FJ40 why do I have a hose from transmission to transfer case (see picture)

[Wadesters]

I have a 1980 FJ40. I removed the skid plate to adjust emergency brake. I noticed there is a rubber line going from the 4-speed transmission fill to the transfer case fill. I have not see this before and just wondering if anyone knows the purpose. It does have a Dakota Digital dash installed. Is that why the line has been installed? First Dakota Digital setup I have seen.

Thanks..

 

[wngrog]

Because the seal between the two has failed. This allows the fluid pumped out of the transmission into the tcase to return to the trans.

 

[Living in the Past]

This trick has been around a long time. I know Man-A-Fre sold a kit that included fittings, clamps and hose. Probably still sold as a kit by a vendor or two.

 

[onemanarmy]

^Yes. There was/is a guy on here recently that made some for sale.

Its a band aid. Still keep an eye on fluid levels.

 

[Wadesters]

Not sure I understand? A band aid how? In case one fluid source runs low?

 

[wngrog]

Not sure I understand? A band aid how? In case one fluid source runs low?

It works but does not keep either at optimum levels.

 

[thebigredrocker]

The hose doesn't necessarily mean the seal has failed. Some people add the bypass for peace of mind.

Tranny to Transfer case bypass hose

I've had a couple of request to give more detail on this setup. The hose is a steel braided -08 Parker "Tough Cover". The centerline distance between the fittings is 15" to 15.25". I made two, and they both fit. The short one is currently in place. The fittings are 37 Deg Flared Compression...

forum.ih8mud.com

 

[pb4ugo]

Not sure I understand? A band aid how? In case one fluid source runs low?

When the seal between the T/case and trans go bad, the T/case will pump its oil into the tranny and the t/case will run dry. This band aid allows the excess oil in the tranny to run back down to the t/case so it wont be starved for oil. Your set up, to me, looks iffy, because of the height of the tranny hose in relation to the actual height of the fill port. By the time the trannys oil gets to the level to flow down to the t/case, the t/case maybe empty. Unless the oil levels are overfilled.

 

[Wadesters]

Seems to me with all the comments I should remove the hose and go back with single plugs the way it was designed.

 

[brian]

Unless the seal between the trans and transfer has failed...which requires splitting the two in order to be replaced.

 

[Wadesters]

After more searching I found this thread: Transmission/Tcase equalizing hose

Seems a lot of people like the connecting hose.

 

[1Fine40]

I think of it as an insurance policy now...I installed one when I put in my Orion T-Case. I just fill both boxes per normal
and check on the fluid levels at each oil change...so far, it seems to be doing its job. Prior to the Orion, I had a
3 speed case that ran pretty well dry before I got the word that the transmission was overflowing ..(Nice noisy rumbling sound coming from the tcase..) Sort of precipitated the move to the Orion... win/win I guess! YMMV...

 

[GLSisk]

I know I'm late to the party, but I've been running this setup for close to 20 years and love it. I agree that it's important to make sure the oil levels are correct, but as with many, it only took one time of me taking the transmission plug out and having oil shoot out to make me a believer. It's simple, easy and works great when setup correctly....

 

[JohnnyC]

I've been running this setup for close to 20 years and love it.

X2 mine has been on for 20 or so as well

Think I got it from MAF