80 Series GXL - loud bang, no drive without center diff lock button pressed?

Submitted: Friday, Apr 22, 2011 at 16:51
ThreadID: 85802 Views:12872 Replies:4 FollowUps:9
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Hi Guys, Today my wife went to drive off in my 80 series and there was a loud bang/clunk from underneath the vehicle and then it would not drive any more?

After investigating (with the vehicle on the ground) I noticed ithe following:
Firstly with the center diff lock button NOT pressed, transfer in HIGH range:
When I put the vehicle in gear and let the clutch out, there is a notchy/almost grinding noise coming from the front diff when letting the clutch out. There is also a small oil weep from the rear seal of the front diff. The front drive shaft turns, but the wheels do not. (The vehicle does not try to move forward-or reverse).
With the engine off and car in gear, I can turn the front drive shaft quite freely by hand. I cannot turn the rear drive shaft by hand.

Now, with the transfer case in LOW range:
Exactly the same results as above only the noise is less obvious and the drive shaft spinning slower (obviously). The only difference is that the center diff-lock light does not come on (normally does when in LOW) and vehicle does not seem to be in 4WD (still not moving the wheels).

These symptons above seem to suggest that my front diff is stuffed, the part I dont understand is why my rear wheels aren't trying to turn?

Now, with the center diff lock botton PRESSED (either HIGH or LOW range):
The center diff lock light comes on as if the car is in 4WD. However, it seems to drive normally as if the car were NOT in 4WD. For eg. when driving on the bituman I have my full turning circle and the car does not feel like it is screwing the tyres around corners.
When I turn the engine off, I cannot turn the driveshafts by hand.

Can anyone please give me a hand to diagnose the problem??? I am fairly handy with a spanner but I do not know alot about transfer cases and diffs etc.
Please help save my easter...

Vehicle specs:
1990' 80 series GXL
1HZ diesel
Aftermarket Turbo (DTS)
2" OME lift

Regards, Matt.
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Reply By: Fab72 - Friday, Apr 22, 2011 at 17:07

Friday, Apr 22, 2011 at 17:07
Yup...sounds like front diff to me.

Reasons behind your locked / unlocked thingy is that with the diff unlocked, the drive is directed to the path of least resistance. In this case, the front diff where there is obviously no load due to the wheels not being driven. Press the diff lock button and all of a sudden, the rear wheels are taking up some of that drive...hence the vehicle moves.

I'd suggest taking off the front drive shaft from the transfer box, then locking the centre diff to get it to where you need to go to get it fixed, but don't see it as a get out of jail free card.

Without pulling the thing apart, sounds like the pinion gear has gone.

Good luck...let us all know how you get on.

AnswerID: 452081

Follow Up By: liveinhope - Friday, Apr 22, 2011 at 17:23

Friday, Apr 22, 2011 at 17:23
Hi Fab72,
Thanks for the quick reply...Any ideas what is involved in repairing? Would I be looking at just a new pinion gear or more? If it is my pinion gear buggered, would you suggest upgrading the front diff to a "locker" diff? If I understand correctly, the main upgrade to a locker diff is the pinion gear, is that right? (I already have the under bonnet arb compressor with the pressure switches).

FollowupID: 724748

Follow Up By: Fab72 - Friday, Apr 22, 2011 at 17:30

Friday, Apr 22, 2011 at 17:30
I guess it boils down to $$$$. If you're cashed up, then seize (no pun intended) the opportunity for an upgrade. Sounds like your half way there already.

When replacing the pinion, I always recommend replacing the crown wheel as well.

Interesting reading reddeer's reply. Haven't personally heard of that problem having those symptoms, however I must stress that I wouldn't recommend driving for any great length of time/distance without at least getting a thorough diagnosis done first. You might end up doing more damage.

FollowupID: 724751

Follow Up By: Stu & "Bob" - Friday, Apr 22, 2011 at 18:13

Friday, Apr 22, 2011 at 18:13
There is not a great deal of option when replacing the pinion, as both the crown wheel and pinion are supplied as a matched pair. Even if repairing with parts from a wrecker, use both the crownwheel and pinion from the same wreck.

My .02
FollowupID: 724765

Reply By: reddeer - Friday, Apr 22, 2011 at 17:09

Friday, Apr 22, 2011 at 17:09
It sounds like exactly the same prob i had. if your cruiser is full time four wheel you have striped the spline,s off the CV joints in the front diff at the Hub end,s if you take the caps off the ends you find that peices of metal from where it has striped.

you will need new end caps and new CV joint,s.

The reason why it drives with the diff lock in cuase you have locked the centre diff so it can drive the rear wheels.
When you take the diff lock off it means that all the drive force is going to the front and therefore not driving the rear wheels.

Exactly like when you have a open wheeler HQ or HJ holden all the drive goe,s to the open wheel.

You can drive the vehicle with the centre diff lock switched on until you are ready to fix the prob like i did.

Tom from 4wd systems in Adelaide said it doesnt do any harm.

Hope this clear it all up and explains it all to you.
AnswerID: 452082

Follow Up By: liveinhope - Friday, Apr 22, 2011 at 17:26

Friday, Apr 22, 2011 at 17:26
Hi reddeer,
Thanks for the reply, when you say "take the caps off" do you mean the take the wheels and wheel caps off? I do not have CV joints as such, I have a straight axle under the front...
FollowupID: 724750

Follow Up By: Whirlwinder - Friday, Apr 22, 2011 at 17:42

Friday, Apr 22, 2011 at 17:42
Oh yes you do have CV joints. If you didn't you wouldn't be able to turn corners.
They are in the ends of the solid axle housing.
Good luck.
FollowupID: 724755

Follow Up By: Fab72 - Friday, Apr 22, 2011 at 17:43

Friday, Apr 22, 2011 at 17:43
You're right. The 80 series has a solid front axle (not much different to the rear one).

The axles which slot into the front diff at one end, have knuckles at the other end (closest to the wheel) to allow for steering angles. These knuckles comprise of large diametre ball bearings...very similar to a front wheel drive car CV set up although unlike a regular CV joint, they don't slide in and out. They will clunk long before the fail/strip.

The short length from the knuckle to the wheel centre is splined to provide drive. Very unlikely that the spline has stripped.

I'm still leaning towards the pinion, but I'll graciously admit defeat if I'm found to be wrong.

FollowupID: 724757

Follow Up By: guzzi - Friday, Apr 22, 2011 at 17:51

Friday, Apr 22, 2011 at 17:51
The CV joints live in the "steering knuckle" of the ridgid front axle, these allow the drive from the diff to go to the wheels via the axle as the steering is turned, the short shaft from the CV then engages to the drive end plate through a spline, these wear out in the constant 4wd versions with high milage and can give the sympotoms you have.
The caps he is referring to are the drive end plates you can see under the end covers which usually have the toyota sombero symbol on them.

Dont replace the CV s with the cheap $50 chinese units from ebay, you'll be changing them again soon if you do any half way serious 4x4 work.

FollowupID: 724759

Reply By: Member - Phil G (SA) - Friday, Apr 22, 2011 at 17:41

Friday, Apr 22, 2011 at 17:41
Gday Matt,
I busted my front Landcruiser diff three weeks ago. But its a part-time 4wd, so unlocked the hubs and drove home.

To diagnose it, I dropped the oil and shined a bright torch through the drain plug hole. If its the diff, then you should have extra metal on the drain plug magnet. When you look through the hole and rotate the prop shaft. you can see if the crownwheel teeth are intact. If the diff looks OK, I'd proceed to take out the CVs.

I removed the diff myself and took it to a diff repairer. It needed new crownwheel and pinion (costs up to about $1000 for genuine), a bearing kit (about $250) and in my case needed a new flange (about $120). Labour from the diff repairer was $440 - this cost a little more because I had an ARB locker. I spent a lot of time removing bits of metal from the diff housing, and while everything was apart, regreased the CVs and wheel bearings.
AnswerID: 452086

Follow Up By: liveinhope - Friday, Apr 22, 2011 at 18:14

Friday, Apr 22, 2011 at 18:14
OK guys, I have just taken the fill plug bolt out and surprisingly I cannot see any noticeable metal shavings inside the plug. I was also able to swipe my little finger on some of the internal faces and again no shiny fragments of metal. I had my young bloke turn the front prop shaft while looking through the fill hole and all the teeth looked intact. I will take the caps off the end of the axles tomorrow (more light, less beer) and see what I can see then.

Thanks so much for all your replies, I will post follow up as I find more info.
FollowupID: 724766

Reply By: Big Woody - Friday, Apr 22, 2011 at 18:30

Friday, Apr 22, 2011 at 18:30
Hi Matt,

Being the 1990 model, as mentioned above it is most likely that your axle spline has stripped at one end or the other. Most seem to go at the "CV" end but my 80 series stripped the spline inside the side gear of the diff.

All it cost me was a new side gear at $85 and a 2nd hand axle from the wreckers cost me $60 and a days work and it was all good again.

The early 80 series had splines that didn't mesh as much as the later models which is why they struggle with backlash issues. The spline on the other axle on my car was also strecthed a little but I put it back together as it was but I am sure that it was also contributing to the backlash.

If you are not mechanical and need to pay someone to fix it you could easily be up for $1000 as you might as well fit new swivel hub kits and wheel bearings while it is all open.

AnswerID: 452095

Follow Up By: Olsen's 4WD Tours and Training - Sunday, Apr 24, 2011 at 06:42

Sunday, Apr 24, 2011 at 06:42
FollowupID: 724839

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