HZJ 79 series ute Gear box and transfer case.

Submitted: Sunday, Mar 25, 2007 at 07:14
ThreadID: 43605 Views:25814 Replies:8 FollowUps:19
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Hi,
I just did a check on the oil level of my 79 series 4.2 gear box and transefer case.
I found that the gear box was down 2 inches, and the transfer case was full almost to the brim. so i am guessing that there is a leak between the 2 boxes.
Is this a common problem? and also what cost would there be in repairing them?
Can i do something like use the same oil type and just keep an eye on the levels?
Regards Chris
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Reply By: Wayne (NSW) - Sunday, Mar 25, 2007 at 07:48

Sunday, Mar 25, 2007 at 07:48
Chris,

In some of the Toyota gearboxes if the seal between the gear box and the transfer box leaked, oil would be pumped from the transfer box to the gear box.

Now if you look at the transmission the transfer box is lower than the gear box and you would think that the oil would run from the gear box down to the transfer box. However it is pushed up because of pressure in the transfer box. The transfer box does not have a breather, unlike the diffs and gear box.

The transfer bow would empty and the gear box would fill.

Rather than pull the transmission out just to replace a seal, a hose was fitted to the filler plug of the gear box and also the filler plug of the transfer box. This allowed oil to flow between the boxes and even out. I got a hose from Pirtek in Penrith.They new what I wanted, had the right fittings, made it up on the spot and cost $6o.

You are saying that the oil level in the gear bow is down and the transfer box is up. This is opposite to what should happen, but the oil transfer problem that I have experience is with the 75 / 60 and some 80 series vehicles.

I would top up the gear box and drain the transfer box until you have the correct level. The transfer should be easy, just let it flow out the filler plug until is stops leaking, and fill the gear box until the oil just leaks out of the fill plug. Check the levels again in about a week. If there is a difference in the levels, one up and the other down, try the equaliser pipe.

Wayne
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Follow Up By: Member - Steve T (NT) - Sunday, Mar 25, 2007 at 08:29

Sunday, Mar 25, 2007 at 08:29
Hi Chris

I have a gearbox that now needs a rebuild because of this problem, same deal oil drained between leaky seal.

Get that hose tomorrow as I checked my levels, I drained one topped up the other and the next day the gearbox drained into the transfer and the gearbox is now in pieces it took 250 kms.

This happened on another one of my 75 series 8 years ago, I thought the new gearboxes may have had the problem fixed I guess not.

The hose is less than $100 second hand gearbox $2500 + do it tomorrow.

Cheers Steve.
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Follow Up By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 09:33

Sunday, Mar 25, 2007 at 09:33
Thanks for the info Steve. What year models were yours that had the problem?
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Follow Up By: Wayne (NSW) - Sunday, Mar 25, 2007 at 09:46

Sunday, Mar 25, 2007 at 09:46
Phil,

I thought it only happened on the early gearboxes with the power take off cover on the side.

Wayne
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Follow Up By: Member - Steve T (NT) - Sunday, Mar 25, 2007 at 09:57

Sunday, Mar 25, 2007 at 09:57
The first one was a 75 series about 8 years ago, the second one was a 2000 78 series last year.

The 78 and 79 series gearboxes are the same, so my advice is put that equalizer hose on tomorrow.

Learn from my mistake Steve.
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Follow Up By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 09:59

Sunday, Mar 25, 2007 at 09:59
Wayne, I though the same, thats why I was interested in what year models that Steve had. Maybe its just an age thing. I think all the 70series boxes have the PTO cover on the side - even your new Troopie!
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Follow Up By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 10:09

Sunday, Mar 25, 2007 at 10:09
Thanks again Steve, The 2000 model would have had the R151 box.
Wayne and I are hoping we're safe as the factory TDs have different transfer and gearbox. So far, mines a 2002 with 110k, and no problem.

cheers
phil
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Follow Up By: Wayne (NSW) - Sunday, Mar 25, 2007 at 10:20

Sunday, Mar 25, 2007 at 10:20
Phil,

The factory turbo gearbox is different in size and shape to the 78 normally aspirated gearbox. When I was look at the RV they had another Troopie next to it with a PTO winch on the front. I thought great a PTO winch would fit and then when I asked the salesman about fitting a PTO winch he said that the gearbox was different. A look under both vehicles and the gearboxes are different.

I will try and get a photo of the gearbox.

Wayne
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Follow Up By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 10:40

Sunday, Mar 25, 2007 at 10:40
Wayne,
My vehicle is a factory TD, same as yours. A PTO can be fitted to the factory TD - just check the posts a few weeks back on 70scool - a friend of mine has done it, but it took a lot of grief. Radiator sits lower is one of the issues.
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Follow Up By: Member - Davoe (Nullagine) - Tuesday, Mar 27, 2007 at 01:22

Tuesday, Mar 27, 2007 at 01:22
everyone will tell you to fit the hose problem solved
.......... WRONG
I had a 75 with the hose. I forget which is which but it would drain into the lower one and well gravity is a bitch it wont fill the top one. i usually avoided trouble by draining the bottom and refilling the top but once on a long trip it starte leaking from every orrafic so a drain and refill fixed thing
..... Hose did diddley squat
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Reply By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 07:59

Sunday, Mar 25, 2007 at 07:59
Like Wayne says, I wouldn't do anything yet. Just restore both to level and see what happens in 5000k or 10000k time. If there's an issue, buy one of those $50 hose setups that connect the two filler plugs.

The gearbox and transfer use the same oil - should be 75/90 or 75/85.
AnswerID: 229547

Reply By: icecold - Sunday, Mar 25, 2007 at 09:54

Sunday, Mar 25, 2007 at 09:54
Ok thanks, i have topped the gear box and will check it in couple weeks. so if i just add this hose to both box and transfer case, i shouldnt have to pull down the boxes? I took it to my mechanic and he went for a drive. he said there were no signs of wining or funny noises. i dont really want to be pulling the boxes appart if i dont need to. regards
Chris
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Follow Up By: Member - Phil G (SA) - Sunday, Mar 25, 2007 at 10:05

Sunday, Mar 25, 2007 at 10:05
Chris,
They look like this:


and you can get them off Ebay link here

or I've also seen them at the Don Kyatt parts shops.

Very simple to put on - unscrew the two filler plugs, and screw on the hose - takes 5 minutes.

Cheers
Phil
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Follow Up By: Member - Doug T (W.A) - Sunday, Mar 25, 2007 at 10:49

Sunday, Mar 25, 2007 at 10:49
Phil
you beat me on that one
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Reply By: Member - Doug T (W.A) - Sunday, Mar 25, 2007 at 10:46

Sunday, Mar 25, 2007 at 10:46
Go to Terrain Tamer or some 4x4 repairer and get the G/B Hose $65 , take out the two filler plugs and replace with the connecting hose ,It's a hose that allows the oil to circulate if that seal has leaked
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Reply By: Mikee5 (QLD) - Sunday, Mar 25, 2007 at 16:21

Sunday, Mar 25, 2007 at 16:21
I would be cautious about the above advice. This hose kit is used to allow surplus oil from the gearbox (which is higher) to drain back into the transfer (which is lower) The surplus oil gets into the gearbox through the faulty or worn seal between the transfer and gearbox via a sort of pumping effect of the mainshaft turning. What you have is low gearbox oil. How long had the vehicle stood before you checked the levels? Was it days or hours - this would give an indicator of how bad the seal is and how much oil can drain down through the seal when it is not moving. The seal may be too far gone for the hose to work which may result in gearbox damage due to lack of oil or the transfer seals may burst due to tooo much oil. I have changed this seal more than once on my old cruisers - you can buy a top quality silicone seal for extra dollars which should last longer. Fit the hose kit anyway as it is a good thing but find out what is really wrong first.
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Follow Up By: Member - Davoe (Nullagine) - Tuesday, Mar 27, 2007 at 01:26

Tuesday, Mar 27, 2007 at 01:26
you are correct from personall experience most of the advice is indeed erronous and the hose will do nothing
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Reply By: TrevorDavid- Sunday, Mar 25, 2007 at 19:49

Sunday, Mar 25, 2007 at 19:49
Chris, had you checked the levels before? could have been like it for a long time. Do the hose thing but make sure the hose is higher than your gear box filler or it will just drain into your transfer case. This should even out the pressure between them , no more problems. Worked with a old Hilux of mine, yonks ago.

Regards

TDB
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Reply By: Member - DOZER- Sunday, Mar 25, 2007 at 21:36

Sunday, Mar 25, 2007 at 21:36
Cobber, if you have a hdj79 the boxes are seperated and there is no way this can happen, even if it is a hzj79 the boxes are completely seperate....however, if you have a 1979 model, thats diofferent...the hose job is easiest and best...
Who has been playing with your gerarbox levels last...Toymota???
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Follow Up By: Member - Steve T (NT) - Monday, Mar 26, 2007 at 09:17

Monday, Mar 26, 2007 at 09:17
Are you saying that this can't happen to a 78 - 79 series no turbo box?

If you are, I afraid your wrong because I have a gearbox and transfer apart in my shed that says it does.

I have a 78 series box that leaked into the transfer leaving no oil in the box and it now needs a rebuild, the 78 - 79 series no turbo are the same.

If you are talking about the turbo gearbox then I am unsure with them.

Cheers Steve.
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Follow Up By: Member - DOZER- Monday, Mar 26, 2007 at 12:16

Monday, Mar 26, 2007 at 12:16
The 1hz 100 series, 78 series and 79 series with 1hz have thesame "prado" box which is a r150. The transfer is unboltable from the gearbox and comes off as a sealed unit....unlike the earlier 75's that had the h55 and were removed in pieces.
The turbo 79 has essentially an 80 series box, a h150, same thing with transfer, completely seperated, completely self contained, and in between the two boxes, there is a weep hole for draining if there is a leak from either....Now i am not saying you dont know what your talking about, i dont know what happened for one to fill the other....but if i were you, i would be getting a h150 from a standard 80 series in your truck asap, because they are stronger and dont do this at all....
Andrew
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Follow Up By: Member - Steve T (NT) - Monday, Mar 26, 2007 at 13:07

Monday, Mar 26, 2007 at 13:07
Hi DOZER

Ok to confirm my thinking I just spoke to my mechanic, He has every Toyota qualification in the last 15 years.

He helped me rebuild a 78 series (troopy non turbo ) gearbox and transfer last year, he also helped me pull the broken one apart.

When we rebuilt the spare box (out of a wreck )we replaced the rear main shaft with the new larger one, when we did this we also changed the seal between the box and transfer the seal that fails and creates the problem we are all talking about.

I now have the hose fitted as well, Gavin is also going to help me rebuild the now spare box and a hose will be fitted to that .

The 78 troopy and 79 ute non turbo are the same gearbox and transfer, they are different to the 100 series GXL and STD and are also different to the Prado.

How do I know this? Well I have a 78 troopy, a 100 series STD and 100 series GXLs, The GXLs and Prado are all wheel drive the STD 100 series is different as well I had a look and then confirmed this with Gavin.

So my advise still stands put the hose on.

Cheers Steve.
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Follow Up By: Member - DOZER- Monday, Mar 26, 2007 at 21:01

Monday, Mar 26, 2007 at 21:01
Steve, hope you have a better run with the new box, shaft and hose. Toyota specs show thesame box in the 100 std as the 78/9...i did hear they changed things on the new 100's....can you tell me (for my info) what is on the compliance plate of your 100 std (and gxl) under transaxle???
Andrew
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Follow Up By: Member - Davoe (Nullagine) - Tuesday, Mar 27, 2007 at 01:36

Tuesday, Mar 27, 2007 at 01:36
I am EXTREMELY doubfull. With no more than a few hunded ml in my TC from the G box it started piddling oil fom every orrafice. dont think there is a snowflakes in heck you could lose enough oil from your g box to stuff it without noticing (we all know what the tiniest amount of g box oil smells like.
Also a hose will not help 1 iota getting oil to move against gravity to the g box.
All this info is personall experience
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Follow Up By: Member - Steve T (NT) - Tuesday, Mar 27, 2007 at 19:33

Tuesday, Mar 27, 2007 at 19:33
Hi DOZER

The answers you get depend on the questions you ask.

I checked the trans axle as you asked and found the following, The 2 GXLs # is 151f AO48 then I checked the STD # 151f AO48 then the troopy # 151f AO23.

I asked Gavin yesterday are the gearbox and transfer the same in the 100 series GXL, STD, 78/79 series and the Prado, his reply was no there all different as I explained yesterday.

After your request yesterday I checked the # and you can see the results,
I then went back to Gavin and asked him what this means,His reply was this.

Given what I'd asked the answer is right they are all different, But looking into it the gearbox on its own is the same and the transfers are all different, the transfer on the GXL is different to the STD this is different to the 78/79 but they are the same.

The transfers separate from the gear box differently, the 100 series separate the same as you suggest and the 78/79 series separate the same as the 75 series and have the same seal problem.

So DOZER please accept my apologies as it seems we were both right and wrong.

Cheers Steve.

PS Davoe

The oil leaks into the transfer case and fills it up until it is forced out the breather on top, leaving no oil in the gear box.

when this happened to my truck it was on a dirt road and when he hit the black stuff it was to late.

The hose works it forces the oil back to the gear box.

Cheers Steve.
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Reply By: Member - lyndon K (SA) - Monday, Mar 26, 2007 at 08:54

Monday, Mar 26, 2007 at 08:54
ERRR does that mean because i have a 2004 T/D troopie i won't have this problem?
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AnswerID: 229752

Follow Up By: Member - DOZER- Monday, Mar 26, 2007 at 21:04

Monday, Mar 26, 2007 at 21:04
I reckon you shouldnt if it is a factory turbo...because it has a H150 as in the 80, which never had this problem, the r series boxes, in the 1hz's im not so sure about anymore....
Andrew
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