Transfer case severe leak

After driving my truck on a 300 mile round trip last night , I woke up to a puddle of oil in my garage (about 1/8 cup total so it wasn't a minor leak). I got under it tonight to find I have a transfer case leak. As you can see the leak is actually bad enough to drip (you can see one is about to fall when I took the picture).

I cleaned off as much oil as I could in hopes of finding the source of the leak but in the 6 hours since it has not shown any signs of leaking. I plan on brining it in to a local transmission shop for a look but am afraid to drive it after such a significant leak.

Since I don't know how much oil was lost during the trip, would you drain/replace the transfer case oil before driving it in (about 11 miles) to ensure it has ample oil for the short trip?

If so, I assume it is simply remove fill plug, remove drain plug, drain, return the drain plug, add the oil to the fill plug opening, torque down both plugs (not sure how much torque they call for)

Sorry for the basic questions but I am a noob when it comes to any type of wrenching. The most in depth things I have done are simple things like switching LEDs in dash, cleaning MAF and Throttle Body, Headlights etc.

 

Hey Double Deuce,

Were you the one the Stones were writing about in their song Tumbling Dice? I sure hope you are getting some royalties. Just like they said you have to Roll It. LOL.

Okay, so now let's get to the transfer case issue. It is very wise for you to be concerned about the transfer case since both the rear and front drive shafts are completely controlled by the transfer case. The transfer cases on first generation Tacomas are chain driven. If they are not properly lubricated, they will break, and you will be searching for a new or used transfer case. You have the method down on how to drain and fill the transfer case. I don't know what the torque specifications are for the bolts, but if you are just driving it a short distance to a shop, then, you are probably okay just to snug up the bolts. Don't drive it at all if there isn't any lubricant in the transfer case.

Good Luck,
Paul

 

Hmm, sounds to me like the seal is bad. There is an extension housing on the transmission where it mates with the transfer case- there's no oil in that assembly, which is why that connection isn't RTV'ed. The transmission has an extension shaft coming out the back that splines into the input of the transfer case, both ends of the shaft have oil seals. When either leaks it fills up the cavity between the tcase and transmission with oil.

Pain in the ass to fix, basically have to pull the tcase and after replacing the seal carefully reinstall it, almost easier to pull the whole transmission and do it off the truck because it can be difficult to get them mated back up without crushing the new seal.

If the transmission is off you can set it upright with the bell housing on the floor and then easily drop the tcase on without crushing the seal. Makes sure to grease the seal before they're mated up.

 

If your immediate concern is about driving it with a low level of oil, you could just remove the fill plug, and top it up with 75-90w gear oil. When adding or filling, you are supposed to add oil until it just starts running out of the fill hole.

 

Check to make sure the breather isn't clogged. Also, pull the shifter boot to make sure it's not coming from there.

 

Thanks for the advice Cooper4x4. Haven't had a chance to do that yet but I can state that the transfer case is full. I pulled the fill plug and it was still full (to the fill plug level).

 

If it is in fact a leak from one of the two seals and it's leaking in the void between the tcase and transmission, be sure to check the fluid level of the transmission too, if it's a manual (if it's an automatic it'd be atf not gear oil). If you run that too low you can obviously do damage, this happened to me and I cooked the front input shaft bearing and had to replace the whole transmission.

 

After cleaning everything up, and checking the transfer case it was obvious it was not leaking from the transfer case itself. It appears to be venting pretty bad. I brought it into a local transmission shop and they are recommending a transmission cooler which I already planned on adding anyway but nothing more at this point.

My question is for it to be venting this badly on relatively flat ground and highway driving, is it likely that there is an issue with the torque converter causing it to heat up? Again we are buying a small camper shortly and will be towing with it. (around 2500-2800 lbs)

 

Turns out it was venting and was also leaking around the Transfer Case Position Switch.
Drained and replaced (did not flush) the ATF, added a Tru-Cool Tranny Cooler, and replaced the transfer case switch. Hopefully it is smooth sailing from here.

 

I had a similar issue that turned out to be the transfer case was over full...drained the excess and no more problem!!