Diff knocking / Wheel hop

[HadeS]

I have been looking for some info but with no luck.

 

I have got very deep knocking noice with "jumping" rear after hard load 1st and 2nd. I have even put 2nd diff mount as my car is NA (TT swap now) but with no improvement. Problem only occure when wheels are spinning. After inspection there was no suspicion of broken mounts or bushess.

 

Any info much appreciative.

[merckx]

Problem only occure when wheels are spinning.

 

Any info much appreciative.

 

Stop spinning the wheels then.

[w41k3r]

sounds like mine when i broke my diff the teeth inside had broke of and were getting caught causing it to lock then let go kind of pull feel at the rear

[Parry_10]

Same thing happened to me mate def the teeth inside the diff, remove the diff and take the cover plate off and u will soon see

[GazB]

wheel hop

[Terminator]

wheel hop

 

In an N/A:blink:

[GazB]

In an N/A:blink:

 

Its now a tt

[HadeS]

sounds like mine when i broke my diff the teeth inside had broke of and were getting caught causing it to lock then let go kind of pull feel at the rear

 

Had the same on my open diff. Both of them been inspected and looks new.

 

Any more ideas?

[HadeS]

Is there no one with the same problem?

[Homer]

It sounds very much like wheel hop, which can be a nightmare to diagnose

 

It's very damaging to the diff and drivetrain so best to get working on the cause and doing your best to avoid it hopping for the mean time.

 

First off it's best to check the simple stuff first:

- Check all your rear suspension and subframes are torqued up correctly

- Check all rear suspension for play and ensure the balljoints are not beyond Toyota spec (you'll need to partially disasemble the rear suspension to do this)

- Check your damapers and springs are in good working order

- Check the diff backlash (not sure if this is a cause, but it was mentioned when I had the same problems a few years ago)

- Check your rear wheel geometry, tyre pressures and wear

 

What diff do you have installed?

[Terminator]

Are there differences between TT and NA rear end suspension?

[GazB]

http://en.wikipedia.org/wiki/Unsprung_mass

 

Just a guess, less or more revs may help. Less and tyres will grip and give motion, more tyres will spin and you will stand still

[HadeS]

It is LSD from N/A Homer.

[Homer]

Are there differences between TT and NA rear end suspension?

 

Some of the subframe support bars are different but the arms are the same.

 

Actually, that does raise a valid point - Hades, have you changed the rear dampers and springs to those rated for a TT?

 

It is LSD from N/A Homer.

 

Okay, much lower ratio probably won't be helping matters, but there will still be another cause for this

[HadeS]

I have put Tein Monoflex all around.

[Homer]

I have put Tein Monoflex all around.

 

What are the spring and dampers rates set for - NA or TT? Was it specified when you ordered -If not, can you dig out the spec sheet for the kit you were supplied? It should specify the spring rate at the very least.

 

I don't think this will be a single cause of the wheel hop, that's more likely arm/diff related, but it will play a part.

[HadeS]

It did the same on the stock sunspension and N/A engine so I'll have a look on arms as I know one is in pure condition.

[Homer]

If it was doing the same with the NA then something is certainly up with the arms, subframe or geometry. Are the wheels/tyres the same as before?

[HadeS]

Have swaped wheels with no success. Arms are my next stop. Ill find it sooner or later

[Homer]

Good that you've ruled out wheels already, the list is narrowing

 

Just one thing to check - have you gone through a full suspension and subrame bolt torque check after everything has settled & covered a few doezen miles AND with the car sat with the full weight on the rear wheels? (MUST be done to Toyota specs in the service manual, you might be surprised how tight/lose some of them need to be!)

 

It's only really possible on a 4 poster ramp (or improvised one that can let you get access under the car with all 4 wheels on the ground and the car level).

[Chris Wilson]

Why are the wheels spinning? Anyway, that aside, has the rear subframe got both rear diff mount bushes fitted? It needs both if you are going to drive it like a drag car. If it has both bushes it's almost certainly the dampers. Tein ones, IMHO, are utter junk and if at all old, one or both rears may be shot.

[Terminator]

Don't sit on the fence Chris, tell us what you really think of Tein systems;)

[Kirk]

Don't sit on the fence Chris, tell us what you really think of Tein systems;)

 

 

[Supra-Brett]

I would go with dampers. 16 to 17year old ones are usually worn. Mine had similar symptoms including knocking, and was corrected with new rear shocks/springs.

[little num]

Im with Chris on TEIN rubbish, i drove a car with super streets fitted and it felt horrible, all bouncy when soft then adjusted to hard was jumping all over the road.

Also i have changed my n/a to tt and have kept my n/a slipper diff with only 1 bush (original 1) and dont really have much if any wheelhop so not sure if it needs the second bush, i have yellow billys fitted with N/a springs, rear tyres are 285 - 35 - 18 R888's and i do like to spin the wheels and also still running my W58.