'pants

So a few weeks back, I ran over a black trash bag, and it wrapped around my driveshaft. I mistook the flapping for it just having hung on some random non-spinning snag point under the truck, and couldn't easily pull over right away, so hoped it would just re-gift itself to some other lucky person. It finally detached a mile or so later, to blissful relative silence.
When, 10 or 15 minutes later, I backed up my steep-*** dirt-and-rock driveway (4WD mandatory), parked, and walked around the back of the truck, the unmistakable aroma of cooked gear-oil wafted into my nose. Eff me.
It's a dump-bed conversion, so I could see quickly that there were shreds of oily black plastic decorating everything under the bed that could possibly hold a piece of plastic. The undercarriage had been basted with gear-oil during that session, too.
Yeah, so...the GD bag had apparently worked its way back on the spinning driveshaft, and wormed into the pinion seal, where it jammed as much Contractor Strength plastic into the seal as possible before departing, ripping the crap out of the seal in the process.

Two weeks later, back from our initial move to the other island, I found that not a single shop in town was willing to work on it: it's 20+ years old so the manager won't do it, we're too busy, our mechanics don't work ON DIESELS (yeah...) So I had to suck it up and DIM.

That 1-7/8" socket I ordered, carefully avoiding the pitfall of having to grind it down to make it fit - the one that came in just in time today? Yeah, Amazon had the wrong OD stated in the product data. Two+ hours of grinding it took to remove 0.2" of radius to get it below 2.5" overall, doing this with a cobbled-up Fred Flintstone lathe (and three+ 4.5" grinder discs). Surprisingly, though, once I got the socket to fit, the nut whipped right off with gentle coaxing from a massive 3/4-drive air impact.

*This* was the easy part.

I never expected that getting the pinion yoke to come off the splines would be ANYTHING so hard as it has been. I've got a huge puller on it (two jaws, about 20" long, with a 1" threaded shaft) but the shaft wasn't quite long enough so I had to extend it, using a ghetto combo of a deep socket wrapped with enough masking tape to be held centered by the original pinion nut. Now, recall I mentioned something about "dirt and gravel?" No lift. We're talking cardboard for comfort. The puller is so heavy and awkward that I had to use a ratchet-strap to suspend it at about the right height - actually worked pretty well. And I can drive it with my electric impact (probably not great for the threads, but I like the impact's hammering action to... maybe... help break it loose?)

Sucker popped off on me, twice, luckily restrained from facial-whacking by the ratchet-strap. I've heated the yoke (propane's all I've got) to the point where the oil-fire that was sputtering to life seemed like it might get me out of the whole problem right there. I've beaten on the back of the U-joint ears to the point where I'm afraid I might warp them. I've used a pipe as a drift to do the same, all while having something like 150 ft-lbs of torque on the puller, and there's been not the SLIGHTEST movement of the damned thing.

I'm actually having to rent a car to get to and from work, since this happened right after we shipped our daily-driver to another island where we're moving, so this is more than a little aggravating.

At what point do I get on the yoke with a plasma-cutter or wafer disc, attempting to split it off the splines?

I don't have any great smoke-and-mirrors penetrant, just numb-nuts WD40, but I went to town with that, to no avail.

Any ideas?

Dave

u2slow

Have you tried to drive the pinion out with an air-impact hammer or sledgehammer blows? (carrier removed of course).

There's a lot of big parts there to soak up heat. Speed of heat matters too because you want the yoke to heat faster than the pinion. Try mapp gas (yellow bottle) and if that's not enough, you need acetylene.

'pants

I hear you. MAPP doesn't really exist anymore but you reminded me I did buy a bottle of whatever the replacement gas is (also yellow) for some project I set aside, and could try that. I did hammer on it, but fearful I might warp the semicircular retainers for the U-joint bearing cups, which couldn't be a good thing.
Closest thing I have to what I'd really like to try (a demolition-use chipping hammer) is a muffler gun. The blows from it are loud as hell, of course, but I generally find it's all sound and fury, and in the end, signifies that a cutting-torch is imminent. Still, it's worth a try.

A recurring interruption to my dreams last night was some means of rigging up a chain-on carrier for a porta-power cylinder - eg looping it around the yoke to provide a perch for the hydraulic cylinder, which would bear on the threaded shaft with the nut threaded on loosely to protect the threads. I think that's going to be my first effort today, since it seems most likely to succeed with the least potential for ruining the yoke. It's SO satisfying when a stubborn assembly like this gives it up with a mere press of a foot-pedal (air over hydraulic pump).

But it's been raining all night, so the comfort-level of this effort has gone even further down the crapper...not my favorite Sunday activity.

texasprd

WD40 was never intended as a penetrant so you might try something more dedicated. CRC makes one called Freeze Off that's supposed to somehow chill the surfaces and make openings for it to get into. I've used it with heat but can't point to how successful it is - I just know I got the target off in the end. I've heard a 50/50 mix of acetone and ATF is an outstanding penetrant, but never tried it.

Good luck!

'pants

Thought I'd close this out in case anyone stumbles through with similar problems:
What worked for me was keeping (rather huge) tension on the big puller, while alternating 180 degrees with a muffler-gun fitted with a very well-blunted old chisel bit. It STILL took a while to get it to release.

On the way out, I found the 'polished' yoke-to-seal mating surface had a dark groove in it (where I suppose 130K miles shows up as the collective abrasion by a billion particles of road-grit being held against that surface by the old seal), but had nothing left in me to do anything about that, so that's how it went back together. And I'm happy to report that it doesn't leak.

I'd looked all over to determine for sure the gear-oil volume I'd need for this Dana 80. Turned out I might as well have guessed. A bought a gallon plus a quart after settling on the wrong info that it'd be 1.1 gal...now with yet another quart...and it's still not back up to the filler hole. My only guess as to "why" on that, is that I wiped out the bottom of the diff case to completely remove the old gungey sedimentary layers, and maybe it's assume that no one will do that. Also possible that a lot is normally retained within the case, even if you're working on a normal level surface, but I was on a mission to clean the damned thing out and really could only estimate how much would drain if it had been level.

May you never need to go through this.

SIXSLUG

Great adventure..."get a diesel" they said...."you're gonna LOVE it" they said...

I can't remember what mine took on the drain and refill but I don't think it was a gallon....I can look it up tonight.

You should write for some show or ?

Kurt

'pants

Thanks, Kurt. I never had the ***** to actually "write" as a vocation, but I do enjoy the process, even more than I do, say, the cobbling together of random offcuts, grinders and cordless drills to grind down oversized 1-7/8" sockets. (Amazon did get an earful from me about that, and I'm pretty sure they will quake in their boots next time my number comes up on their 'incoming calls' screen.)

I'm about to post elsewhere with my all-new Adventures with Algae. You won't want to miss it.

SIXSLUG

Caught the algae adventure, good write up!

I was mistaken on my dif volume, apparently I install 4.8 qts of 75/90 in my Dana 80, this brings it just a bit below the fill plug on level ground.....

Kurt

'pants

I need to import some level ground...very little where I live. I was peering into the filler-hole, as it swallowed the sixth quart, though, and my eyeball-compensator for level was telling me that it STILL was going to be short, even if I had been on that mythical level ground. Prolly somehow coming out into the fuel tank...