Possible Cause of Spider Gear Destruction

[mopar_nocar]

Picked up a 1987 D150. Drove it home and checked the rear axle gear oil level -- could not even touch it. Put a qt in to get it level with the fill hole. Truck would "clang" when put into reverse or from reverse to drive. Then on the way to work, took a left and it acted like it had a spool in the rear end.

Parked it and finally got a chance to pull it down...here are the gears. I fished several pieces out of the housing as well.

What the heck caused this? This is not a hotrod, just a 318/904 2bbl truck with 2.94 gears. Would love to avoid a repeat performance...incidentally, I grabbed a complete axle out an 89 Ramcharger with 3.55s at the JY and the truck is MUCH better for it...going to clean up the original axle and put in 3.90s or 4.10s for the eventual OD trans swap.

sb

 

[67Dart273]

Spiders in many open rear axles are easy to destroy. They are pretty much THE weak link. You get one tire off pavement into a bit of rain, etc, anything to lose traction on one tire, give it some gas and go spinnin up onto dry pavement. And, of course, if the trucks former owner was "still a teenager" or had teen kids................

And of course as a then friend way back in the '70s told me, "It wasn't the time that it broke that broke it...........it was the 10 or 50 times you got on it before, that cracked something or burred something, etc."

 

[mopar_nocar]

Spiders in many open rear axles are easy to destroy. They are pretty much THE weak link. You get one tire off pavement into a bit of rain, etc, anything to lose traction on one tire, give it some gas and go spinnin up onto dry pavement. And, of course, if the trucks former owner was "still a teenager" or had teen kids................

And of course as a then friend way back in the '70s told me, "It wasn't the time that it broke that broke it...........it was the 10 or 50 times you got on it before, that cracked something or burred something, etc."

Touche'

Supposedly this is a 67k actual mileage truck...but who knows? HARD miles maybe?

 

[Trojmn]

8 1/4? or 9 1/4? Whatever you got out of the RC ought to have been a 9 1/4 iirc. We've had probably 20+ 9 1/4 axles in trucks/ramchargers vans, etc over the years... every one clunked going into gear. None ever had an issue either and I was only one of (4) teenagers that abused them often. Seems like bad luck + low oil didnt help any.

 

[Dana67Dart]

My 324,000 mile 7.25 would klunk into reverse and again into drive.

One day I was looking at the brakes and rotated the axle.

Click click click. Not the sound I ever heard before. @jaws suggested I check the fluid level.

Pinky all the way in the hole (keep it clean) came out dry. Put a hose into the hole that curved down, about 3/4 inch on the end.

I put 6 oz short of quart into it. It sounded much better.

Some time later I decided I should see how bad it was so I pulled the pan. The gears looked fine but the spider shaft was sloppy in the dif carrier.

I replaced it with a 8 3/4.

 

[mopar_nocar]

8.25

2WD Ramchargers had the 8.25 for a while...I had an 87 so equipped. If driveshaft length did not come into play a 9.25 would have done me fine. The only 9.25 I had was in an 85 4x4 Ramcharger.

So, what is the best bang for the buck way to strengthen the 8.25 I have sitting in my driveway when I re-gear it...sure grip? Or is there something better out there now?

sb

 

[Dave999]

repetitive shock loading... doesn't have to be a one big burnout thing....
heavy load or a hill, uncapped/ cobbled or ridged road due to heavy truck or bulldozer traffic... constant variation in traction due to wheel hop and shimmy breaks those tiny gears and fatigues the axle shafts.

gears 2.94:1 are hard to turn, tall gears, so slamming a bunch of torque at the rear end every time to get going fully loaded.....not high tailing it outta there, just constantly pushing it.... is gonna involve shock loading. especially if the cone washers were worn giving bigger than normal side gear clearance.

whoever drove it, drove like it was the "company's" truck not their own.... not paying the repair bill, gotta get there in order to get back for my lunch break...etc

this is why they used a modified centre with 4 pinion/spider gears on 2.77:1/360 v8 equipped cars, or at least they did in Australia, a land with a huge amount of uncapped trails and roads, once you get away from the suburbs, you can if you wish, drive for 100s of miles vibrating your teeth loose, fantastic cure for constipation.

sure grip clutch based, or cone diff would work well. the Aussies made do with a 7 3/4 behind a 318/904.. they lasted ok in Utes and vans... 1/2 an inch more gotta be worth something

 

[Demonracer]

A few of the teeth look to have been broken for some time, all of the debris in the housing probably caused the teeth that are shiny to leave the chat.

 

[mopar_nocar]

gears 2.94:1 are hard to turn, tall gears, so slamming a bunch of torque at the rear end every time to get going fully loaded.....not high tailing it outta there, just constantly pushing it.... is gonna involve shock loading. especially if the cone washers were worn giving bigger than normal side gear clearance.

whoever drove it, drove like it was the "company's" truck not their own.... not paying the repair bill, gotta get there in order to get back for my lunch break...etc

This jives with the story I was told about this being a vehicle owned by a school district and used for maintenance crews.

And 30x9.5x15 tires to boot on the 2.94 gear! Original tire size was 205 or 215/75/15 ~ 27" tire. 3 inches makes a big difference.

A few of the teeth look to have been broken for some time, all of the debris in the housing probably caused the teeth that are shiny to leave the chat.

True...wonder if my addition of oil made it worse...meaning the added gear oil provided a medium to get more of the bits suspended or in circulation and hastened the imminent failure. It happened just hours after I topped off the gear oil.

 

[pauly]

I’d be curious on the axle too-8.25 or 9.25. I broke a spider in half in a Dana 44 front axle but guessing the 39.5” Super Swampers helped with that. I did own a 1977 W150 with a factory 440 in it with a D44 front and 8.25 rear. I never had it running but the guts of the 8.25 were totally destroyed.

 

[Bewy]

One wheel burn outs. Loss of traction spins the spider gears at a tremendous rate, causing wear & damage.