Transmission/xFer Case Fluid Cross-flow

[JohnL]

Transmission/xFer Case Fluid Cross-flow (On Purpose!)

I've heard and read that some people have linked their x-fer case and transmission via fittings and hose. Some have commented on this as a solution to fluid migrating from one to the other, leaving one full and the other empty.

What's the correct connection order to do this? If anyone knows the plug size and thread pitch off the top of their head, they'll save me a trip home first!

Is it
1. transmission drain-to-xfer fill?
2. x-fer drain-to-transmission fill?
3. Drain-to-drain?
4. Fill-to-fill?

Does it matter?

I don't think this is rocket science (or hydraulic engineering?), but would prefer to benefit from someone's experience (isn't that what this is all about?!?!)

Thanks all,
John

 

[Cruiserdrew]

It matters a lot and the correct answer is fill to fill. Typically, the transfer case will pump the oil up hill, into the transmission. So when it gets to full (above the fill plug) you want it to run downhill and fill the transfer case. This is a seriously common problem in my limited experience. My 40 did this untill the SM420 went in, and my 60 does it as well. My friend's FJ40 did it, but just got an Orion so that hopefully cured it. I think it's a Toyota design feature, but I don't know what the purpose is.

 

[Jan-78FJ40]

IMHO it's a failure of the seals between xmission and xfer. in the manual trucks it is easily cured by the fill to fill connection.
The same happened on my FJ62, and since that one runs ATF in the transmission, the only cure is to pull the transfer and fix the seal in between.

 

[Bennett]

I think alot of trannys to t-case fail at the seal because of poor installation. I was guilty of that myself. Even with help it is easy to bugger up teh seal as you lift on the t-case and position it back on over the splined shaft.
My solution was to get 2 long bolts that fit the back of the tranny and cut off the heads. Screw them into the trans into the upper left and right hole.
Pick up the t-case and position it onto the 6" long bolts and gently slide it into place. Put in lower bolts and remove the long bolts.
I cut a slot in the guide bo;ts to be able to remove them with a flat blade screwdriver.
I'm sure this has been done by others but it might help someone .

As I recall teh correct position of the seal is "spring side towar the t-case"

CAN anyone confirm that?


Bennett

 

[Mick]

What parts are needed to conect the transfer box to the main gear box ? I think I understand the principle but don't know how to go about it.

Thanks

Mick

 

[HI^C]

SEALED Bearing

 

[Robert LaDuke]

In my opinion the best solution is to replace the seal between the T & T.
Here's a pic of the device that MAF sells. Looks like you could build this yourself if you wanted to.
http://www.man-a-fre.com/parts_accessories/oilreturnkittransmissiontransfercase.htm

 

[Paul_A]

As I recall teh correct position of the seal is "spring side towar the t-case"

CAN anyone confirm that?


Yes, that's correct.

 

[Mick]

Thanks for the link Robert. I have just orderd a seal and gasket to fix the problem, but the trouble is that I don't want to find out that it's leaking again when it's too late. I think I got away with it this time, ( least everything seems to be working OK) so I was thinking of installing a tube linkage as well. I notice that the oil return kit is "transmission to transfer" but my problem has been with oil leaking from the transmission int the transfer box, I need to get it back to the transfer, not the other way around, does it work both ways ?

Thanks

Mick

 

[JohnL]

If you go fill-to-fill, yes, it will go both ways (insert David Bowie joke here)

 

[IDave]

Definitely AC/DC, iffn' you go fill-to-fill.

 

[tobydog]

I did this on my 40 works great. Manafres price is pretty good it cost me over $70 buying parts at hyd. shop. Still cheap insurance.

 

[Landpimp]

yep, I used MAF kit, $50, worth it for not having to look for or make some crap up. Now it turned out I really didnt have a problem but I left it on for good measure.

 

[Robert LaDuke]

Thanks for the link Robert. I have just orderd a seal and gasket to fix the problem, but the trouble is that I don't want to find out that it's leaking again when it's too late. I think I got away with it this time, ( least everything seems to be working OK) so I was thinking of installing a tube linkage as well. I notice that the oil return kit is "transmission to transfer" but my problem has been with oil leaking from the transmission int the transfer box, I need to get it back to the transfer, not the other way around, does it work both ways ?

Thanks

Mick

Mick,
I like your idea of installing the tube as insurance. I think i may do the same. My seal seems to be holding so far but i don't want to find out the hard way that it failed.
Bob

 

[Bennett]

Wondering here...

If you use the tube.... what if the t-case pushes oil faster than the tranny can push it to the t-case?
Which from what I have read is highly possible... Dry t-case??

nuther problem?

 

[cruiser_guy]

I did this on my 40 works great. Manafres price is pretty good it cost me over $70 buying parts at hyd. shop. Still cheap insurance.

Ya got hosed!!! My hydraulic supplier charged me about $25 less the hose.

 

[wesintl]

Mick,
I like your idea of installing the tube as insurance. I think i may do the same. My seal seems to be holding so far but i don't want to find out the hard way that it failed.
Bob

Yeah.. I found out the hard way.. new trans and case later :whoops:

Really, I don't know how it can be prevented other than changing the seal regularly (meaning every 60k or 100k...

Both my cruisers have the MAF kit now as ins..,

 

[Mick]

Who is your supplier cruiser guy ?


Robert. Yes as an insurance. I think I got away with it lightly this time, but I would not like to chance it again.

Bennet I think it's just flows from one case to the other when the levell rises in one rises above the other.

Mick

 

[Mick]

Yeah.. I found out the hard way.. new trans and case later :whoops:

Really, I don't know how it can be prevented other than changing the seal regularly (meaning every 60k or 100k...

Both my cruisers have the MAF kit now as ins..,

Did your transmission seize or did it give up on you a while later ?

 

[burnt03]

Maybe I missed it somewhere above, but does anyone have the specs for the hydraulic fittings? Do they make them big enough to just screw into the fill plugs spot or do you have to drill and tap new holes for the fittings?