Technical Severe rear end hop

Hello...I have a 32 3 window coupe with a 383 stroker and a tremec tko 500 with a ford 9" trac loc rearend with 22,000 miles on it. Yesterday while driving on a rural hwy doing about 65mph i had severe and violent rearend hop that only lasted about a second but bad enough to get the car almost sideways and when i corrected for it it went a little sideways in the opposite before settling down to normal and the rest of the 12 mile ride to home was normal and uneventful.Lucky there was no oncoming traffic when it happened or it could have been a disaster.The rearend has always been smooth and quiet when going around turns but it seems to me that maybe the clutches locked up for some reason.Any thoughts would be appreciated as i don't need this happening again.I do have a lot of launches and burnouts on the drivetrain but it's been bulletproof so far.

Thanks

 

I think you should get under it and find out what part of the suspension is broken.

 

Crawl under it and see if you see anything mechanically broken .

Drain the diff fluid see if you see metal or clutch material .
Burnouts and launches only last so far before bulletproof becomes bullet riddled.

 

We need to know what rear axle and suspension you have.

photos would also be great.

could be as easy as a tire with a broken belt in it, could be a broken leaf spring. Shit you may have not seen a hole in the road and hit only that tire. I know I’ve had the same results before

edit: it’s always been smooth and quite. Has it returned to that now?

 

I would not hazard a guess what is wrong. After that serious failure that didn't cause more damage, I'd get the car up in the air and perform a front to rear inspection of everything!
You've had 22k of trouble free driving and fun. It now has warned you that 20k is the maximum interval to check things fully. Do not find one thing, fix it and get back on the road. Look it over fully.

 

As others said, you didn't say what the rear suspension is.

Tim is right, it could be anything from a broken bracket, a worn out bushing or broken or loose bolt, separated tire, etc.

My wife came home one day complaining that her car was driving funny and the tires were really loud. There was a badly separated tire.

The car has warned you that something isn't right. It could be the diff, sure. I wouldn't drive it without thoroughly checking out the whole car as others have said.

 

I agree with getting under it and looking things over, spin the wheels while up in the air see if it shows anything, look at your shocks and mounts, check your brakes too.

 

Like mention above
From Checking out transmission to rear suspension and
rear differential,& bearings

 

Thanks for the reply's....Its a ford 9" with the 31 spline axles and a heavy duty triangulated 4 bar set up with qa1 coil overs with the Heidt's superide IFS up front ...i should have mentioned that i did get under the car and everything looks solid...i took my OT truck down the road looking for a big hole i might have missed and didn't see anything thing...Like i said in the first post the ride home about 12 miles after that happened was totally normal.
I think i'll change out the clutch pack and put in some fresh gear oil and a bottle of friction modifier just to be on the safe side.Once again thanks for the reply's.

 

Huh?

 

here's some thing to read..... tires do whats called tire walk...usually happen more on new tires and tires with low air pressure... next going down the road, one tire starts to follow a groove in the road while the other tries to stay on the track following the rim... the side wall push goes only so far before it tries to break the traction to the road...as it rebounds back it causes whats called tire shake... I drove front engone dragster and when it happens it''ll shake your eye balls loose... both tires are trying to grip, but in slightly different directions

 

I'd still be going over the suspension first before tearing into the rearend. Sometimes we get it into our heads that it can only be this and forget to check and eliminate everything else first.

Checking should include making sure that the rear tires are still balanced. I've seen sudden vibrations caused by lost weights especially at certain speeds.

 

I've had that happen in the 77 F250 I drive on a road in this area. Lots of heavy truck traffic on that road and heavy farm equipment and if you aren't paying attention in a couple of spots it can get a bit hairy I don't know if this truck has a limited slip or locker or not.

 

If you were going straight when this occurred the clutches have nothing to do with it. There may have been something in the differential that caused momentary lockup though, and that's serious. Hopefully you'll find evidence.

 

I agree with this if something (broken gear piece etc.) goes through ring and pinion it might lock up momentarily before spitting out. My two cents
Dan

 

Fully agree, it is NOT the clutches in the Trac-Loc......they either hold both axles to spin both or they release when cornering....they cannot lock the center section up.
When they go bad, all they do is slip.

 

Clutches in the rear end DO NOT cause wheel hop at 65 mph.

 

Exactly.

 

Nothing to add, but @acroguy tge rear suspension will get a pass on the HAMB, but edit out/delete the front.

 

Exactly what I was thinking. I’ve had a couple ring gear teeth break off and the rear end sounded normal. Only clue is when they broke and temporary locked up the rear end. You’d be crazy not to check into it.

 

Okay will do thanks

 

Possibly a loose brake shoe floating around and getting caught up...?
Had that happen once, only the shoe didn't let go...because the axle had slid out! Car went sideways down the freeway, in heavy traffic and didn't hit anything. Sounded like a bomb went off and the car was instantly out of control. Got lucky on that one.

 

Im thinking to like other mentioned
Some thing went threw pinion and ring gear, that was my main thought ,
But I mention the other things previously
Transmission
Suspension , bearing,
Deferential.
What type transmission you using , just curious?
Aweek ago I took my car out for a ride & testing , on way home I did 1 last hard pull , (100 in 1/8) , I was close to my shop , Less then 1/2 mile away ,after pull driving 40 ish to shop,, afew days later went out to testing again , @ 45 mph a hell of noise , thought I broke another transmission, Thinking the worse put it on the lift & seen that Bindex gear on the starter was up against the flex plate , So I took Tilton
apart & found Bendex
Spring was all twisted up, found a spring from brake stake pin , & fixed

 

Had an O/T euro car years ago do something similar , every now and then you would get a violent shudder and noise from the rear end like the brakes where locking up or something on the wheel binding .

could not find anything wrong , eventually became a loud bang on the hwy with all sorts of bad vibrations and not so safe things going on.

Ended up finding out it was in the diff , pulled the diff apart and one of the pins holding the spiders in place walked out and was hitting the diff housing intermittently, lucky it didn’t lock the diff solid going down the hwy .

 

After a lot of racing, dad's station wagon with a heavy duty built 12 bolt will jump around corners bad. It takes a couple hard right and left turns to free up the clutches and get oil back into them. Once a couple turns are made, it's good to go till you launch it hard a few times. Rough road conditions around a corner with stuck clutches could do strange things.

 

I had ring gear bolts come loose on an 8 inch Ford. Did what you described. Might check that out.

 

Okay will do thanks for the advice.

 

After you are sure there is nothing broke in the rear suspension, I believe I would find a fairly large blacktop parking lot and do a couple slow, tight, figure 8s with the car.
The idea is not to spin the tires, but to get the clutch plates in the rear end moving. That process opens up, and closes the clutch plates and allows the gear lube to get back in between the friction plates and the steel plates.

After that, I learned many years ago not to stomp on the gas pedal on curves or rough surfaces.

 

Might sound stupid, but are you sure you didn't just hit something in the road?
If it was a once only thing it could be that simple.