Gearbox / Transfer case filler plug holes.

Submitted: Tuesday, Feb 07, 2006 at 08:39
ThreadID: 30509 Views:2835 Replies:8 FollowUps:1
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Hi. Investigating oil leaks under my 1985 BJ73 Landcruiser, I note that a previous owner has removed the plugs from the filler holes in the gearbox and transfer case, and connected them together via a plastic tube.

Both the caterpillar clips used to attach the tube were loose so this was a source of oil drips, easily fixed. But the tube is vulnerable to being snagged by branches or rocks, and I'm inclined to restore the original plugs.

HOWEVER someone must have gone to this trouble for a reason. Does anybody know what it might be, and if it's a good idea?

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Reply By: Member - Davoe (Widgiemooltha) - Tuesday, Feb 07, 2006 at 08:49

Tuesday, Feb 07, 2006 at 08:49
yes the internal gasket/seal is prone to failure and it alows some kind of exualization of oil. I found it a dismal failure as oil from my Gearbox was getting into my T/C which is lower so the T/C would overfill and start leaking. Every 10k i would drain a bit from the T/c and top up the gearbox. As you said the equilizer pipe unions were also prone to leaking
AnswerID: 153544

Reply By: Member - Stephen M (NSW) - Tuesday, Feb 07, 2006 at 08:50

Tuesday, Feb 07, 2006 at 08:50
Hi there Pj73, they do this because I think for memory its the transfer case that blows an internal seal an throws all the oil over to the gear box (or vise versa) leaving the transfer case starving of oil, common problem on the hilux's too just a cheap way of fixing it save pulling the transfer case etc out this way keeps oil equalized between box and transfer case, your probably shaking your head about now but dont bother cause this was done many a times at toyota as well but they use to make up a welded pipe to suit with proper flanges etc. Regards Steve M
AnswerID: 153545

Reply By: theshadows - Tuesday, Feb 07, 2006 at 08:55

Tuesday, Feb 07, 2006 at 08:55
This is a standard after market fix bypass line for a blown transfer case seal. This is very common on LC models up to the 80 series. the seal of your transfer case is blown and it pumps th oil up out of it into your gear box. This tube allows the oil from the over full gearbox to flow back to the transfer box and stops it from running dry and blowing up.

Go to pirtek and get a half inch line , 2 90degree bends and 2 adapter plugs for your gear box. These are all off the self items and quite cheep. It will cost you about $90. Beter still they are quite damage proof and look professional.

When you connect the new line up make sure all of the line is below the gear box filler level for it to work properley.

AnswerID: 153546

Reply By: PJ73 - Tuesday, Feb 07, 2006 at 10:44

Tuesday, Feb 07, 2006 at 10:44
Thanks, all, for the info. I think that even if I were to fix the seal, I'd like to have the tube (Pirtek standard) in place for the future date when the seal goes again.

AnswerID: 153572

Reply By: Kiwi Ray - Wednesday, Feb 08, 2006 at 11:40

Wednesday, Feb 08, 2006 at 11:40
Hi PJ. I would also check that the two breather tubes for thr transfer abd gear boxes are clear.
Oil seals on these shafts should last for a long time if they are fottrd properly and there is no pressure behind them.
you also do not want an EP oil to get into the gear gox.
AnswerID: 153811

Follow Up By: PJ73 - Thursday, Feb 09, 2006 at 09:08

Thursday, Feb 09, 2006 at 09:08
Thanks, Ray will check breathers. What is 'EP oil'?

FollowupID: 407923

Reply By: Kiwi Ray - Thursday, Feb 09, 2006 at 09:38

Thursday, Feb 09, 2006 at 09:38
Hi PJ. The oil in your diffs and transfer case has an addative called an extreme pressure addative, it makes the oil more slippery in basic terms. This also includes the oil for limited slip rear diff. The gearbox oil is a relatively plain oil, if the EP type oil was put in you gearbox it would prevent the syncro hubs working correctly making it very difficult to change gear. See other threads on gearbox oils. There are two oil seals one on the rear of the gearbox and one on the front of the transfer box, you may wish to look at both while the trans is split. Make sure that a good anti sieze paste is used on the spline when reassembling.
AnswerID: 154025

Reply By: PJ73 - Thursday, Feb 09, 2006 at 13:04

Thursday, Feb 09, 2006 at 13:04
Ray, this is good info. It opens a bit of a can of worms for me though, and I'm sure you didn't expect to get into a whole bunch of queries when you offered your advice.
However, here's what bothers me. If the oil for Transfer Case and gearbox is incompatible, how can it be that the tube addition is such a well known after market fix? Wouldn't all the people who fitted one find that their gears became difficult to change? (Incidentally no probs yet with the gears on mine).
AnswerID: 154063

Reply By: PJ73 - Wednesday, Feb 15, 2006 at 16:08

Wednesday, Feb 15, 2006 at 16:08
Hi, thought I'd round out this string and say what I ended up doing. I called the Royal Automobile Association here in Adelaide and took advantage of their technical advice service (for members). Their rep (Mark) looked up the oil specified for the gearbox and transfer case of my model and it was the same. He hadn't heard of the extra slippery oil theory and said that he'd recommend the bypass pipe even if the seal was good, because when it does 'go', the first some people know about it is when their transfer case blows up. That's if they're not lucky enough to have it spotted during a service.
So I'm looking in to the Pirtek steel pipe mentioned earlier to replace my vulnerable plastic one.
Thanks to all for their input.

AnswerID: 155163

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