Tranny to Transfer case bypass hose (1 Viewer)

[PabloCruise]

Which way does the oil tend to go if seal is bad TC or tranny ?

In a Landcruiser it always pumps from the transfer to the tranny. In a Jeep it is normally the other way around. It pumps from the unit that has the higher pressure to the unit with the lower pressure. The hose helps reduce the pressure differential and lets the excess pumped into the tranny drain back to the transfer case.

I believe when the seal is failing, it pumps to the tranny, and once the seal has fully failed it goes tranny to t-case...

Moral of the story: check fluid in both

 

[tlc4x]

I have one of these hoses for my old 4 speed I took out. It sounds like it would be advisable to put it in my 5 speed just in case.

 

[Teebag]

Yeah, would you guys continue to run with it anyways even after fixing the seal?

 

[MoCoNative]

I have a question, I have a leaking seal between the two, actually started leaking within 10,000 miles of replacement. But I have a PTO, toyota stock unit fitted to the transfer. So the hose will not run right. It is mentioned above that part of the issue is pressure. Will a hose between the two help at all? It probably won't allow the fluid to gravity feed back to the transfer, but would it equalize the pressure such that the transfer of fluid would be reduced.

Any insight on this, anyone?

 

[ducktapeguy]

I'm planning on leaving it on even after I fix the seal because there's no reason to take it off. I see no disadvantages to having the hose connected, it can only help if the seal does fail again.

I was also curious to know whether a pressure difference was the root cause behind the fluid transfer, so I felt around the transfercase vent and I didn't see a problem. So I suspect there must be another reason for the oil moving upward. I started to remove the tranny cover to get a better access at the vent, but ran out of time and had to button it all back up to drive it. Next time I take off the cover, I'm going to disassemble the vent and add a breather hose, so I'll know for sure if the vent is plugged. But my guess right now is that pressure differential is not the primary cause of the problem. Other than that bit of info, I can't really help you.

 

[inkpot]

I made my first one of these about 30 years ago for my 72 FJ-40. I went lo-tech. I drilled out the two inspection plugs and tapped a thread in them to fit a brass hose barb. Connect the barbs with 5/16 fuel line. Lasted for years. Never leaked. As long as the breather on the transfer is working, there is no pressure in this line, just gravity feed gear oil trickling from the transmission down to the transfer. Cost was under $10, and I did it with a hand drill, hand tap, and a bench vice. Only drawback to leaving it on permanently is just a minor nusiance value when checking fluid levels. John

 

[Teebag]

Ta Ink, that is how mine is at the moment.

 

[island45]

My seal have been shot because it always ran into the transfer. In that case the bypass hose didnt help at all. So I did the hose barb fittings and plumbed in a pump off of a 90 wt pump bottle, sorta like the ones for hand soap. It had a clear vinyl tube going back up to the tranny. Just every now and then, I would climb under and pump untill no more gear lube was moving through the line....I saw a picture of it on Landpimps gallery, so I'm thinking it must still be functional. Not a setup for serious off-road work, but it looked way easier than pulling everything apart.

 

[Blue77FJ40]

Bsevens, do you know if there is a fitting that fits directly into the fill holes without adapters? I have the MAF version, and to view/check the level of gear oil, I have to remove the adapter. This would also avoid using two wrenches.

Thanks, Dan

 

[inkpot]

Bsevens, do you know if there is a fitting that fits directly into the fill holes without adapters? I have the MAF version, and to view/check the level of gear oil, I have to remove the adapter. This would also avoid using two wrenches.

Thanks, Dan

Howdy! Don't know if you could change the MAF setup, but on my setup, I have to loosen a hoseclamp with a screwdriver, then it takes a flairnut, or open end wrench to remove the OEM plug. If the gearboxes are venting the way they ware supposed to there is not much pressure in either of them. If you don't see obvious leakeage, you should not have to check the fluid level very often. John

 

[KY Longhunter]

Is this where bypass hose would go if I purchased one?

see yellow line in picture.

 

[Fuzzy Logic]

Correct

 

[Blue77FJ40]

Howdy! Don't know if you could change the MAF setup, but on my setup, I have to loosen a hoseclamp with a screwdriver, then it takes a flairnut, or open end wrench to remove the OEM plug. If the gearboxes are venting the way they ware supposed to there is not much pressure in either of them. If you don't see obvious leakeage, you should not have to check the fluid level very often. John

I have plenty of obvious leakeage. Enough to check it after each trip.
A rebuild is planned at some point.

Bump for Bsevans on whether the adapter can be avoided, thanks.

 

[twoturtlesracing]

I've had a couple of request to give more detail on this setup. The hose is a steel braided -08 Parker "Tough Cover".

Where should I look for this? I'm not to familiar with having hoses made so be patient with my ignorance!

The fittings are 37 Deg Flared Compression.

Will a good shop have these in stock?

Thanks!

 

[inkpot]

Where should I look for this? I'm not to familiar with having hoses made so be patient with my ignorance!



Will a good shop have these in stock?

Thanks!

You can make this as fancy and expensive as you want, but it is not a pressure critical setup. If either of the gear boxes are properly vented, then there is NO pressure it it at all. It takes $10 and 1 hour to do the whole thing. Any hardware or automotive parts place should have everything you need. This is not a NASA project. John

 

[fjwagon]

I have this problem with my 79. I will take it down when I install the orion. I don't daily drive it but If I did it really does not matter, regardless, it's good insurance.

 

[Pin_Head]

I realize it's a $6 seal and a little more work than most are willing or able, but why not just fix the problem?

It isn't the seal on 4 speed cases, it is the worn splines on the output shaft and the gear oil seeps through the splines. Replacing the seal won't change the situation. I think it was Mark Algazy that figured this out, but I wish it was me.

 

[backcountry1]

But I have a PTO, toyota stock unit fitted to the transfer. So the hose will not run right. It is mentioned above that part of the issue is pressure. Will a hose between the two help at all? It probably won't allow the fluid to gravity feed back to the transfer, but would it equalize the pressure such that the transfer of fluid would be reduced.

Any insight on this, anyone?

I am currious about this too? I have PTO as well,

I would need a longer hose, and it would not run as straight between the too holes.
would this work or would the dip in the render the hose useless?

 

[rusty_tlc]

There is a very inexpensive and customizable solution to this problem.
My FJ60 has the issue, my solution was to drill and tap two fill plugs for a 1/8" NPT fitting, then I used a couple of hose barbs and a piece of oil resistant hose I got from the local hose and fitting store secured with a couple of SS hose clamps. I doubt I have $10 invested in it.

 

[inkpot]

I am currious about this too? I have PTO as well,

I would need a longer hose, and it would not run as straight between the too holes.
would this work or would the dip in the render the hose useless?

This is a gravity feed solution. If the highest point on the bypass hose is lower than the fill/check hole in the transmission case, then it should allow the fluid to flow down to the transfer case. It is cheap enough, and simple enough, to test the theory. With a longer hose run, I would recommend using the largest hose size that is practical, to allow the fluid to flow. John