80 series transfer oil seals

[Rob]

How hard would it be to remove the T-case as a complete unit?
Seems this job will be a bit easier in my shed than on my driveway.
My neighbours already look at me funny as it it...

You take the rear extension housing off and then you can work on it on a workbench.

 

[BRE Fabrications LTD]

Would this enable me to change the front output bearing and seal too?

 

[Rob]

No as the front seal is still on the truck. I do not know have to remove that one.

 

[Chris]

Isn't the front one a more conventional arrangement? Nut, flange, shaft, seal? I haven't studied the diag on that one yet as it's not leaking.



Chris

 

[BRE Fabrications LTD]

No as the front seal is still on the truck. I do not know have to remove that one.

Ya, i figured it would still be on the truck... bscene-birdiedoublegreen:

I stopped being lazy and had a look at the FSM, seems to be a similar setup to the rear, remove housing and disassemble on the bench...

 

[Roger Fairclough]

I suggest you remove the dust/dirt shield---it's a gentle prise off job---and then you can polish the surface of the output flange where the seal touches.

Roger

 

[BRE Fabrications LTD]

What would be best to polish it with? 1000 grit sandpaper or would rubbing compound do the trick?

 

[Roger Fairclough]

Depends on the state of the metal. You will normally find the inner end is ok as it is inside the casing. Then you may find a shallow polished groove where the seal lip has been running and then a lightly rusted part under the dust/dirt shield. I would remove the rust with a rotory wire brush---I have one mounted on my grinder---followed by wet and dry loaded with light oil. I use 1200 grade. The idea is to blend the edges of the groove into the surface of the flange. Any light pitting left on the section under the shield will not be a problem as it should not interfere with the new seal as long as you correctly set the seal into it's housing. Once the new seal is in place use grease to lubricate it and the flange when you re-assemble.

Roger

 

[stevoyorke]

Good reading as I am getting a leak out the rear output shaft which involves taking the casing apart to get down to the seal!! How long would job take? I use the car daily!! Cheers

 

[Andrew Prince]

Depends how handy you are with the spanners, Steve - and whether you have the knack of getting the circlips out quickly and without damage
You could probably do it in a few hours if you really knew what you were doing - for people like me it's more like a full day bumbling around and stopping to check that I'm doing the right thing.

You'll need to let the RTV set for a while before refilling with oil and driving off - I guess a couple of hours for that to be safe.

 

[Chris]

Seals and pliers on their way. I'll swap the rear seal out, but pretty sure for now I will change the whole rear extension housing and then put the new seal in at my leisure. No pressure then. Seems a daft way to have to do a seal. Rather a waste of oil too. I'll probably lift the front on ramps and let what bit spills out of the rear diff go all over the place (it always does) then just top it back up when I've done. Centre box is going to need a full drain though.

When I do the TC seal, I'll try and capture it on here for a sticky. It sounds as though there is going to be a run on 90311-58008 at the dealers!

Chris

 

[AndyCook]

looks a right pain compared to the 90-series - seal on order for mine!
and i was annoyed I will have to drop the whole rear prop
not just the front end (due to bolts being set in flange at front...)

 

[Roger Fairclough]

[quote

You'll need to let the RTV set for a while before refilling with oil and driving off - I guess a couple of hours for that to be safe.[/quote]

The space or clearance that RTV takes up is so small that 10 minutes will suffice for it to set.

Roger

 

[Jon Wildsmith]

pretty sure for now I will change the whole rear extension housing and then put the new seal in at my leisure

I never had to do this job on my 80 but have done it on my 100 and they're similar - there are shims you may have to change if you swap parts between complete box's. I just replaced the seal on the one that came off instead of swapping them over.

 

[Chris]

Really Jon? I would have though that the extension housing was a self contained unit - no? I always heed your advice even though sometimes I appear to question it. You know that. I wouldn't ask questions if I already knew the answer.

I will look at the FSM in some detail when I get chance, but I really did see it as a swap out option. There are certainly shims etc inside the extension, that's for sure. But clearly I'm not changing any of those, just moving them and putting them back.


Chris

 

[Jon Wildsmith]

AFAIK the front housing is not shimmed but the rear has a shim on the oil pump and another on the output shaft but I never actually messed with an 80 one ...

 

[Jon Wildsmith]

Also, when I did mine I noted the new seal had a taller lip for a better fit into the back of the dust flange and wondered if they would also fit an 80 ... anyone got a picture and dimensions of an 80 seal?

 

[Chris]

I will have Jon, once the lazy Postie has been.

Chris

 

[Chris]

Rob, couple of questions..

When you stripped the rear housing did you have to remove the oil pump mechanism or can all that stay in situ and did you have any difficulty driving out the main shaft extension and getting it back in again? The FSM indicates that it is pressed in. Did you just club it expertly with a large hammer?

Chris

 

[Andrew Prince]

I think you can leave the oil pump alone from what I recall.

I pressed the shaft out and back in again but it took very little force (i.e. it basically fell out as soon as there was some pressure). A few judicious taps with a rubber mallet should knock it free quite easily. Likewise when you're putting it back together, tap away until it's home. Not much force needed at all. The biggest challenge is avoiding damage to machined surfaces.

There are some good write-ups/tutorials on this job on MUD. I don't have the links to hand unfortunately but can dig them out tonight if you're still interested?

Cheers,