3-speed Oil Diverter -What witchcraft is this?

[Pans4evr]

Learn me please……

I was changing all fluids today on a new to me 1970 FJ40. I know nothing about any past work done on it. To my surprise, no fill plug on the 3Speed transmission. The casting boss and threads there, but no plug.

Alas, there is a diverter line running from the top of the tranny to the xcase.

Are both cases filled via the plug in the xcase, or alternate method for filling both?

My did search here and elsewhere for “Diverter line”, with no success. So please help me understand the maintenance steps here.

Thanks in advance… pics below

 

[pjohnson]

A common fix-it for when the seal between trans and tcase fails is to attach one of these hoses to redirect the overfull side back to the other. I can never remember which direction the fluid goes.

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FJ40, FJ45 and FJ55 Transfercase, Gears, Gaskets and Seals 1963-8/80 Land Cruiser - Specter Off-Road

Toyota Land Cruiser parts since 1983. From the oldest FJ25 and to the newest Land Cruiser, Non USA or domestic 40 Series, 60 Series 80 Series or 100 Series, SOR has the largest selection of top quality new and used OEM and aftermarket Land Cruiser parts in stock in the world. Specializing in...

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[pjohnson]

Btw, the bolt on the side of the transmission ( driver side) is the fill plug.

Correction, driver side. I mis-read SOR's diagram.

 

[Living in the Past]

That is where the manual shift for the transfer case pivots off of. Like mentioned fill is on the driver's side of the transmission.

 

[Pans4evr]

Pjohnson, So that I understand, I must remove the Diverter line on the Yranny side to fill Tranny. Makes sense, just confirming.
Thanks for your help…

 

[pjohnson]

Yes, I believe that is how these systems work. I don't know this from experience though, never had one.

 

[70fj40]

As stated above that line is called a bypass hose. When the seal is bad between transfer case and transmission the oil can be pumped out of the transfer and into the transmission. The fill plug for transmission is higher than the tcase fill plug and so when the fluid overflows in the transmission it migrates thru the bypass hose back to the tcase. Best to check level in both and fill both to where it runs out of fill plug in each.

 

[70fj40]

The correct solution is to separate the tcase from the tranny and rebuild/reseal it then replace the seal between the two and reinstall