2nd Gen Non-Engine/Transmission Homegrown Spool...

[jpickens]

When u can't take the slippy limited-slip anymore... take 5 and spool it up!



http://www.ezpickens.com/josh/bigbrowntruck/20041114dieseld80locker/



Okay before everyone flames me for just throwing this together one night...

A) if/when it should break, an open carrier and locker are being installed.

B) it's got almost 15k of 'hard' use and fairly heavy towing (20k+gcw) on it and no signs of giving up the ghost! (I drive 40+ miles round trip to work everyday to boot etc. )



Nothing like 4th. gear drifting on dry pavement! Oo.

I hope someone out there can smile and imagine the fun I've been having...

hahaha



Josh

 

[jpickens]

Managing tire skipping... ?

Well it skips/skids/scrubs right along anytime your not going in a straight line.

BUT if your going say over 10-15mph you never notice it.

Going under that speed especially making tighter turns in parking lots or around corners it's completely obvious. The more weight your hauling the more 'violent' the skid/scrub/spin (whatever one wants to call it). This is due to the fact that the axles get 'loaded/twisted' up more (kinda like a torsion bar) before the tire breaks loose and equalizes with the other side. The newer your tire is, i. e. the more tread depth you have the less noticeable... I'm assuming since the tread itself flexes a bit softening the scrub. BUT tires don't last long scrubbing all the time. When I put the spool in it quickly did away with the 295 bfgs i was running in a few thousand miles. They already had 25k on them though.

Then I threw on a new set of pro comp 315 ATs and with my best guess I would say it cut their life by almost 30% having the spool. Instead of getting about 30-32k out of a set of tires (which is typical for me - and I run them well into the wear bars), I'll probably only get 23-24k max.

I could live without the scrub for sure... but I guess the fun/traction/go in 2wd where I used to run 4wd/cheap-quick & did it myself aspects of it out weigh what most would consider very annoying.



I often wonder what would break first...

weld/spool itself

ring/pinion

or axle



I'd have to guess that one of the axles would go first. I know they are HD (1. 5" 37 spline i believe) but if you could witness how much they act as torsion bars when your loaded heavy and turning rather tight on dry asphalt/concrete you'd wonder how they lasted this long.

They bind up and then snap/scrub one of the tires while turning, almost always the inside, allowing it to equalize with the distance the outside tire has traveled.

I. e. it spins vs. drags the tire that's catching-up/scrubbing therefore making it easier to break them both loose with application of a little throttle in a turn.

I don't guess any easier than a completely open diff though. But it's no fun just spinning one wheel. :-laf



I'll try and take a vid of it turning tight in a parking lot so you can see for yourself... little movie is worth more than I could ever explain here.



Josh

 

[Fishin Guide]

You could break any of the components listed, with the axle getting the brunt of your mod.



Also, don't forget about the bearings and the housing itself. I have seen spools cause enough side force to shear and axle at the carrier, wasting the carrier, axle, bearings and the housing itself. Sometimes there is so much enerrgy in the housing, it can become "irregular shaped" resulting in turning it into trash. Also, the bearing bosses can become wasted. Sometimes they can be remachined, sometimes you need a new housing.



Just for the additional cost of tires, you could pay for a quality rear differential in short order, not to mention the other parts in the puzzle.



I would never recommend a spool on the street. I know some people run them seemingly without issue, but most guys don't know where to look in the housing for signs of fatigue.



A simple thing you can do to help track wear on the axles is pull them out, paint a straight line down one side from end to end. I like to use about a 1/2" white line. Pull those axles after a few months and you will see if they have any twist.



This is an old drag racing trick, but under the right conditions, you will see it on heavy truck axles as well. Problem is, they usally brek/ shear before you get much twist due to the diameter/ density of the metals.



Dave

 

[pwerwagn]

I have welded diffs in my 74 power wagon, and in the rear of the bronco. It isnt to bad, but I wouldnt do it on my cummins!!!!

I used to tow pretty heavy with the 74, and I broke a few 14-bolt gm axle shafts that way.

I agree with fishing guide. most people dont know where to look for signs of stress in the housing. heck, most people dont even know how to set back lash, let alone set up a ring and pinion.

Personally, ill take my one legger and tires that last over this mod. but thats just MHO.

Oh yeah, also you can re-stack the clutch pack in the lsd and get a TAD that works quite a bit better than stock.

--Jeff

 

[jpickens]

Good Feedback! Most of those thoughts have went through my mind... I guess I am willing to live with the possible negative outcome.

I will pull the axles and paint the line though. I like the idea of being able to monitor the situation with some frequency of feedback. I have performed similar mods (not the "running a 7018 in the spider gear trick") mostly on lighter duty gm axles with great success. The axles/axle yokes/ or steering u-joints are what always failed.



I agree with both of the posts above... most people don't know how to maintenance/repair differentials properly. It's not rocket science but I'm not a materials engineer either.



"Oh yeah, also you can re-stack the clutch pack in the lsd and get a TAD that works quite a bit better than stock. "

Agree 100% - it did help a bit back 30-40k ago when I realigned them for maximum friction but that eventually 'loosened' back up upon wear as expected.

I just figured I'd try this since I would have to obtain an open carrier center section to run a real locker anywho... believe me, once those parts are in hand the spool is out. It'll be interesting to see if I get them (open carrier/locker) gathered up before something gives. haha



This definitely isn't a mod for 99% of the owners out there... but for that 1% that are willing or in need (pulling trucks etc. ) it seems to work ok since a widely available/commercial (not one off'd in someones machine shop) spool for a D80 has yet to surface to my knowledge.



On another note... along the same lines as a major failure that would result in extensive machine work or complete replacement of the D80 axle itself... Your transfer case and transmission are not exempt from seeing some of the abuse being spooled transmits up through your drive line.



Josh

 

[Fishin Guide]

And just one more note, and this is the kicker, you may never have a problem.



So, even with all the negatives, sometimes some parts do survive. I can't explain why, but that's just the way it goes.



You are a smarter fellow for talking the good and bad information with a grain of salt and digesting it fully. Besides, it really is your truck and as long as it makes you happy, that's all that matters.



I agree about the full time racer, sled puller rig that is a purpose built machine. Alot of these use special trussed axle configurations. And, well, racing and or sled pulling does break parts. It's expected on the track. I would just hate to see your daily driver leave you stranded. I get enough of that with bad lift pumps. :-laf



I just want to be of as much help as the folks on here have been to me!



Dave

 

[MDW]

I like a guy who is willing to put forth the effort to mod his stuff and accept the consequences.

Would be funny to see the look on the faces of the service guys when they took that apart for warranty :-laf

 

[jpickens]

One more thing to note for the welders/fabricators out there... (of which I am truly a novice even though this was a quick/dirty job for testing purposes - not my best work by any means etc. ) Welding the steel spool plates to the cast carrier housing is tricky. I should have taken the time to preheat the housing before welding and apply post heat control so it cools slowly to attempt to alleviate cracking. None of the pictures actually show the plates fully welded into the housing all around their perimeter. I did that after a hairline crack formed in one of the stitch welds as it cooled. Of course I'm sure some fancy alloy mig wire specifically for this type of welding might be available similar to using high nickel content rods when doing this with a stick welder etc.

If I had a machine shop set up I would have made the plates about 1" thick with the 4 prongs and the perimeters of the plates having such tight tolerances they would be a virtual press in fit to the carrier housing. Then machined splines on the inside hole that the side gear would have slipped down into much like it slips into all the friction discs and 'clutch' plates of the original limited slip setup.

Then you could have reproduced them (2 plates to a kit) and anyone wanting to do this mod easily, could. AND - it would be (in my mind without any more thought into it) sorta reversible.



Josh