Question on differentials?

Looking at changing my rear diff to LS type. A few questions since I only know basics and have never changed a gear set.
1) when they advertise a diff and say it will fit a '4.10 and down'...do they mean in the direction of a 3.54? That's what is in my truck.
2) How would I find out the spline count w/o removing the axle?
3) I have a dana 70. Would I need a case spreader?
4) and one last stupid one...I just want to do the rear and leave the front open. That's doable right?
Thanks for any info.

 

1) Yes
2) Just factory, as you probably run factory drive axles.
3) Yes
4) Absolutely

One small hint.
Keep the shims from each side separate and put them in the same way and order with the new Carrier.
More then often that fits perfectly as the shims are mostly for production tolerance of the axle.

And - Do Not change the gear lash, measure it properly before taking out the old carrier and bring it in to the exact same number. Changing that will give you a howling differential. Even if the number you measure is out of range - keep it.

 

Thanks so much for this reply and added info. I'm still on the fence if I do this myself or hire it out. Gonna use a Yukon LS that my friend has in his Ram and I really like how it handles the snow. Here in the Lake Tahoe area this winter I was really tired of the open diff. Thanks again.

 

I went with an Eaton Trutrac in the rear, I would have gone with an Eaton Trutrac in the front but they don't make one for my year model truck since 2002 - 2002 model year trucks I believe got the odd ball 32 spline axles, so I went with Yukon LS in the front. Very satisfied with both.

 

What year truck is your friend’s? I would rather have had an open rear in my ‘98.5 RWD in snow and ice with the OE limited slip diff. It was worthless in snow and ice. I’ve been told 3rd Gen and newer OE limited slip is different.

 

Not certain of the year. I use to drive a OE LS fuel truck at work with the clutch packs worn out some but still working and it was worthless too.

 

Is it a 2nd Gen Dodge Turbo Diesel?

Mine was in good shape, I’d replaced the clutch plates when I rebuilt the diff. It worked well in gravel and off road situations, but it was terrible on snow and ice.

 

Yes

 

Torque King has a pretty nice little book for not so much money. They have a ton of smalls, their shim kits are really nice.

I'm doing my Dana 44 right now in my '63 Willys.

It's been a project but fun.

The Dana 70 obviously is a lot more HD. But I feel there is alot of cross over for certain items.

If your doing bearings these new style bearing removers are pretty slick. You can find these on Amazon. No need to over spend they sell a where from $105 - $800 and we feel they are all the same, they come with a yellow, black. White clam shell. One hint leave the cups on the bearings and it work to pop off the bearings in seconds with a 1/2 impact.
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This was off Amazon worked well to hold the pinion, torque was a little over 200ft lb for the little 44, so having a decent set up goes a long way.
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Case spreader, this was first time I bought/used one, it's really slick, don't leave it spread longer then needed. (This is just me messing around, my dial indicator is not located in the right spot)
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If doing races deep in the case it's nice to have the right drivers.
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Example of how Torque King packages their kits.
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I was just looking at all those on Amazon trying to justify the cost vs just hiring it out to a shop, esp since I only have this one time I plan on doing this upgrade. The more I look at this the more I think scheduling this at the local gear and driveline shop here in Reno. I'd love to do this myself but I'm 74 now and can't see where I'm gonna do this to another vehicle again.

 

I’ve put carrier bearings in two Dana 70’s, my ‘95 and my 98.5. The ‘95 was open and the ‘98.5 was OE limited slip. Neither required a spreader.

 

Is the 98.5 a Dana 70 or Dana 70u?

 

Personally I should have hired this out.

 

That's probably what I'm going to do but there is positive value in doing a project myself even if the financial part of it doesn't make sense to most people. Plus its another subject I can talk smack with my bro-in-law.

 

70U, as are all 2nd Gen Dodge Dana 70’s. From what I understand, it’s basically a hybrid 70/80.

Properly setting up a Dana is not for the inexperienced. When I say “I” replaced the bearings, I assisted a buddy who knows what he’s doing. It took him several shim settings to get everything right. Also had to modify a set of bearings to a slip fit on the carrier where they could slide easily off and on the carrier.

 

Yeah I just run out of time most of my projects. Had I farmed it out it could be done by now. Definitely was not budget based doing it my way, I think I'm at $1200 with parts and tools. I forget if that includes the locker.

This thing was pretty nasty. I don't have a very good water source and I don't like a lot of harsh chemicals so cleaning it took a while. A shop would put it in a fancy parts washer and be done in a snap. I wound up using a toothbrush for the final steps and some basic scrapers.

I have learned a ton, it's a neat process for sure. When using new bearings the tolerances change and the shim pack do need adjusting on these small ones.

It's 61 years old per the date codes, so it was time.

Much different then your build. Should be much nicer to work on a newer unit.

Went with a Lock Right Locker, kinds plug and play, much different application.

I think my 2nd Gen is a basic Open rear.

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Timd32, your giving me a second thought on doing this myself. I called the local AutoZone and they have loaner case speader and bearing puller so that would save some cash.
I have a parts washer and it definitely helps. My sister doesn't understand why I always save the large cardboard sheets. I must have a stack of 50. Once the weather around here warms up a little more I'll dive into this one. Can't wait. Thanks for the pics.

 

So, you either missed my post or chose not to believe me. All good.

 

Didn't miss or not believe you. I too have a trusted friend that would check my work if I decide to do it myself. Only issue is he's out of state so I'd have to time my project around his availability which isn't a big deal. I appreciate your input.

EDIT: my initial hesitation was the cost of installation tools and since it seems most of the parts stores in the Reno/Sparks area have loaners that concern isn't as overwhelming.

 

I know its a issue of preference, but new bearings require preload, thus the case spreader. I have a set of setup bearings (can be removed easily) i use then press on the permanent ones once I have the final shimming figured out.