Time to mildly overhaul the rearend...

[marquis_82_withneons]

here we go, time to dabble in unknown territory for me. So boys, the base to start with is my 82 Merc with 3.08 open diff. 100% stock, and to my knowledge, untouched from factory. if that is the case then i wont have to deal with someone elses handiwork, however it also means i have 175k of wear to deal with. i have wayyyyyy to many variables floating in my head to sort this for a first timer, so ima do my best to lay out what i assume/think is gonna go down and what im prepared to do in the process. i have access to parts and tools and can do work myself. so most of the project will be second hand stuff. theres going to be a few alterations in the mix so please chime in for tips and tricks. so here we go..

1. i plan to keep the axle in the car for the time being. (lack of space at home)
2. this will be a 5 spd car, i know a different driveshaft is needed. will this affect the pinion flange? ive read that it will.
3. assuming the axles are original, if they are scored badly, i will locate replacements but aiming to keep ones i have.
4. i have a used 28 spline trac-loc from ranger/explorer/whatever to go in. purchased on ebay (planning on thorough inspection and new clutches)
5. 3.73 gears are the plan at the moment, still trying to locate. tips on finding good used ones? sharp gears mean they are heavily worn, correct?
6. are all spider gears in trac-locs the same? providing it is a 28 spline unit.
7. axle bearings and seals, no brainer. tips on removal would be helpful though.
8. disc brake swap is very tempting but i dont think im finacially prepared for the little things that add up fast. so for now im gonna put that off the table.

im just trying to plan out an order of operation so to speak. ive searched and found plenty of info in regards to most of my issues independently, but not as a whole and i want to ensure i have the correct info before i disassemble my backup car. im probably over-complicating things but thanks for the help... i know i missed crucial info there somewhere, lol

[jaywish]

If you are changing the gears you will need pinion bearings as well. Buy a complete overhaul kit with all bearings, races, seals and crush collar. I have used FRP a couple of times with no complaints. Others may suggest other kits. Ford sources the parts from typical manufacturers.
I would expect the axles to be worn at this mileage but you never know.
Can the car be laid-up for a while while you do this project?

You have the dial gauge and magnetic mount? Do you have access to a press and appropriate spliter tool? Inch lb. and Foot lb. torque wrenches?

Some folks don't measure anything and they have good results but with a new carrier and gears you may have a shim issue. Probably not but you may.

Swapping gears and carrier is pretty much a complete overhaul. You are not going to use the old bearings and such.

[marquis_82_withneons]

im essentially doing a junkyard rebuild. im going off of what i have to work with. i cant afford to buy new on most of this car. so as things have worn over time instead of replacing the junk with other junk from the yard. ive slowly replaced it with better junk. so out with the old clunky, open, highway, gearset. and in with an explorer trac-lok sporting mustang gears.

i do have access to all the tools needed. thats why im gonna try it myself. that and i cant stand to pay someone else to do a job that isnt to my own standards. so as long as i find some reasonable quality used parts, when they get installed itll basically be a junkyard upgrade.

[gadget73]

You have to replace the crush collar when taking this apart, and you will need the bearing to match the race. You really don't want to bother driving the race out, so get a new bearing. Replace the pinon seal while you're at it. Replace the axle bearings and seals too.

Not to be a dick, but if you can't afford the bearings and seals to do this right don't touch it.

[mitymerc]

Probably want to replace the Tracloc clutches as well.

[jaywish]

Sets like these.
https://performanceparts.ford.com/part/M-4210-C3

https://performanceparts.ford.com/part/M-4700-B

[Brown_Muscle]

I'm uncertain of what vehicles came with 3.73 8.8's, I imagine trucks. 3.55's are more common. To drive out the axle bearings I bought a 6' pipe and was able to hammer them out from the other side once everything else was removed. You can get a bearing puller/slide hammer too, but a pipe is cheap and it works. The pinion bearing has to be pressed off and on, if you have a press perfect, if not a friendly shop might do it for minimal cost, or free, it only takes a few minutes.

If you find used gears you should be able to feel if they are worn, you'll see where the teeth engage, however there shouldn't be any wear in these areas, you can feel them with your hand. Ideally to avoid noise you want the wear pattern to be precisely where it was in the previous differential

Also if you use rockauto you can probably piece together a kit for cheaper than ford racing, I recommend Timken bearings, and national seals. That's what ford used from the factory, I haven't had any problems with mine

[jaywish]

You know I really like the pipe idea.

[Brown_Muscle]

I can't take credit, someone else on this site recommended it to me years ago, although I cant remember who.

[gadget73]

Dereck actually posted a tech article on 8.8 axle bearing replacement using a pipe. It does work, just have to be careful and have a space basically 3 cars wide to make use of it.

Old bearing races make a good install tool too, just need to grind them down a bit so they don't actually press in anymore.

[marquis_82_withneons]

update on the subject.. trak lok showed up, needs a rebuild as expected, but ive shifted from overhauling my current axle, to removing it and swapping a 95-97 rear. i want the wider width and disk. been eyeballing that swap for a number of years, figure now is the time. so i will be doing all the above mentioned work on the donor axle and not my current one. if i get lucky and find a rear with 3.55 already in it, then i might roll with it.. eh, we shall see.

love the pipe idea.... thats definitely happening.

[mitymerc]

Much better plan IMHO.
I did the same when the main cap broke in the 91. Unfortunately, I ran out of time to mod the parking brakes & stuck the drums back on.

[sxcpotatoes]

update on the subject.. trak lok showed up, needs a rebuild as expected, but ive shifted from overhauling my current axle, to removing it and swapping a 95-97 rear. i want the wider width and disk. been eyeballing that swap for a number of years, figure now is the time. so i will be doing all the above mentioned work on the donor axle and not my current one. if i get lucky and find a rear with 3.55 already in it, then i might roll with it.. eh, we shall see.

love the pipe idea.... thats definitely happening.

I've got a '97 GM rear with discs under my '82 Mark VI Tudor. I had the transmission shop just slap it under there. I have a rear PI swaybar I need to find someone semi-local to powder coat it before I put it on.

[P72Ford]

Explorer 8.8s can be found with 3.73s, and 4.10s (I think only V6 trucks). Do your research on axle codes (and verify as well), and you should be able to find them. The carriers are 31 spline though (I believe all of them), so the carrier itself is of no value unless you are going to 31 spline axles. Also, remember that used gears have developed a set, and you may run into noise if you don't have the mesh pattern like it was from the factory. The nice thing is that factory gears are good (arguably better than some aftermarket stuff), and if they're used they are "broken in". I would like to look at them in person before buying, but thats just me.

I would recommend 3.73s or 4.10s if you are looking for a fun car, and fuel mileage isn't a deal breaker. If you plan to do a lot of highway driving, or don't want to give up as much fuel economy, the 3.55s are really a nice compromise. My mustang (302/ T5/ 8.8) has 4.10s, and sometimes I wish it was a 3.55 car for better highway manners.

In my opinion, if you are doing this on the cheap, you need to rebuild the differential. Putting in a spent unit, or rebuilding it with junkyard parts is a waste of time. Need to rebuild that; in order to go in and do it after the fact is nearly twice the work.

The axles have to be good. I do not endorse repair bearings, as I have never actually seen them last. All the seals need to be new. All the bearings should be new, or at the very least have matched races. Up to a while ago, (and hopefully still), Rock Auto had a overhaul kit with Timken bearings for like $80. This is a no brainer to me. Reliability is key to me, and a rearend job isn't necessarily a beginner's job, so I would save my money and do it once.

You need a dial indicator with a magnetic base (old timers will call this a "last word"). Gear paint (which comes with the install kits), is, in my opinion, more important than backlash. Make sure the contact pattern is good on the drive and coast side.

Ideally you want the use of a press. I like to grind out the inside of my old pinion bearing so it slides onto the pinion, and you can remove it and change shims under it without the hassle of a press. Then press your new bearing on when you have pinion depth correctly identified. Yes, its a different bearing, and there will be manufacturing variance. However, it is on the order of 4-5 decimal places, and not the 3 you are concerned with for this job. Its negligible.

Look into a crush sleeve eliminator; I have used them with excellent results, and would not go back to a crush sleeve (unless its strictly a rebuild with no gear change).

[gadget73]

Last Word is a specific Starrett indicator. Its not a particularly amazing one either. They're prone to sticking. The advantage they have over many others is size, they're pretty damn small compared to many other designs. If you're doing it with a mag base, get a good one. Weak ones fall off and the indicators get smashed.