most D30 diff's that came in MJ's and XJ's.  It may be a LPD30 like the TJ's and later XJ's had.

Good call. Thank you. 

[89 MJ]

9 hours ago, ghetdjc320 said:

Ahh that makes sense. Though it was going in an MJ. I would think it should be fine for a car though May have some quirks being used in the front axle.

I’m curious about the quirks too, but I haven’t found anyone who has actually done it, I just know that it can be done. 

[Eagle]

13 hours ago, ghetdjc320 said:

If the Volvo unit is the Gov-Loc it uses clutches. In that sense it is similar to the original Auburn select-a-loc which used a cone shaped clutch disk setup to “lock”. The fact is that the G80 requires “slip” in order to function. The auburn can be engaged with a switch so no “slip” is required. In that sense the Auburn functions more like a locker (but as a limited slip when the electromagnet is not engaged). Ultimately it looks like both rely on clutch packs to maintain friction “lock” even though that friction is assisted by another device.

 

Auburn offers three different types of replacement differential. The one we used to see when I was active in NAXJA-NAC was the "Grip-N-Loc," which is a standard, clutch type limited slip that uses a cone-shaped clutch pack.

 

Then there are two flavors of "Select-A-Loc." One runs normally as a clutch-type limited slip, and has an electrically-activated locker function for more positive locking. The other is an electrically-activated locker that is an open differential, rather than a limited slip, when not locked by the electrically activated locker. The lockers in both Select-A-Loc units are mechanical, not clutch operated.

 

For a D30 front axle, I would go with a Detroit True-Trac.

[derf]

I'd echo the recommendation for a TrueTrac.  I had one in the front if my XJ and it did great all around.  Good on dry pavement and in the snow.

[ghetdjc320]

9 hours ago, Eagle said:

The lockers in both Select-A-Loc units are mechanical, not clutch operated.

First off, apologies to the OP for this side topic lol.
 

@Eagle Both Auburn units use clutches and even require limited slip additive. This includes both the open/locked and the lsd/locked models. On the original select a loc (formerly known as the infamous Ected), there is no actual “locking” gear mechanism like you would find on a full case selectable aftermarket locker such as an ARB. The actual “locking” friction comes from the clutch plates. The electromagnet in the original Auburn select a trac is a way of applying extra pressure to the clutch packs on-demand. Here is an explanation directly from Auburn: 

 

The center block also applies force to the opposite side gear (6) to compress the clutch pack (7) and provides the vehicle with a solid axle assembly that transfers 100% of the torque to both wheels, 

 

Taken from this source: https://auburngeardiffs.com/select-a-loc-ltd-slip-to-lock/

 

And here is a picture. Notice the large clutch pack (figure 7) that rides just under the spider gear.

 

I have not dug into the Gov-Loc to see exactly how their clutch packs are used but I wonder if it’s not similar in the sense that they increase the pressure on the clutch packs in order to “lock” the diff. Obviously the method of activation is different. Furthermore, the gov-loc isn’t actually a locker in the sense that it requires slip to activate. It’s more like a “very limited slip”. The torque bias after engagement seems to be pretty good though. 
 

 

[ghetdjc320]

9 hours ago, 89 MJ said:

Good call. Thank you. 

Keep in mind that there is no difference between an HP and LP D30 carrier. The difference is in the gearset

[89 MJ]

18 hours ago, derf said:

I'd echo the recommendation for a TrueTrac.  I had one in the front if my XJ and it did great all around.  Good on dry pavement and in the snow.

I’ll have to look into those some. 
 

 

16 hours ago, ghetdjc320 said:

First off, apologies to the OP for this side topic lol.

Don’t worry about it. I love learning this stuff. 

[PIKE]

Another vote for a TrueTrac in the front. I have two Jeeps and a Ford F350 all with TrueTracs in the front. They are seamless on the road but really do the job when you need them. No special maintenance either. Just use gear lube with no limited slip additive for better lock up.

 

As far as the Gov Lock goes if you see one run away as fast as you can. I had a 1977 Chevy pickup with one in the back. What a turd. What no one has touched on yet is that after it engages it is designed to disengage once the tires are both rotating at the same speed. So you get about one second of lock up. Then if one wheel is spinning again it will lock up again then disengage when both tires are spinning. You get this jerky motion then and it will self destruct with any heavy usage. Ask me how I know that haha.