Technical Severe rear end hop

I broke the G80 (GM Posi-like center) in an OT truck. A chunk of the busted guts stuck between the clutches and locked a rear tire. If you don't see any busted or odd-looking suspension, pull the center section. Even if it isn't catastrophic, fluid color and smell can tell you a great deal. Be sure to use a Posi Additive upon refill. I have had the best luck with the Motorcraft stuff from the Ford Dealership.

 

many times wheel hop is caused by the nut that connects the steering wheel to the gas pedal.

 

Yep most problems we have are associated with the loose nut behind the steering wheel, at least for me.
Dan

 

I'm thinking the same thing as i was just cruising down the road and not doing anything crazy.I took it out for a 35 mile drive this evening and it's all smooth and normal.The car drives and rides great as always.

I hear ya...I'm 64 and still flying aerobatic biplanes,riding sport bikes and driving badass hotrods ..ya gotsta spend your money on something...quoting the lyrics in a soundgarden song...nothing seems to kill me no matter how hard i try...just an old guy having fun and not hurting anybody.

 

If you haven’t found anything external as stated above,if it was mine I would pull the third member and check everything in the differential. If you don’t find anything -great- but if you do you’ll save yourself a mess later. A locked up rear end at high speed is no fun I know from first hand experience. Nine inch rear ends suck from an inspection point of view since you have to pull the third member however a couple hours of work is worth piece of mind in my book YMMV
Dan

 

Yep that's what i plan on doing ...Thanks

 

In the world of computer tech support it's referred to as PEBKAC, which means:

Problem exists between keyboard and chair.

 

I learned the lesson about the curves and rough roads first.
Broken parts was just part of the game, I had a whole stall of the garage full of broken parts as trophies! I was really good at it! The lesson of the cost of the broken parts took a bit longer to understand. I was a bit of a slow learner.

 

Get a stethoscope, put the rear end up on jack stands, throw it in neutral and get somebody to turn a rear tire, one side at a time and listen for crunchy noises from the pumpkin and from the housing side. Everything in a 9" is large enough that if something breaks, you'll hear it.
Don't waste your time and energy pulling the third member until you've done this and checked the fluid for garbage.
Just my $0.10

 

Don’t you have to pull the 3rd member at least partially out to drain fluid?
Dan

 

Not if you have a pump - Mityvac with vacu-tainer or one of the $80-144 hand-pump or pneumatic units from Harbor Freight

 

Will it suck up metal debris? I like the stethoscope idea!
Dan

 

Do what your DR would do if you complained about rear end issues, stick an inspection scope in there and have a look see (sound of rubber glove snapping).

 

This what I love about the HAMB, you all might not be right but you all have some wisdom and good ideas
Dan

 

Building my 9" for my 31' the first thing I did is weld a bung into the bottom so I could drain the fluid with no fancy gadgets or major work involved. Welded a ring around the plug onto the housing to protect the plug should I hit something and for using a jack under the diff.

....

 

You can pull the pinion and housing by pulling 5 bolts. You can inspect the ring and pinion then. You can also check the housing bottom for debris.
If the trans locks up it will give the same results.
If the rear end is OK, I would pull the trans side cover.
It might also be a linkage problem.

 

I’m going with the tight rear brake shoe as suggested a while back. Either just slightly too tight or has grease or something foreign on it. Off-topic 2010 through 2012 I think F150s, the rear parking brake shoes hang up and do exactly what you’re talking about.

 

Well nobody suggested it so here goes. Pop quiz, where is the rear axle when you're in high gear or O/D?
A) same as the relaxed/stationary position
B) rotated slightly down
C) somewhere between "launch position" (pinion raised) and relaxed/stationary
D) maxed up like from a dead dig.

If you picked C you're about right. All the drive parts are in full load in high gear, more so in OD, but the suspension is partially loaded. If you think I'm full of shit that's fine, but then ask why these cars feel like they settled a little when you let off the long pedal. That's the suspension relaxing. In order to check broken parts you need to get a jack under the nose of the pinion/case and put a little pressure on it. Now see if a weld bung, rod end, frame or axle mount, shock eye are still right where they belong. Many a car ends up "...and I got under there and it was all tight..." only to finally break catastrophically. For the few minutes it would take to simulate the load its worth it. I'm not tryna be the profit of doom here. I just have a habit of the simple shit 1st. Good luck, hope it was just an anomaly, but load it a little. You'll preserve your SPG (smiles per gallon) knowing that was checked.

 

I put the drain plug in the middle of the housing, although I used a flush Allen hex plug I did put a ring around it about 1" high to locate the floor jack.

 

My older brother in all his wisdom [I thought so] never used the parking brake, always left it in gear. The cable would rust up and the proper deviation in the round would stretch/bend the cable and give that side brake a good what for; if not locking it up. Also not using the parking brake meant the car occasionally found its way across the street!

 

Oh yeah...caught a 4X4 with my pickup on the 5 at about 75, moved me over about a half lane.