Locker advice

[jmbridges]

I am now almost 2 years into my 81 CJ7 rebuild, and it's coming along slowly but surely. Working on the rear axle now, installing moser one piece axles and I have started to think about the rear differential. I knew I was going to probably have to regear- original ratio was 2.73:1 - and with 33's that is not going to be drivable, unless the PO regeared when he put the 33s on. I didn't get to drive it long enough when I bought it to tell, though will see when I get in there.

Anyway, that got me to thinking about lockers as well.

I don't plan on rock crawling, just some routine off roading, maybe get into some mud now and then. This will also not be a daily driver, but i would like to take it out cruising from time to time.

From the research I have done on here and other places, it seems like a LSD might serve me best. I am thinking about the Detroit truetrac. Any thoughts about that vs a true locker? I don't think I want the expense and complexity of a selectable. Also, do I need both front and rear? Thanks much


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[jp360cj]

I've been very pleased with my Trutracs. You'll need a new carrier for the rear anyway, so that lowers the marginal cost of the TT.

As long as I keep the tires on the ground, they all pull. And it drives the same on the street.


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[Lumpy Grits]

A 'locker' and an LSD are not the same.
FWIW: I've been very happy with my front and rear DL's.
LG

 

[jmbridges]

Thanks for the replies! Yes, I know a locker and an LSD are different . That's part of the reason I need some advice - not sure which I need. Based on what I have read, LSD seems like it might be better for what I need, but I'm a newbie, so WTH do I know. Just wanted some real world advice on both. LG, how are the roads manners with the DLs? Is yours a DD? I take it from both your replies that having front and back is a good idea?

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[Lumpy Grits]

Yes a DD. The rear DL has a quirks for sure and after 25 plus years of have'n it in, I don't even think about it. In a tight turn, the DL 'drives' from the inside wheel so a 'chip' of the tire is kinda normal.
I do get reminded after my wife or kids drive it on the street....LOL
If I lived in snow country, I would have installed Power-Loc LSD, front and rear.
LG

 

[HackFabrication]

...not sure which I need. Based on what I have read, LSD seems like it might be better for what I need, but I'm a newbie, so WTH do I know. I take it from both your replies that having front and back is a good idea?

IMHO: On a Jeep CJ that will see no street snow/ice, the Detroit lockers would be fine. If you are willing to accept the 'quirks' that LG stated. If you put a Detroit locker in the front, don't run on hard pavement with the front hubs locked.

I run ARB's front/rear in my 76 CJ5, because I want the road manners of open differentials, with the capability to fully lock either front, rear, or both when necessary.

The one piece axles are a definite 'must'. I have Moser's in my AMC20. I would also recommend welding the axle tubes to the housing.

 

[elkgroveguy]

If money is no object I like Electric lockers front and rear.
When on a budget I go (lunch box locker in the front) True trac in the rear.
I have had both and for those are the best for street manners in my opinion.

 

[gr8dain]

Aorry to jump in with a question, but I have a lunch box locker and wondered if I should put it in the rear or not. As a DD, is that going to be bad? A lot of clicking as I drive and chirping around corners? Any other drawbacks?

If I just have the one locker, and it is a lunchbox, should it go in the front? I do hit the trails a couple of times a year and run blues but want to do more rocks. AND still use it as a DD. Thanks for your thoughts.

 

[Posi]

Do you have stock 2 piece rear shafts?
If so I would install the locker in the front.
If the answer is no, I would install it in the rear.
When you climb offroad all the weight is in the rear where a locker would help.
You have a long wheel base Jeep your not going to feel much.
My 77 CJ7 has spartans front and rear and the only time I feel the rear is backing up while turning sharp and once in awhile slowly turning going forward.
Although a lot of highway driving, I ran it from Colorado Springs to Ouray (about 5.5 hours) last year without any locker issues. I will again be running it from Colorado Springs to Moab next month.
I feel the Detroit more in my short nose 71, but still not bad enough that I would change it.

 

[gr8dain]

Thanks. I have 1 piece axle shafts in the rear. So I will continue with my plan of throwing it in the rear.

 

[Lumpy Grits]

IMHO: If you put a Detroit locker in the front, don't run on hard pavement with the front hubs locked.
The one piece axles are a definite 'must'. I have Moser's in my AMC20. I would also recommend welding the axle tubes to the housing.

There is no issue with the hubs engaged on hard surface with a true DL in the front, if there's no power to the front DS.
Same as flat towing with a DL in the rear.


'Lunch-box lockers have the same 'manners' as a DL does on the street.
It's just that they ain't anywhere near as strong as a true DL.
LG

 

[007]

I'll complicate this a bit...

Those of us with a Quadratrac should be fine using Truetrac's front and rear, on-road as we have "slip" in the TC (provided case is not in e-drive).

 

[elkgroveguy]

I can tell you that in my bronco I currently have a lunchbox locker in the front and open in the rear.
I wish I would have put the locker in the rear.
I dont really like the front locked in the snow which is where I do a lot a wheeling.
For my CJ Im doing the opposite and going locker in the rear.
CJ will be more for rocks!

 

[jmbridges]

Thanks for the advice all, gives me something to think about. I still think an LSD is probably going to work best for me. We don't get much snow here in Alabama, but when we do, it is a cluster. Would like to be able to get out in the jeep and get my milk and bread . Who knows, I may get into the diff and find a locker and new gears already in there. I hope to open up the rear this weekend, so if I see something that doesn't look stock, I'll post some pics and maybe someone can tell me what I have!


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[Lumpy Grits]

I can tell you that in my bronco I currently have a lunchbox locker in the front and open in the rear.
I wish I would have put the locker in the rear.
I dont really like the front locked in the snow which is where I do a lot a wheeling.
For my CJ Im doing the opposite and going locker in the rear.
CJ will be more for rocks!

In snow country(I'm from Colorado)I suggest a LSD and not a true 'locker'.
LG

 

[jp360cj]

Thanks for the advice all, gives me something to think about. I still think an LSD is probably going to work best for me. We don't get much snow here in Alabama, but when we do, it is a cluster. Would like to be able to get out in the jeep and get my milk and bread . Who knows, I may get into the diff and find a locker and new gears already in there. I hope to open up the rear this weekend, so if I see something that doesn't look stock, I'll post some pics and maybe someone can tell me what I have!


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I though milk sandwiches were just an NC thing!

While you have the rear opened, look for the gear ratio/tooth count stamped into the outer face of the ring gear to verify ratio. Much easier than counting all those teeth.

 

[jmbridges]

I though milk sandwiches were just an NC thing!

While you have the rear opened, look for the gear ratio/tooth count stamped into the outer face of the ring gear to verify ratio. Much easier than counting all those teeth.

So after much cursing and gnashing of teeth, I was finally able to get into the rear diff today. Unfortunately, I did not see the ratio stamped on the ring gear. The only thing I saw stamped on the gear looked like "154". See pics below.

I think this is probably stock and is supposed to be 2.73:1 ratio. I didn't see an easy way to count the teeth without taking everything out, though eventually I will be taking it out. Anyone got any ideas if this is the stock ring and pinion?

Along those lines, I am thinking about 4.10 gears as a replacement. Thoughts on that ratio? I have 33s, rebuilding my 258, have a new 4.0 head for it and planning to add fuel injection. Thanks.

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[Torxhead]

In my opinion 4:10 gears without an overdrive, will put your highway rpms a bit on the high side, even with a 33" tire. On the trail, they work quite well. I highway cruise at around 60 mph at 3000 rpm. That is with 28 p.s.i. in the tires for a fairly decent ride.

 

[Belizean]

Thanks. I have 1 piece axle shafts in the rear. So I will continue with my plan of throwing it in the rear.

I have a Lock Right locker in the rear and is pretty well behaved on the street.

 

[gr8dain]

I have a Lock Right locker in the rear and is pretty well behaved on the street.

Good to hear. Thanks.