Bypass hose on 79 series
Submitted: Wednesday, May 09, 2007 at 22:10
ThreadID:
45286
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Member- Tony C
After reading posts (44014,43605) on this site about gearbox and related issues with the 79 series Landcruiser i fitted a bypass hose, hopefully before any damage has been done to the gearbox.
Before undoing the drain plug on the transfer case i noticed oil had been leaking around the case and when the filler plug was undone the transfer case was way overfill and not much oil at all in the gear box.The oil leak was from oil dribbling out the breather on the transfer.Iam having a new and stronger output shaft and seal fitted next week.
Can anyone please explain how this bypass hose works? With the transfer case at a lower level than the gearbox i would have thought with a leaking seal the oil would flow into the transfer case and find its level in the hose instead of pumping back up to the gearbox as it seams to do.With the transfer case vented i cant see how any pressure could push the oil back.
Reply By: Member - Doug T (W.A) - Wednesday, May 09, 2007 at 22:22
Wednesday, May 09, 2007 at 22:22
Tony
I notice you said [ undoing the drain plug on the transfer case ] You didn't put the hose to the drain holes did you , the hose should be fitted to filler holes,
Doug
AnswerID:
238950
Follow Up By: Member- Tony C - Wednesday, May 09, 2007 at 22:36
Wednesday, May 09, 2007 at 22:36
Doug,
I made a mistake there. Was fitted to the filler holes.
Tony
FollowupID:
500006
Reply By: Steve from Top End Explorer Tours - Wednesday, May 09, 2007 at 22:28
Wednesday, May 09, 2007 at 22:28
Hey Tony
Apparently It's only you and I that have this problem that doesn't exist.
The hose that doesn't work forces the oil back to the gearbox through pressure that doesn't exist.
I am the only person that has had this problem in the past an used the by pass hose that doesn't work to my favour.
Cheers Steve.
PS did I mention that I have a gearbox pulled apart in my shed that this problem didn't happen to.
AnswerID:
238953
Follow Up By: Chris & Debbie - Thursday, May 10, 2007 at 19:28
Thursday, May 10, 2007 at 19:28
Steve
Yes this problem does exist and the hose is a common fix, the only thing i dont agree with you on is the pressure bit it. It's just rely's on normal gravity feed, the oil leaks into the transfer case then drains back to the gearbox or a least that is what i have seen.
Chris
FollowupID:
500158
Follow Up By: Steve from Top End Explorer Tours - Thursday, May 10, 2007 at 19:36
Thursday, May 10, 2007 at 19:36
Hey Cris
That would mean you have seen fluid run up
hill!!!! LOL
The fill plug on the transfer is below the filler plug on the gearbox.
Cheers Steve.
FollowupID:
500162
Follow Up By: Member - Davoe (Nullagine) - Thursday, May 10, 2007 at 19:56
Thursday, May 10, 2007 at 19:56
you are correct Steve It definitly does not work I had one of those wast of space hoses so i can confirm it doesnt work> I would periodically drain the TC and refill the earbox
FollowupID:
500165
Follow Up By: Steve from Top End Explorer Tours - Thursday, May 10, 2007 at 20:10
Thursday, May 10, 2007 at 20:10
Hey Davoe
I actually said it works, I used one on an old 75 series years ago with expected results.
As for periodically draining I don't recommend this as when my 78 series box let go it happened with in 250kms.
Cheers Steve.
FollowupID:
500172
Follow Up By: Chris & Debbie - Thursday, May 10, 2007 at 20:42
Thursday, May 10, 2007 at 20:42
Hi Steve
Maybe I needed to explain it better...the oil doesnt run up
hill, the transfer case actually ends up over full to the level of the gearbox level plug. you cannot get any pressure build-up as there is a breather.
Chris
FollowupID:
500178
Follow Up By: Member -Signman - Wednesday, May 16, 2007 at 09:35
Wednesday, May 16, 2007 at 09:35
G'day Steve
I don't know if you're advocating that the gearbox/transfer case bypass hose works or not?? As Pauline once said "please explain".
Does the transfer case pressurize and force oil into the gearbox- with the hose allowing it to flow back?? Or does the gearbox 'leak' into the transfer case and the excess flows back up ??? to the gearbox??
I have heard both theories- but can't ascertain which one is correct.
You assistance is appreciated !!!
FollowupID:
501255
Follow Up By: Steve from Top End Explorer Tours - Wednesday, May 16, 2007 at 10:28
Wednesday, May 16, 2007 at 10:28
Ok
The seal does fail leaving oil to leak from the gearbox to the transfer, sometimes slowly sometimes quickly as happend to me.
YES this does happen to a 78/79 series gearbox.
Does the hose transfer oil back to the gearbox yes, after what Chris said i'm not sure how it happen although I do know for a fact that it works.
Cheers Steve.
FollowupID:
501272
Reply By: hiab - Thursday, May 10, 2007 at 00:24
Thursday, May 10, 2007 at 00:24
`dont panic, if you have checked levels after driving, aeration occurs in the oil, which gives a false reading. eg. seems overfull, but isnt, give time to settle. then
check. i know most will disagree, the later 79 does not need a hose as they are a sealed separate entity.
AnswerID:
238983
Follow Up By: Steve from Top End Explorer Tours - Thursday, May 10, 2007 at 18:15
Thursday, May 10, 2007 at 18:15
Hiab
Fact # 1 The 78/79 series gearbox does leak between the gearbox and the transfer, I have had this discussion with you before.
Fact # 2 The hose does work, exactly the way I explained in the above post.
Question # 1 If the seal doesn't leak, how did the oil in my gearbox transfer into the transfer case.
Question # 2 How did this happen? After draining the oil out of the (over full spewing out the breather) transfer case, I went to drain the oil out of the gearbox surprise surprise no oil.
You have more chance convincing me that Santa Clause and the Tooth Fairy exist.
Steve
FollowupID:
500136