A few differential questions

[JakePSD]

I tried searching but couldn't find what I was looking for. My truck has open 3.55 gears. I hate open diffs with a passion and would like to convert it to limited slip.

I have a parts truck that., according to the door sticker, has 3.73 LSD gears. I don't tow much so I'm ok with the higher ratio I currently have for better fuel mileage, and on the rare occasion I do tow something heavy, I do so accordingly. It doesn't have the tow package but I put the bigger on a bigger hitch from one that I'm assuming did.

Can I take the LSD carrier out of the parts truck, bolt my ring gear to it, and put it back together? Would i have to change the pinion gear also? Or would I be better off swapping both front and rear diffs and have the 3.73's?

Are all the front diffs open? Or did they make them in LSD also?

A side question, other than the 3.73 LSD gear and bigger hitch, what difference is there between tow package and non?

 

[IPcamper]

Well, I don't know about just swapping out the internals, but as for the rest...
The front is an open differential and the gear ratio on the front and rear have to be the same.

The tow package for these had the 3.73 ratio gears, the class III/IV hitch, a seven pin trailer connector, a larger transmission cooler, and some had an engine oil cooler.

 

[boominXplorer]

I would swap in the 3.73 axles and be done. These trucks drive better around town with lower gears. You won't notice a difference in highway milage.

 

[JakePSD]

Can the differentials be removed without taking off the wheel knuckles? Will the axle shafts compress that much?

Thinking about it, I might actually get better mileage with my normal driving with the lower gears. My drive to work is about 13 miles with 7 stop signs.

 

[boominXplorer]

Axles of course must at least be removed from the diff housings. All tie rods and upper ball joints must be separated to remove axles.

 

[TechGuru]

I'd convert everything to 3.73, I have a 3.73 and have towed 5000lbs with it and there is no struggle to get going.

I would like a 4.10 someday though, lol.

It takes a lot of knowledge and experience to properly configure the internals of a differential.

I would just swap the whole front and rear diff assemblies with 3.73's and be done with it. Will be much faster than having to rebuild the differential.

 

[Number Twelve]

All tie rods and upper ball joints must be separated to remove axles.

I swapped a rear pumpkin three weeks ago. In the rear, I left the top ball joint connected and got the hub off the half-shaft by removing the bottom bolt and the toe link. Why? Because they are the easier two points to dismantle. In fact, you can take the toe rods loose at the center and that's even easier than trying to break the toe joint at the hub.

Bottom bolt, toe link in the middle, half-shaft comes out.
Repeat for the other side.

 

[JakePSD]

I guess my next step is to make sure the diffs are good, which means driving the parts truck. That'll be scary, considering it sounds like a jack hammer inside the engine block (hence why its a parts truck that I paid $350 for). Oh well, I wanted to drive it anyway to see if the trans was alright. Hopefully a quart of Lucas crap will keep it alive. I'd like to sell it as a rebuildable 4.6L engine, or rebuild it myself.

 

[TechGuru]

I can't tell if you have a 4WD/AWD or not. Just know that if it is YOU MUST replace the front diff with the same ratio at the same time as you replace the rear. If you drive it with different ratios in the front/rear you will destroy the clutch inside the transfer case.

If you wish to test drive with your new rear before doing the front I suppose it would be ok if you removed the front drive shaft but turn 4x4 hi on so the output shaft isn't slipping.

 

[JakePSD]

I have AWD, so having different ratios would kill the viscous unit in short order, which means no removing the front driveshaft either. I plan on test driving them in the truck they are currently in, hopefully the engine holds up long enough to do so.

 

[imp]

Can I take the LSD carrier out of the parts truck, bolt my ring gear to it, and put it back together? Would i have to change the pinion gear also? Or would I be better off swapping both front and rear diffs and have the 3.73's?

Are all the front diffs open? Or did they make them in LSD also?

@JakePSD
Lot of help alrerady, but since I've messed with gears and differentials since around the late 1950s, I'll throw this out: 1. Ring and pinion gearsets are matched pairs. You can't replace one or the other, unless you like playing with LOTS of noise.
2. Whatever ratio you like, everybody is right on: front and rear must be identical, or very close to it.
3. No Fords have been offered to my knowledge, with locking front diffs.
4. You would do best to use the entire donor "pumpkin" containing the LSD you want by bolting it into your truck. If it's any good. And if it's ratio is compatible. If you really want an LSD up front, put in a Torsen worm-gear unit, the only type LSD which provides reasonable safe and useful performance in a front diff. imp

 

[JakePSD]

@JakePSD
Lot of help alrerady, but since I've messed with gears and differentials since around the late 1950s, I'll throw this out: 1. Ring and pinion gearsets are matched pairs. You can't replace one or the other, unless you like playing with LOTS of noise.
2. Whatever ratio you like, everybody is right on: front and rear must be identical, or very close to it.
3. No Fords have been offered to my knowledge, with locking front diffs.
4. You would do best to use the entire donor "pumpkin" containing the LSD you want by bolting it into your truck. If it's any good. And if it's ratio is compatible. If you really want an LSD up front, put in a Torsen worm-gear unit, the only type LSD which provides reasonable safe and useful performance in a front diff. imp

You've been messing with them a while I'd say...

1. I don't want noise. I just got rid of noise by replacing 3 wheel bearings.

2. Definitely, unless I run a VERY staggered tire setup haha.

3. That's dumb.

4. If I swap the rear I'd have to do the front also since I'd be changing from 3.55 to 3.73. That torsen sounds like $$$$.

 

[TechGuru]

I personally would rather put a electronic or air locker in the front rather than a LSD in the front.

 

[JakePSD]

I personally would rather put a electronic or air locker in the front rather than a LSD in the front.

I'll be leaving it open. Its not an off road rig. This is more or less just my winter/snow vehicle. I wanna keep costs down. I'm already deep enough in this thing as it is. Replacement engine, rebuilt trans, 3 new wheel bearings, ball joints, tie rods, struts, the list goes on.

 

[boominXplorer]

I personally would rather put a electronic or air locker in the front rather than a LSD in the front.

I love my front Torson. I have put 20k miles on it and the only time I know it's there is when I really need it. I have a grizzly locker in the rear also and it's way more of a nusence. Since all the traction adders it doesn't get driven in snow unless I'm playing around. It likes to slide straight when turning unless under throttle. Also usually the only time I get stuck off road I get high centered on something because of my long wheel base (Ranger is a foot longer than an explorer). If I got weight on a tire usually I can get out.

Thread off course done

 

[JakePSD]

I love my front Torson. I have put 20k miles on it and the only time I know it's there is when I really need it. I have a grizzly locker in the rear also and it's way more of a nusence. Since all the traction adders it doesn't get driven in snow unless I'm playing around. It likes to slide straight when turning unless under throttle. Also usually the only time I get stuck off road I get high centered on something because of my long wheel base (Ranger is a foot longer than an explorer). If I got weight on a tire usually I can get out.

Thread off course done

What did that cost you?

 

[CDW6212R]

The front Torsen is still available given their rare manufacturing runs, for about $520 shipped. I bought two recently for my two main SUV's.

The rear diff's run in the $350+ range depending on which brand etc, there are lots of 8.8 choices. The Eaton 8.8 a lot of people like is under $400, and Eaton has a $50 rebate until the 31st. I'm aiming at their True Trac which is about $100 more, and it's like the Torsen, being a clutch-less gear only diff.

Installation is the hard part, finding a competent shop and priced fairly.

 

[boominXplorer]

^ prices are above for parts. My 8.8 grizzly was just under $700. I install my own diff parts but most shops will do a rebuild on an axle for $4-500 labor if the axle is out of the truck.

 

[imp]

The front Torsen is still available given their rare manufacturing runs, for about $520 shipped. I bought two recently for my two main SUV's.

The rear diff's run in the $350+ range depending on which brand etc, there are lots of 8.8 choices. The Eaton 8.8 a lot of people like is under $400, and Eaton has a $50 rebate until the 31st. I'm aiming at their True Trac which is about $100 more, and it's like the Torsen, being a clutch-less gear only diff.

Installation is the hard part, finding a competent shop and priced fairly.

@CDW6212R
You say Eaton offers a True Trac? True Trac was one of the original names for the first Torsen, the name has been bought and used by several different companies over the years, including Detroit Gear, which made the original Detroit Locker, I believe.
imp

 

[CDW6212R]

@CDW6212R
You say Eaton offers a True Trac? True Trac was one of the original names for the first Torsen, the name has been bought and used by several different companies over the years, including Detroit Gear, which made the original Detroit Locker, I believe.
imp

The True Trac is listed as being an Eaton Detroit Truetrac, so it looks like Eaton and Detroit have merged in some way. Here's the Summit link to the 8.8 unit I'm planning for;
https://www.summitracing.com/parts/dtl-913a561