Outer Limits 4x4 Board

g'day fellas
i have a 93 wt sierra and recently went to dropzone (mud mania!!!) and was stuck in a big puddle for atleast half an hour in which the rear diff was completly submerged..after driving for a few days the car started to drive REALLY noisy...it was only wen i put load on the motor/drivetrain..wat would happen right was say your driving in gear but with no throttle,then u put your foot on the accelerator and suddenly a really loud noise would occur...almost a humming noise,but really loud.I presumed it was the diff oil was contaminated... ( i was running 31's for a few weeks previous and during the incident but with no abnormal noises-if that makes a difference???,with no aftermarket gearing- but im prtty sure it wasnt the tyres,cos the noise started a few days after i was stuck in the puddle) so i decided to change both front and rear oils (aswell as extending the breathers!!!) the front diff oil was very clean-almost looked new.. but yes the rear was very dark... but there is still the same noise,it has quietenend down abit but isnt the same?? could it be the motor or box
??i havn't gotten around to changing box oil yet as ive bin away the past month..but just wanted to see if anyone can help???
cheers

Once there's a noise changing the oil won't make it go away - it's like repainting a cracked wall and expecting the crack to go away.

I'm afraid you've most likely trashed the diff. Some mud will have got in there and it will have carried some grit with it. That grit will have started to wear all the contact faces - bearings and ring and pinion, and that's the source of the noise.

The cheapest option will be to track down a replacement WT rear diff centre. This will be far cheaper than rebuilding yours.

It's unlikely any water will have made it's way into the transfer or gearbox, unless the water was very deep (i.e it was in inside the car) but I'd change the oil in them now anyway.

Steve.

yer.. the water did get in the car,but it was sitting on the diffs and just leaning to 1 side and thats how water got in ..im pretty sure..
so wat would i be looking at to pay 4 a replacement centre? wat would be most likely to happen if i left it?:D
cheers

zookkid wrote:yer.. the water did get in the car,but it was sitting on the diffs and just leaning to 1 side and thats how water got in ..im pretty sure..
so wat would i be looking at to pay 4 a replacement centre? wat would be most likely to happen if i left it?:D
cheers

it will get louder over time .. might last years, might last months .. depending on the damage.
When you too the oil out, did it have metalic flakes in it ?

Normally everything will start getting loose. You'll get lots of blacklash and the noise will get unbearably bad. You'll likely get it fixed before it acutally fails because you can't stand the noise any more.

However, if you could somehow put up with the noise (possibly only by being deaf), eventually the gear contact pattern will wear badly due to the looseness in everything and you'll end up with gear failure due to all the load being borne at the edges of the teeth.

Oh, you should be paying $150-$250 for a replacement centre from a wrecker.


Steve.

i would put money on its the bearings on the cluster gear on the transfer not the diff...

they go alot faster..

just my opinion..

kinda hard to check withough some one who knows what they are looking at..

Gwagensteve wrote:
Oh, you should be paying $150-$250 for a replacement centre from a wrecker.


Steve.

more like 350-400 in my experiance

Ill take your virtual money and raise you a neverending packet of tim tams it's the back diff.

It got quieter when he changed the oil in the diff...

Steve.

Gwagensteve wrote:Ill take your virtual money and raise you a neverending packet of tim tams it's the back diff.

It got quieter when he changed the oil in the diff...

Steve.

posibly.. could have been the placebo efect of doing it...
it could be both...

Gwagensteve wrote:Normally everything will start getting loose. You'll get lots of blacklash and the noise will get unbearably bad. You'll likely get it fixed before it acutally fails because you can't stand the noise any more.

However, if you could somehow put up with the noise (possibly only by being deaf), eventually the gear contact pattern will wear badly due to the looseness in everything and you'll end up with gear failure due to all the load being borne at the edges of the teeth.

Oh, you should be paying $150-$250 for a replacement centre from a wrecker.


Steve.

x2
my rear diff is shagged due to mud /water in it when i brought it ... due to pitiful little breathers on it

its got ALOT of slop in the rear .. rotate 1 wheel almost half a turn with out the other one turning

I'm just swapping the whole rear diff over since there is belief the wear has damaged the axles as well

Gwagensteve is right about everything. i just did the same thing to my rear. (submerged it.stuck for 2.5hrs). i changed the oil about 1 week later (1week too late if you ask me) and it made it marginally quieter. the oil was brown and looked like a choc milkshake.

its now july and my diff is soo bad, its barely driveable :( . so i'd say you got a couple of months till you need to change it.

ohh, anyone in melb got a diff centre, pm me please

if you were considering an air locker at some stage now you have an excuse =P haha

ok maybe ill just look at a replacement centre... no there wasnt any metal flakes,jus wat was tuck to the magnet-the tiny particles,thanks heaps for the help fellas

i was thinking about a locking diff or something along those lines? what would you guys suggest including price,driveability and relaibility?
cheers jez

Do a search - there's heaps and heaps on lockers on here, but price goes from (almost) free for welding, mini spool, lock right, detroit, airlocker.

Price = Welded
Reliability = Mini spool
Driavbility = airlocker

I run mini spool rear and airlocker front.

Steve.

fark jus checked out wat i mini spool was? how will it drive after?? will my tyres surive??

zookkid wrote:fark jus checked out wat i mini spool was? how will it drive after?? will my tyres surive??

You tyres will wear quicker. It will drive different, the front will slightly push on corner entry, and on exit you can provoke oversteer if you are not careful, though usually on wet roads. Not enough power in the dry. Turning tight corners or carparks will get some tyre noise, and speed up the rate of wear. You may also suffer from axle spline rotation, though that is more related to any locker, not just mini-spools. If you rig is an off-road (or at least not a daily driver) then a mini-spool is a pretty practical way of getting the rear locked on the cheap. True welding is cheaper, but if you dont like it you cant just swap back.

Layto....

Gwagensteve wrote: The cheapest option will be to track down a replacement WT rear diff centre. This will be far cheaper than rebuilding yours.
Steve.

wouldnt he be better off with NT centers (front and rear) or changing to Vit centers? fair enough it will be more than standard WT centers.. but for the $ and the reduction worthy no?

just curious...

NT to WT is only about 5% = 175rpm @ 100kph - not worth buying another centre for IMHO.

unless zookid tracked down some 4.6 vit gears from a carby auto he'd have way too much gearing for the road with 31's on it, adittionally, he'd be up for 2 centres and 2X gear setups - a lot more $$ and similar to a set of transfer gears.

Steve.

no i havent bought anything yet
will prob just get a orig. replacement centre,cant afford a locker

If I put a mini spool/welded centre in the front diff,will it lock the wheels on unlocked hubs?or will it only lock the wheels when the hubs are locked?

zookkid wrote:If I put a mini spool/welded centre in the front diff,will it lock the wheels on unlocked hubs?or will it only lock the wheels when the hubs are locked?

When you unlock/lock your hubs, you are effectively disconecting that wheel from the axle. So once unlocked any locker ceases to act on the wheels.

Layto....

kewl,thought so jus wanted to check.
cheers!

zookkid wrote:fark jus checked out wat i mini spool was? how will it drive after?? will my tyres surive??

drift sierra mate.lol

haha drift-spec zook

* I know spools/welded diffs are illegal on the road*

A spooled/welded diff is, IMHO a lovely thing to drive on. Yes, there is understeer on the way in to a corner, but on the way out....

What makes them so nice is that on a low traction surface - wet road, dirt etc - the car will start to drift, and it then becomes very controllable on the throttle and much of the slow steering response you get with a sierra seems to disappear - you can really play with the weight transfer and make the car dance. You'd be surprised. Back off, and it comes back and bites again.

I'll admit I'm in a LWB with pretty good caster and very narrow tyres, so it's easier to catch, but it's pretty good fun holding a car in a drift for 50 meters or so in high second on a wet 2WD dirt road... It's priceless.

Front welded diffs suck. The steering sucks. It's hard on CV's, and generally a PITA. You'd regret it.

Steve.

A spooled/welded diff is IMHO a horrible thing to drive on.
Try it, but you will eventually get sick of its hadling charactaristics ( or lack thereof ) and it turns what could be a nice vehicle to drive daily into a PITA. Nevermind all the other load and tyre issues. just my 2 cents.

joe.

I will add my 2 cents, a spooled diff on a low powered car with big tyres is a PITA, a spool on a high powered car can be fun. Still I'd prefer any other form of locker over welded/spool on a road car.

I did say I'm on narrow tyres. The lack of lateral grip definitely helps.

Still, It is a viable option for the rear IMHO. We've had club members that have run welded for years.

Steve.

Yeah hence why I said on wide tyres, wheelbase and tyre width aswell as power really makes the difference. If you run stocko width road tyres druing the week then it's a definately good option, more so on a LWb