ok so i got my car back on the road after a 7 month hiatus., and now i notice that when i drive the car i notice what feels like mad tire hop even when the tires are not burning out. if i accelerate too fast or take a corner too fast i notice it does this.

so i went under the car to investigate whats wrong. i searched around first for "broken diff mounts" and read up about that so i jacked th car up and when to searching
i discovered that my mounts are all good,. i did all the "tests" people on here do to determine if its busted. i grabbed the axle and gave it a twist, and there appears to be slack in it. doesn't seem normal:/ also when spinning one tire by hand the other tire stays neutral. it used to spin before like this.,

sound like a broken rear diff?

 

Not an expert or some may say I'm talkin out my *** but I've seen some cars with broken Diff and they dont move period...

 

^^^
he is right, a broken diff will not move.

So when you accelerate, the rear of the car hops?

 

Of course you know, a sheared tooth/teeth in the rearend will still allow said rearend to move.... But it will jerk. A friends Camaro had a few sheared teeth in his, wasn't noticeable too much at cruise, but if you got on it, it was all funky.

Curious and stupid question. Do you have any high-spots/bubbles on your tires? Or any significant mud buildup on the inside of your rims?

 

no bubbles or mud. although i did notice tht one of my tires is a different size than the other 3. and its one of the rear ones. this may be the reason behind the hopping in the corners but i dont think that would be why it hops in a straight line. or the clunking when i get on it. oh well i guess ill rock it till it goes out. im putting a lsd diff in there this fall.

 

Well if it when getting on it hard or when shiftin than that is your diff. mount it hard to tell but if you put the car up on jack stands (all 4 corners) go under the diff. and push up on the front where the drive shaft connects to the diff. If it moves easy (pushing up on it 10lbs of trust of force) and look for the rubber bushing to separate when doing it than you'll know it's the Diff mount. While it's up in the air check your tires you might have a blister in your tires and also check to see if all bolts in the rear suspension is there cause if not that can also cause your problem.

 

when you swap the diff. I suggest replacing

1. rear subframe mounts
2. all 3 diff mounts
3. Install new diff.



THis should take care of all clunking on the rear end.

 

Different sized tires (different diameter?)

Would this not cause some serious issues (in a limited slip diff), with one wheel spinning faster then the other? (smaller diameter would have to spin more times, to keep up with the larger diameter)

I would highly recommend tires of the same size.

 

differant diameter tires on the rear is hard on your diff. it would wear out the internals of your diff, i see it all the time at work, and it would create a "hop" like feeling , if your car vibrates its your rear weels, if your steering wheel its your front wheel.

 

would this also apply to an open diff? cause the way you worded that it seems to be set towards a lsd. which i do not have.

alright well i already checked the rear diff mount. its still solid. and no blisters in the tires. it feels as if whatever the issue is its coming from the diff itself. like the pumpkin.

and it seems to make the "hop" like feeling that powerhour is talking about.

 

Of your car is on stands get some string and mesure your back tires ad if they are out u can swap the fronts to the back for now, unless if u can get some new tires, I don't have any experiance on an "open diff" at my shop we work on only trucks and they all have LSD, but if u Pull the cover off and drain the oil and look at the gears it should be obbouis of there's and sheering of the gears or irregular wear and post pics! If ya don't know I'll be able to help you out! That way u can elimnate if it's comeing from the gears inside, plus you'll get fresh diff oil which is nice

 

But check your tires first!

 

You can also try before you pull the diff cover off is when both the rear wheels are off the ground to spin one side and if the other wheel spins the opposite way ur diff "should" be fine and if only one wheel spins then there is a problem with your diff. Hope any of this helps!!

 

Yes - still hard on an open diff, not as bad, but it's still causing the diff to constantly be spinning the spiders so one side can spin at a different rate, as if you were always going around a corner (NASCAR!). That generates extra heat and wear. It's part of why if you have to run a limited service spare on a FWD, it's recommended you not use it at the front, even if the flat is there - remove a rear, put it at the front, put the donut at the back.

Drain your diff fluid, see if there's any metal particles in it, or if it smells burnt.

 

what do you mean by "measure your back tires"

and also you cant take the cover off and look at the gears. its like a ford 9 in. everything comes out the front. and i really dont want to have to go thru the troulbe ot doing that to only find out its trash. i'd much rather just swap it out.

 

well i cant make it to the store right now to get more gear oil to swap it but i pulled the upper plug and dipped my finger in to verify there was oil in there and it smells burnt. thats one of the worst smells

 

get some string and wrap it around each tire and lay it out flat and measure it to see if theres any differance

 

burnt is not a good smell lol was it fairly dark, or griddy?

 

well i kow one tire is physically different size. like the numbers on the side wall is different than the other three.

i couldnt really tell what color it was. i just had enough to cover my finger tip and to know it stinks.

 

try putting both same size tires on the back and take her for a spin see if theres and change, cuz that could be your problem

 

well i just read where you said something abour raising the rear end and spinning the tires. only one will spin at a time. doesnt matter which one you turn or what way you turb it