Assistance with Transfer case oil cooler Mod

First off, my truck is not a DD, purely a play truck.
its a 1998 toyota tacoma ext cab 4wd long travel front and rear.

i drive my truck hard in the dunes in 4Lo for long periods of time, at high speeds, bouncing off the rev limiter often.
my transfer case gets HOT. i know it because i can smell it burning oil.

i know its bad, i dont care, i just want to try and make it last.

so heres my thoughts, the manual transfer case doesnt have any lines coming out of it, so i want to drill and tap a fitting into the bottom, drill and tap a fitting into the top, (right above the Low gear, the gear that makes 4 Lo work is on the top right? and thats what is so getting hot right?) then put an oil cooler in my bed, with a external pump, so it will consistantly pump oil through and dump it onto the low gear..

give me your thoughts.

 

Just wondering why you drive it so hard in4Lo in the dunes?

 

because even though im geared to 4.88s i just dont have enough power in the big dunes to even stay in 2nd gear. and im a 4 banger.
i know its hard on the truck, gotta pay to play!

and if you dont have momentum and power, you are going to get stuck lol

 

Before I went to all that trouble, I would first want to know just how hot the gear oil is. So I would find, or have made, an adapter to fit a temperature sender into the drain plug of the transfer case, run the wiring to the cab/gauge, and see how warm things get when I was beating on the truck. Based on that, then you'd know more about the conditions inside the transfer case. I'd also have a sample of oil from the transfer case sent out for analysis of contaminants, viscosity, TBN/TAN and flashpoint.


If that told me I was actually running the truck too hard for the oil to keep up in the transfer case, then I would stop and rethink the plan. First off the 1st gen transfer case has an internal pump (it's not splash lubricated). I would see if I could adapter a line from that, to an external cooler, and then route it back in via either the fill hole or through one of the other openings in the case. If that was a no-go (pump probably won't have the ability to lift and push the oil that far), then I would consider your idea.


But, I would not bother to run it to the bed. I would put it up front, ahead of the A/C condenser, as if it was a cooler for an A/T. Air flow should be better, and I think your routing options would be more reasonable. I don't have a 1st gen any more so get under there and have a look to be 100% certain, but I think I would route the return line to the top of the transfer case and tap the breather for my return line. For the send line, I think you'll have to drill and have a bung welded in. You could drill and tap, but I don't like tapping aluminum if I don't have to.


It's an interesting idea. Maybe not a good one, but certainly interesting.

 

thanks so much for your help!!

are you sure a manual tcase for a 98 tacoma isnt splash lubricated?
this is the kind of information i need!

 

I don't think that would work, pretty sure its like a differential and is splash lubricated, don't know how you'd get the right oil level with a bigass line going to the front of the truck... Did you think about just getting synthetic fluid with some kind of friction inhibitor additive?

 

Not sure what your final setup will be, but I have a brand new engine oil cooler, (or cooler for fluids thicker than atf), some hoses, headed for the for sale section. If you picked up a dry sump oil pump the setup would easily work. I doubt location would be that critical, since any cooler will expell heat with minimal flow.

This guy has a used electric oil pump.

http://www.tacomaworld.com/forum/buy-sell-trade/294350-random-parts-sale.html

For short money you could easily make this happen.

FWIW, my truck also runs added coolers, not like yours but I run a large ATF cooler for the trans. Removing the trans fluid passing thru the radiator and smaller oem cooler. I took the smaller cooler and replumbed it for a power steering cooler.

I also run remote filters on the ATF and powersteering fluid.

PK

 

No, it's not splash lubricated.

http://www.toyotapartsoverstock.com/showAssembly.aspx?ukey_assembly=489712

It's not much of a pump, but it does have one to circulate the fluid. I question if it would be enough to push fluid all the way through a cooling circuit.

 

How do you know its your transfer case getting hot?
What about your diffs & transmission?

 

thanks for the information everyone!
on to the research i go.

my diffs get hot, but not that hot, i can tell when i change the oil. the diffs are meant to be put up to that kind of abuse.
the tranny oil is always clean, and its a manual tranny so they dont get hot too often.
my transfer case oil is FILTHY, horrible, smells like.....yeah. and they arent meant to be ran in 4LO for long periods of times at higher speeds... so thats how i came to that conclusion.

 

So, why do you run in 4lo - in the dunes?
Save your transfer case and use 4Hi..... I'm pretty sure you can get the same results in 4hi if you change your driving habits from what you're used to.

Are you using synthetic ATF?

 

because i dont have enough power even with 4.88 gears. i cant even stay in 2nd gear in 4hi.
yeah if i want to stay in first gear i can... which im not doing. my first few posts explain.

im not..... i should change that..