Hi All,

Anyone want to help diagnose this?

72' 1200 Ute with a banjo style diff. "grrr" grinding noise in the rear on the car at about 40mph. The grind has a period of about a second. The diff makes no other noise at speeds other than between 35 - 45 mph. The noise continues whether the car is coasting or under load (foot on the clutch and out of gear as well - noise continues).

What say you datsun gurus? Wheel bearings or diff bearings? I'm hoping because there isn't any other whining (its really a low frequency grinding noise) its not the pinion or crown which might be more effort.

Or am I way off? Can universal joints behave like this?

I've just checked the diff oil and its full to the fill hole and seems ok (I've yet to drain it to look for chunks of diff though ).

Just after a rough opinion as if its likely to be wheel bearings I'll do them myself - if its anything more I might just book it in...

Thanks,
Brad

Does anyone know if the 120Y diffs are a straight swap or not?

As there is a 120Y that I've been picking parts off (from a local wrecker at significant cost - any one got a 120Y for parts they want t part with in tassie?) that has a diff in it that "might" be better than the one iin the ute.

Also, I was quoted $300 for bearings in the diff providing the pinion and crown wheel is ok. Does anyone know if you can still get diff gears for these?

Cheers,
Brad

with that slow a speed of noise it would have to be in the diff centre with the slow rotation of the centre gears due to slight cornering or even a difference in tyre diameters (slight)!!!

i cant think of anything that would rotate that slowly at 40mph? maybe a wheel bearing cage?

i gues if it does it on a dead straight road with no camber then it would have to be a wheel bearing cage frequency and if there is any cornering (even slight) then it would be the centre gears

got me stumped and i guess from the lack of reply maybe everyone else too


ben

Have you tried swerving left to right to see whether the noise changes?

hi everybody, my name is coxy. i from townsville qld
Got a nice 1000 2 door sedan with a 1lt block with a 1200 head, 1200 cam, extractors and a 1 3/4 exhaust.
hope this might answer your questions.


i am to believe that the 120y centres are the same but i havnt actually needed to try it out (as i have 3 spares for mine)but was told by an old guy who lived for dattos


that noise you were talking about i had one similar to it and it wasnt till i pulled the centre out that i found out it had broken a couple of teeth off the crown and the pinion

I'll try it out.

The fairly slow period of the noise has me thinking wheel bearings. However I suppose its possible that it could be the pinion moving back and forwards a bit - but then you would think that would behave differently under power or not.

On the weekend I might pull the axles and have a look at the bearings...

How much difficulty have you guy had getting wheel bearings for these little beasties? Do you need to replace the bearing collar as well?

Thanks!

if i remember back to the day i put a new set in the 1000 there was a big chisel involved in detroying the bearing collars as there is nowhere to press against to get these off, may be different with 1200 stuff but i had to get new collars.
pretty sure they either came with the bearing kit or i got them from nissan easily

i think i may have got the kit all from nissan as it was cheaper then from a bearing shop.
either way they both will have them as they fit many cars.

if you have a welder then run a bead of weld on two sides of the collar and press off the weld. will save the chisel and therefore the swearing but will destroy the collars.
have done this many times on fwd pulsar diff bearings with 100% success.


ben

http://autos.groups.yahoo.com/group/datsunb10/