Is a Detroit Locker too much for the street?

Haulin' 8.1 · August 20, 2005

Hey guys I'm looking for some experience opinions here. My truck is a '01 8.1/Allison powered SBCC 4x4 with 265's. I'm planning on gearing down to 4.56's in the near future and I'm trying to decide if I should retain the factory G80 locking differential or swap in a detroit locker case when I'm in there. (I know the case would have to be swapped as well, that's not an issue). What I'm concerned about is excessive noise and wet road drivability. This truck is used as daily transportation to and from work and to haul the family around town when shopping or traveling etc. I tow trailers of all sizes and wieghts from time to time. It is off roaded rarely at low speeds.

I know I sound like I should just retain the factory diff but I can pick up a low mileage 4.56 set up with a Detroit Locker at a good price so I'm wondering if it would be a good thing to get or would I end up regretting it.

I could handle a faint clicking when turning tight but if they're louder than normal conversation or the radio then I'd pass. Would I hear it over the Magnaflow?

Just the other day I had some bozo pull out in front of me on a wet highway in a lifted Z71 then fish tail back and forth trying to get going. I started coasting the second he rolled out but when I was about to have to hit the brakes or hit the gas and pass I hit the gas. My 8.1 has plenty of get up and go so as I'm going around at about 55 the rear end starts going left, I was able to let up and avoid a spin but that made me wonder about how safe a locker would be in this truck. The factory diff is supposed to unlock at 25+ and either mine stuck or both wheels were over powered equally that day without the diff. Wouldn't a Full locker make wet weather driving more of a challenge? Is it something that is easy to control as long as you're not overdoing the throttle or is it something you have to be very weary of to avoid fish-tailing at any time you're gassing it on the wet?

Thanks,

Vernon

BDZ71 · August 20, 2005

If your truck is not offroad allot Id stay no to the detroit. Anytime you are on the gas it is locked. In turns wet dry it does not matter.

A nice Eaton or Auburn pro would probably suite you best. Or even a selectible locker like the eaton Elocker would be nice but more money.

I would almost say keep the G80 but they seem to not take to aftermarket ring and pinion ratios to well.

Haulin' 8.1 · August 21, 2005

Thanks for you input, it's much appreciated. So it seems you're saying the Detroit would be more trouble on the road than I'm looking for but then the G80 might not be up to the 4.56's either.

What happens to the G80, does it break often or just not work right after lower gears?

Vernon

BDZ71 · August 21, 2005

Thanks for you input, it's much appreciated. So it seems you're saying the Detroit would be more trouble on the road than I'm looking for but then the G80 might not be up to the 4.56's either.

What happens to the G80, does it break often or just not work right after lower gears?

Vernon

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Well I use to have pictures but I cant find them. Not in all cases but with the torque of the lower gears there are 2 pushrod type things in the G80 that engadge. One option would be that they break. Other times I have seen the G80's housing itself crack (if you catch it soon enough) if not that crack can completely "grenade" taking with it the ring and pinion.

Some people never have a problem, some do. It being a G80 in a 11.5" rearend like you have with the 8.1 it is a stronger unit than the 8.5" or 9.5" rears but to tell you the truth, if I was me and I was already digging into the rearend id opt to get it out just incase.

As for the Detroit. For a truck that does not see much offroad use id say to stay away. The way it works is that it is 100% locked ANY time torque is put to the carrier (every time you push the gas) No matter how fast your going or if your turnin or not.

For someone that does not do alot of offroading.. every time say your in a turn, if your on the gas the rear is locked.. wearing down the inside tire, and pushing the front of the truck "straight". Driving characteristics change here.

Also if your ever in snow or ice this could be more dangerous b/c one tire would have loss of traction in turns from the simple fact that each side would be turning at the same rate even though the inside tire would be going a less of a distance.

See what im saying?

Personally if I knew my truck was not going to be carrying me threw some thick mud or over some nice obstacles I would not want a detroit.

Can it be done... yes absolutely people do it everyday. But its just not for everyone IMO.

On the other hand Eaton or eaton Elocker, Auburn pro and a few others are nice replacement units for the G80. That have alot better roadmanners

Haulin' 8.1 · August 21, 2005

Great, thanks for your time. I guess I'll pass on the Detroit Locker and look for a good deal on a limited slip.

Vernon

FloridaZ · August 23, 2005

Great, thanks for your time. I guess I'll pass on the Detroit Locker and look for a good deal on a limited slip.

Vernon

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Ditto what everybody is saying about the Detroit. Depending on how sharp you are turning it is pretty loud sometimes. The G80 should serve you well.

vhato · August 24, 2005

The problems with the G80 are only related to the 8.625" 10-bolt axles. You have an 11.50" 14-Bolt axle so strength is a mute point. You won't damage that G80 before you blow something else up first.

I have installed my share of Detroits. IMO, I would only own one in a an Off-Road rig that needs the strength. The notchiness of the whole truck while turning really bothers me on a daily driver. The 14-bolt G80 is a tad notchy while taking right turns, it is a whole lot more with the Detroit.

The G80 does unlock at ~25 MPH, however it is not an Open Differential. It contains 4 Carbon Fiber Clutches between the carrier and spider gears, so when the Locker is unlocked, it functions as a Limited Slip. That is why you still spun your tires at higher speeds.

Haulin' 8.1 · August 24, 2005

Well I called my gear installer of choice today (one of the best shops in Houston) and got a quote on a complete job. Using my G80 which he likes and high quality new gear sets with fresh carrier bearings in back and seals all around would liten my wallet to the tune of $1622. Then I'd still have to pay the stealership to reflash my electronics due to the Allison.

I don't think I'll be having him do that anytime soon. That's out of my league. It's something I can do myself but I'd take a couple of days at least on each end and have to worry about doing it just right a lot more than I'm comfortable with. But I guess I'll have to tough it out.

Thanks for the extra information guys, it does make my choices easier to make.

Vernon

vhato · August 24, 2005

Well I called my gear installer of choice today (one of the best shops in Houston) and got a quote on a complete job. Using my G80 which he likes and high quality new gear sets with fresh carrier bearings in back and seals all around would liten my wallet to the tune of $1622. Then I'd still have to pay the stealership to reflash my electronics due to the Allison.

I don't think I'll be having him do that anytime soon. That's out of my league. It's something I can do myself but I'd take a couple of days at least on each end and have to worry about doing it just right a lot more than I'm comfortable with. But I guess I'll have to tough it out.

Thanks for the extra information, it does make my choices easier to make.

Vernon

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Ya,

The 11.50" rear gears at 4.56 are RARE and 4.88, 5.13+ are practically dream sets. The front 9.25" are available everywhere in most ratios since GM uses it with the 9.5" 14-bolt, 10.50" 14-bolt and 11.50" 14-bolt.

The Full Floating design of your rear axle does add to the cost. You probably have $550.00 just in front/rear gear costs alone. Rear bearings are probably $200, front bearings are $150.00 and $75 in fluid. That is almost $1,000.00 before labor. I would say those prices with $700 labor is about right for those big heavy axles in a 4WD HD w/Duramax 6000 or Vortec 8100.

A set of 4.56's on 245/75r16's would be SWEET to pull with and burn down. I see Ford offers 4.56's on their F-350 SD in LIMITED configurations.

I wrote a tech article on rear axles at FSC. Since 95% of trucks are 1500's I wrote it for semi-floating axles. The Full Floaters are almost the same. Finding Pinion depth and backlash are bascially the same. To see what you are getting into view my article at:

http://www.fullsizechevy.com/fscu/axletech/