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7.5 Carriers for Open to L/S Swap


SuperRob

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Hey guys,

I find myself out of work AGAIN...damn oil company shut the rigs down (its only temporary, I'll find another rig so no sweat...but still!) and I'm back at my parents house in Kitimat looking thru the boneyard that we seem to have built up here. My brothers Ranger had a 7.5 3L73 rear end in it, and mine is open. I'm looking into putting the L/S into my truck. Now heres the dilemma:

L/S diff - Has no brakes, and pinion is leaking pretty bad. Gears are in pretty nice shape. Diff was full of water until yesterday when I put it on axle stands and it all drained out the pinion seal. However, no rust. No idea how good the axle seals are.

Open Diff - Has brakes, although havent looked at them in about a year, they only have about 30000 km on them but I will inspect them this weekend. Gears work fine...the other ones look a little better, but not enough to make it a factor in my decision. All seals are in good shape.

Should I be looking into pulling the carrier from the LS diff and swapping it to the open diff, or should I be rebuilding the LS axle.

I heard that I can just pull the ring gears out of both, swap the carrier over, and then reinstall the ring gear with the new carrier using the original shims from the Open diff. It was explained to me that the shims are used to make up for differences in Diff housing castings. NOT for differences in carriers, because the carriers are all machined the same.

Meaning, that as long as Ikeep the original shims with the original AXLE then the carrier swap wont matter.

Who can speak to this? Confirm or deny? Advice?

Also, I'm interested in rebuilding this LS but only if necessary, can you tell me the specs on the thickness of the clutch plates and when they should be replaced? or is there another way to tell?

Thanks as always!
 


Hahnsb2

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Carrier swaps are a bitch, especialy if the axle is in the rig, mine took about 8 hours but I had to do some extra stuff like install a locker and grind the ring gear to get the crosspin in. I did the opposite of what you did, I put an open carrier in my rearend so I could use my Lock Right locker. I used the shims from the open carrier when I put it in my rig, backlash was about .002 too much but I ran with it, its been 7000-8000 miles now and my gears are just fine. Getting the ring gear on and off and torqueing down the bolts is probably the hardest part.
 

rickcdewitt

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i'de check that the pinion yoke and bearings on the open diff are tight.then measure the backlash on the gearset with a dial indicator and record it.it should be .008-.015" or something like that.put the ring gear from the open diff on the trac-lok carrier,and install it.between the two sets of carrier bearing spacers you should be able to put backlash back where it was.if you have a press and a bearing knife its not too hard too put new bearings and seals in the whole axle.you might want the crush sleeve eliminator kit and you will need a dial type inch pound toque wrench if you pull out the pinion though.with the used gear set remember to put backlash back where it was.
 

rickcdewitt

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oh by the way hahnsb2,you can buy a buy a modified cross pin with a notch in it so you dont need to remove it when pulling the axleshafts.thats what i did for my 4.56's and 4.10 gears-no grinding on gears,put the pin in then bolt on the ring gear.
 

SuperRob

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Well I just found out that I dont need to remove the pinion in order to replace that seal....(Never done this stuff before so I'm learning as I go)

But I think that what I'm going to do is do all the seals and the brakes on the LS axle and just swap the whole damn thing in.

Seems to be the easiest, and that way I dont have to piss around with the whole gearset.

ALTHOUGH I still would like to know how to tell how much life is left in this LS clutch pack....any ideas?

Thanks for the responses so far.

Rob
 

rickcdewitt

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be careful replacing the pinion seal.when you take the pinion nut off you will need to make sure the crush sleeve dosen't get squashed further when it goes back on so the preload on the pinion bearings doesn't become too tight.you'll need a inch pound torque wrench to check bearing preload.thats the only way to retorque the pinion nut without a crush sleeve eliminator set.
 

MAKG

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I'd be concerned that the hosed pinion seal is indicating hosed pinion bearings. If that's the case, this rear end won't last long.

Whatever you do, check the gear contact pattern before you put the diff cover on. That will tell you BEFORE you hose the gearset whether it's going to survive its first drive or not.

LS clutch packs have a "breakaway torque" spec. Put the truck in neutral in 2WD (or neutral transfer case if you have that), and lift one rear wheel off the ground. Put a torque wrench on one lugnut and measure how much torque it takes to turn the wheel. You're supposed to center the wrench on the wheel, so this is only approximate, but I believe the spec is 25 ft-lbs. If it's less than that, you need new clutches.
 
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Hahnsb2

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oh by the way hahnsb2,you can buy a buy a modified cross pin with a notch in it so you dont need to remove it when pulling the axleshafts.thats what i did for my 4.56's and 4.10 gears-no grinding on gears,put the pin in then bolt on the ring gear.
I know... 3.73 and 4.10 axles came with them. I couldn't use the notched one with the locker because it wouldn't pull out far enough for me to move the spacers inwards to get the c-clips on the axles, so I said **** it and I ground the ring gear down and put the stronger full crosspin in that came with my lock-right.
 

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The clutches wear on l/s packs and need to be re-shimmed occasionally. easiest way to do it is to shim the pack until the cross-pin will only just go back in. that's not the recommended method but it's the method I've been happiest with.
 

SuperRob

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Can anyone else confirm for me the method and values used to determine the life of a Trac-Loc?

MAKG says 25 ft-lbs and it should break free....but that was based on recollection only....Haynes doesnt mention it, neither does the online website that I 'DO'...nt have access to.


Thanks for the advice....

Rob
 

Sasquatch_Ryda

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Hey Rob,

I'd just swap the open carrier out for the limited slip carrier. Reuse the stock shims and it should come out pretty close if not the same. Get some gear marking paint and go it. That way you don't have to worry about the pinion preload. Let me know if you need any help, i've done a few diffs myself.
 

SuperRob

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Hey Ryan.

I already got all the parts I needed to 'refresh' the LS axle. New axle seals and pinion seal. Gonna do brakes on it too while its sitting on the axle stands....Swapping out the axles is piss all and I need to be able to leave town at a moments notice due to work....so the truck has to stay running....and the way I seem to work on things, it'd just take longer to change out carriers and check everything.

Thanks tho....

still need to know about those clutch plates though!!!

Cheers all!
 

SuperRob

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Got the answers to some of my questions....

Apparently the glue used on the clutch plates is water based, and the fact that the diff had some water in it is bad news.

Also, apparently they need about 40 Ft Lbs to break the trac loc free....I can do it by hand on the axles with no lever....me thinks they is shot.

So I got new clutches coming.
 

rickcdewitt

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watch out if you take off the pinion nut.going back on (you should use a new one or locktite) you can crush the crush sleeve too far and over tighten the pinion bearings.you should have an inch pound wrench to check pinion bearing preload as you tighten the nut and check the preload before taking the nut off so you can torque it to the same value later.if you go too far you need a new crush sleeve.
 

canoeman1972

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Where did u get new clutches for your trac loc? I need a new set
 

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