75 Series Trans case pumping oil uphill.

Submitted: Thursday, May 01, 2003 at 15:24
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Reply By: Janset - Thursday, May 01, 2003 at 15:31

Thursday, May 01, 2003 at 15:31
Ooops. I will try again, Curse that flying fickle finger :-)

My previous Troopie, the old style were famous for pumping the oil uphill from the Transfer case to the Gearbox. I am told that this was because there was only one seal between the 2 cases. So to overcome this problem, the most comon and cheapest method was to fit an interconnecting oil line between the 2 filler plugs and thus no more problem.

I have been told that the problem on the 75 series no longer exists as they (Toyota) now have 2 seals back to back which is supposed to stop this uphill pumping.

My question, does anyone out there have any knowledge in this reguard or, has anyone heard of this still happening?

AnswerID: 18902

Follow Up By: Allyn (Pilbara) - Thursday, May 01, 2003 at 16:27

Thursday, May 01, 2003 at 16:27
and is this applicable to 80 series also - thanks !
FollowupID: 11839

Reply By: Member - Peter- Thursday, May 01, 2003 at 20:23

Thursday, May 01, 2003 at 20:23
I've had two 75's and yes it does happen and in the early ones (pre1990) it was due to the one way seal between transfer and gearbox and yes fitting a tube between the filler plugs was an option. The eventual fix was to fit a seal from an automatic cruiser as they had two lips to stop the atf mixing with the 90 grade.
In post 1990 vehicles if the oil pumping occurs it is a sign of far greater problems.
toyota fitted a double lip seal and an O ring to the main input shaft on later vehicles to stop the oil transfer BUT this created another problem, the transfer gears are lubricated by the oil climbing up the gear train and seeping into shafts and bearings, but due to the O ring no oil is able to lubricate the splines on the main input gear at the top of the transfer.
In my troopy this resulted in the complete wearing away of the aforementioned splines at 120,000 k's and therefore no drive, on a vehicle that had only private outback touring!
Fortunately it eventually failed at home and not outback. The cost of a new gearbox mainshaft, new transfer input gear, bearing and gasket kits for both gearbox and transfer was considerable, never mind the labour!
To check if your vehicle has the problem, remove the pto cover from the transfer and hold the pto gear (rearmost one) with one hand and then see how much you can move the input gear (front one nearest gearbox) with the other hand, any movement is too much!
I don't think that 80's have the same problem as they have a different gearbox/transfer and the 78/79 series have a gearbox/transfer similar to 100 series.
AnswerID: 18932

Follow Up By: Allyn (Pilbara) - Saturday, May 03, 2003 at 00:17

Saturday, May 03, 2003 at 00:17
now that's a rig !

Thanks for the follow up Peter
FollowupID: 11942

Follow Up By: Old Jack - Friday, May 09, 2003 at 17:51

Friday, May 09, 2003 at 17:51
I thought they would have fixed that problem long ago in there gearbox/transferecase. I remember 1974 model tojo's doing this, a better fix was remove G/Box & T/Case, fit two thin lip seals back to back in place of the original, problem solved. sounds like toyota was a few decades to slow with the double lip seal fix!
oh well remindes me why they always show people jumping up & down in their adds on TV!
FollowupID: 12324

Reply By: Member - Topcat - Thursday, May 01, 2003 at 22:07

Thursday, May 01, 2003 at 22:07
I've got the oil transfer setup on my gearbox/transfercase (1990 model)& the transmision has done 258,000km without any problems. Change the oil every 25,000km & it is still going strong. Usually the first sign of internal troubles will be the seals on your output drive shafts will start leaking due to oil contamination wearing out the seals.Have Wheels Will Travel
AnswerID: 18945

Reply By: Bob Y. - Qld - Friday, May 02, 2003 at 06:02

Friday, May 02, 2003 at 06:02
G'day All,

Sold a 75 series last year with transfer hose fitted, and it was a late 90's vehicle. Have had 2 80 series, and work with 3 79 series, but haven't seen this problem so far.

Re Peter's gear problem, towed an opal miner's 75 tojo, out of a creek, where the gear had finally worn out the splines. Was wet as buggery too, but lucky? for them they were in hard country, to work on it. The other cause of this is the large nut on end of main shaft becoming loose. The qiuck fix is to weld the 2 rear gears together, in situ, or buy a made up gear that advertised in 4WD mags.

Good idea about the regular oil changes too. hooroo...

AnswerID: 18949

Reply By: Janset - Friday, May 02, 2003 at 11:45

Friday, May 02, 2003 at 11:45
Thanks guys.

More information the better. I think as a safe guard a bypass hose connection is in order, and of cause the regular and mandatory oil changes.

AnswerID: 18964

Reply By: Member - Peter- Saturday, May 03, 2003 at 06:55

Saturday, May 03, 2003 at 06:55
Something I should have mentioned before about the gearbox and transfer parts. Toyota wanted heaps for the mainshaft and input gear and I was able to get them, a gasket kit and bearing kit from Don Kyatt at Seven Hills, parts looked identical (except for the worn bits ;-)) and cost about a 3rd of genuine. I would get a genuine gasket kit though as the Kyatt gaskets leaked despite putting sealer on them as well.
AnswerID: 19032

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