13 replies to this topic

[Adcuz]

I was pulling up to some traffic lights earlier today when the car came to a faster stop than I was expecting. The front wheels locked up and after that the car was unable to move away, it kept stalling as if the brakes were still on. Next I tried reverse, same issue. There is about 1 revolution of the wheel slack if you rock it backwards and forwards. It goes into gear fine with the engine running.

Any ideas? I suspect a diff issue, but any words of wisdom would be appreciated.

[xBR4DLEY]

Yeah I'd say diff aswell but not too sure mate , I'd wait for someone elses advice. It sounds abit like gear selector pin coming out but then you would be able to move it in neutral?

[Adcuz]

Gear selector is fully in-tact, I can select all gears including reverse and move about 1 wheel revolution until it just hits a "wall".

[xBR4DLEY]

Yeah thats what I was trying to get at , if it was gear selector you would be stuck in gear but you can , so sounds like diff , maybe PM guessworks?

[Ethel]

Jack the wheels off the floor and try turning them by hand.

[Adcuz]

Hey Ethel,


I've just done that, the wheels turn opposite ways as they should when turned, however they have a lot of slack and the rotation feels a bit rough/bumpy. This was in neutral. Any ideas?

[Big_Adam]

I've just done that, the wheels turn opposite ways as they should when turned, however they have a lot of slack and the rotation feels a bit rough/bumpy.

If you mean the wheel opposite turns the opposite way ... that's the diff planetary gears doing their job.

[Adcuz]

I've just done that, the wheels turn opposite ways as they should when turned, however they have a lot of slack and the rotation feels a bit rough/bumpy.

If you mean the wheel opposite turns the opposite way ... that's the diff planetary gears doing their job.

Yep, that's why I said "as they should". Weird problem, I guess I'm just going to have to rip it apart and see what's going on.

[dklawson]

Before you take anything apart, put the front back on stands, apply the brakes, and quickly get out and try to turn the wheels. If the wheels feel locked up after this, and if your car is older, consider replacing the flex lines to the brakes on each wheel. Old hoses can collapse on the inside and still look good outside. This creates a check-valve situation which keeps the brakes locked on until the pressure slowly bleeds out.

[Ethel]

The slack could be in the CV joints but you would see that by watching if the pot joints with the wheels. The "locks after one wheel revolution" does suggest the diff, but it can't have totally fallen to bits if the bevel gears will turn the opposite wheel.

After scratching my head I reckon it would take 2 full turns of one road wheel, with the other on the ground, to turn the crown wheel once.

[Adcuz]

Before you take anything apart, put the front back on stands, apply the brakes, and quickly get out and try to turn the wheels. If the wheels feel locked up after this, and if your car is older, consider replacing the flex lines to the brakes on each wheel. Old hoses can collapse on the inside and still look good outside. This creates a check-valve situation which keeps the brakes locked on until the pressure slowly bleeds out.

I can tell it definitely isn't the brakes as you can see the engine move when it gets to the end of the available travel, so the thing that's locking the wheels is definitely at the engine end.

The slack could be in the CV joints but you would see that by watching if the pot joints with the wheels. The "locks after one wheel revolution" does suggest the diff, but it can't have totally fallen to bits if the bevel gears will turn the opposite wheel.

After scratching my head I reckon it would take 2 full turns of one road wheel, with the other on the ground, to turn the crown wheel once.

The thing is, during the "slack period" the pot joint on the side I am rotating is still moving, so the CVs are sound.

I hope the rain keeps away this weekend.. time to do my 3rd engine removal in as many months.

[Ethel]

Sounds like it, at least if the diff has gone it does sound like you've got off lightly.

[Adcuz]

Indeed! Luckily I have a spare gearbox in the garage.

Cheers for the help

[Adcuz]

UPDATE!

Just had the engine off the gearbox, it's the usual suspect of a snapped diff pin! I reckon if I'd been going any faster the housing would've exploded. Time for an X-Pin diff