Transfer case leaking!

[hertahoe]

I (wife) have a 2005 Tahoe LT with 135k. I noticed a drip on the driveway after I changed out the water pump over the summer. Thought something went sideways with install, but it turned out to be farther back. Drip wasn't bad and so I ignored it. 2 weeks ago I changed out the transfer case motor. Was underneath the Tahoe, I noticed a substantial amount of fluid on case, undercarriage and crossmember. Tried to find leak and thought it might be coming from gasket. So I researched and it turns out they have a pretty well known issue caused from pump and creating a whole in case. This is what I think I may have. Other than taking it to shop for diagnosis. What can I do to find the leak? I will check and fill with the fluid I ordered in meantime. If I have to, I don't mind buying a new case and doing the removal and install. Videos I watched, the guy took the transfer case to shop for partial rebuild. Just thinking out loud.

 

[Tonyrodz]

You could always power wash underneath, get it as clean as possible, park it and slide a large piece of cardboard under the general area of the drips. Let it sit overnight then check it in the morning.

 

[George B]

Take a can or two of brake clean and wash the back half of the case. They don’t leak when sitting still so you need a good solid highway run. Then take a look for a wet spot on near the base of the tail housing. Check all around because there are four possible leak points. Once you find it you can make your plan. I made a temporary epoxy fix on mine until I swapped the housing. Not a hard job really.

 

[Doubeleive]

ya the case rub is very common, there is a thing they fix it with called a "case saver" but that requires basically rebuilding it. sometimes a rebuilder will use a better case that won't rub but that cost more.
you might get lucky finding one in the junkyard that has already been rebuilt or is clearly not leaking, typically I think rebuilds are around $1200 but that was several years ago and now we have some inflation so....
I know there is a lot of them on ebay, both used and rebuilt, they are generally pretty tough, aside from developing leaks so if a clean used one is around that may save you some money
whatever you decide it will need to be replaced with the exact same model, you will see a silver dollar sized plate attached to the side with some numbers stamped or printed on it, that's what you need to match up.
small chance it could just be the output seal but like stated above you will want to clean it up and keep an eye on it, purple power works really well for cleaning, you can find it at wallyworld and autoparts stores.
and if you just make sure it has fluid in it and it's not leaking like a faucet you can just drive it with a leak forever basically until it just leaks too bad.

 

[YukonRog]

If you read some more on the pump rub issue, or watch some videos, they will provide you with instructions of exactly where to look for the break through in the case. As mentioned, if you clean the area well you can make a temporary patch with some JB Weld or other product like it. I recently rebuilt my wife's Transfer Case in her '05 Yukon. It was a NP 246 model which is the most common and probably what you have in yours. Parts for the rebuild were around $100 and easy enough to do if you watch enough videos. You do however need a hydraulic press in order to remove and replace about 5 bearings. I bought an inexpensive one from Harbor Freight. The hardest part of the entire job was removing and replacing it. It has to be tipped and turned and it weighs around 65 lbs. Whatever you do, don't allow it to run dry. You can remove the Transfer Case and just replace the rear case but if it's out I recommend a full rebuild.

 

[swathdiver]

I (wife) have a 2005 Tahoe LT with 135k. I noticed a drip on the driveway after I changed out the water pump over the summer. Thought something went sideways with install, but it turned out to be farther back. Drip wasn't bad and so I ignored it. 2 weeks ago I changed out the transfer case motor. Was underneath the Tahoe, I noticed a substantial amount of fluid on case, undercarriage and crossmember. Tried to find leak and thought it might be coming from gasket. So I researched and it turns out they have a pretty well known issue caused from pump and creating a whole in case. This is what I think I may have. Other than taking it to shop for diagnosis. What can I do to find the leak? I will check and fill with the fluid I ordered in meantime. If I have to, I don't mind buying a new case and doing the removal and install. Videos I watched, the guy took the transfer case to shop for partial rebuild. Just thinking out loud.

View attachment 355804

Required watching:

At about the seven minute mark Richard points to where they usually wear through the case, under the front output shaft. If my teenage daughters can do it, you can too.

 

[George B]

For the record. My case had 230k on it and was working fine other than the pump rub. I just swapped the case half and kept on going. A rebuild may not be necessary. It took me three hours.

 

[Fless]

If you read some more on the pump rub issue, or watch some videos, they will provide you with instructions of exactly where to look for the break through in the case. As mentioned, if you clean the area well you can make a temporary patch with some JB Weld or other product like it. I recently rebuilt my wife's Transfer Case in her '05 Yukon. It was a NP 246 model which is the most common and probably what you have in yours. Parts for the rebuild were around $100 and easy enough to do if you watch enough videos. You do however need a hydraulic press in order to remove and replace about 5 bearings. I bought an inexpensive one from Harbor Freight. The hardest part of the entire job was removing and replacing it. It has to be tipped and turned and it weighs around 65 lbs. Whatever you do, don't allow it to run dry. You can remove the Transfer Case and just replace the rear case but if it's out I recommend a full rebuild.

The NP246 weighs north of 80 lbs dry...

 

[YukonRog]

The NP246 weighs north of 80 lbs dry...

Dang! I'm stronger than I thought! And I changed the back case to the upgraded hardened one which was I think 5lbs heavier. I beasted that sucker up there by myself lying on my back and the vehicle wasn't high enough to lock my elbows out. I guess all those years of pumping iron paid off! I know I'm weaker now at 68 with all my maladies too. But hey when I was younger I could tear a 2" phone book in half!

 

[hertahoe]

You could always power wash underneath, get it as clean as possible, park it and slide a large piece of cardboard under the general area of the drips. Let it sit overnight then check it in the morning.

Take a can or two of brake clean and wash the back half of the case. They don’t leak when sitting still so you need a good solid highway run. Then take a look for a wet spot on near the base of the tail housing. Check all around because there are four possible leak points. Once you find it you can make your plan. I made a temporary epoxy fix on mine until I swapped the housing. Not a hard job really.

Can't believe I didn't think of brake clean...Thanks.

 

[YukonRog]

I've found Zep products to be great for degreasing. Orange Concentrate and Green Heavy Duty. I found Home Depot sells them but I started using their products in Industrial Applications. I had a Oil Sender blow and it coated the entire under carriage with oil. I sprayed it on concentrated, waited a few minutes and then pressure washed it right off.

 

[George B]

I've found Zep products to be great for degreasing. Orange Concentrate and Green Heavy Duty. I found Home Depot sells them but I started using their products in Industrial Applications. I had a Oil Sender blow and it coated the entire under carriage with oil. I sprayed it on concentrated, waited a few minutes and then pressure washed it right off.

Have you ever used this stuff. Holy Smokes!

Amazon.com: North Woods Fire Ball - Foaming Citrus Solvent Degreaser (Pack of 24) : Health & Household

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www.amazon.com

 

[YukonRog]

Sorry not Green. Zep Purple. I got confused.

 

[hertahoe]

Finally got around to looking at this more and have watched many videos on the transfer case. Used brake clean to degrease the underside of case and the area by output seal. Changed output seal since the tail was pretty gooped up. The top of case has no wet areas, only the bottom of the case, mostly by the 246 badge. I would imagine after watching some videos I would be able to pinpoint where it's leaking, but I don't see any visible leaks, cracks or pinholes. I had my wife change from reverse to drive while idling and I was under to see if it would create the leak point. NOPE! Nothing leaking from seal on bottom or case or bolts. Very strange. I am going on a trip that is close to 300 miles each way this wknd! I'm bringing extra fluid just in case.

 

[George B]

Finally got around to looking at this more and have watched many videos on the transfer case. Used brake clean to degrease the underside of case and the area by output seal. Changed output seal since the tail was pretty gooped up. The top of case has no wet areas, only the bottom of the case, mostly by the 246 badge. I would imagine after watching some videos I would be able to pinpoint where it's leaking, but I don't see any visible leaks, cracks or pinholes. I had my wife change from reverse to drive while idling and I was under to see if it would create the leak point. NOPE! Nothing leaking from seal on bottom or case or bolts. Very strange. I am going on a trip that is close to 300 miles each way this wknd! I'm bringing extra fluid just in case.

Wash it down and drive it a bit. then take another look.

 

[hertahoe]

Drove it again and there was a few drops of fluid. Still can't locate the damn leak! The 246 badge is held on by small screw. Could that be a potential spot for a leak?

 

[rockola1971]

The red dots are where you will typically see the small rub through holes created by Tcase pump wearing through the case.

OP I am concerned with the area circled in yellow. It appears you might have a hole. Id wire brush the circled in yellow area and look real close. Seems to be alot of grime sticking to the case in that area.

 

[ncalvo]

I had my trans rebuilt within the last 5k miles and my mechanic that did it changed the fluid in my transfer case and mentioned the drain plug being too tight he had to drill it out, and if tightened too much would split the case.
I have noticed some drips forming but in a different location. I am a noob in regards to looking at this transfer case but a quick learner.
Can anyone take a look at these pics maybe point me in the right direction or what to investigate. Seems pump rub and a hole forming is common but not what I am seeing on mine.
The rear is dry but the front has obvious drips. The drips are not bad enough to leave any fluid on the ground, I just spend a lot of time looking at every inch of my truck and noticed this.
Thanks in advance

 

[rockola1971]

I had my trans rebuilt within the last 5k miles and my mechanic that did it changed the fluid in my transfer case and mentioned the drain plug being too tight he had to drill it out, and if tightened too much would split the case.
I have noticed some drips forming but in a different location. I am a noob in regards to looking at this transfer case but a quick learner.
Can anyone take a look at these pics maybe point me in the right direction or what to investigate. Seems pump rub and a hole forming is common but not what I am seeing on mine.
The rear is dry but the front has obvious drips. The drips are not bad enough to leave any fluid on the ground, I just spend a lot of time looking at every inch of my truck and noticed this.
Thanks in advance

Your case looks like it is wet at the rear and I suspect pump rub through. I would wipe down and inspect real close in the area circled in blue and even the opposite side of the case as well. Your leak is significant and I would also check fluid level of case and top off as needed.

 

[ncalvo]

Your case looks like it is wet at the rear and I suspect pump rub through. I would wipe down and inspect real close in the area circled in blue and even the opposite side of the case as well. Your leak is significant and I would also check fluid level of case and top off as needed.

Thanks for the input, the rear of my transfer case is bone dry, I see no fluid near the rear bolts or anywhere further to the rear. The picture does make the rear case bolts glossy but they aren't wet.

I only see fluid collecting near the front and near the black motor.

Edit:
Checked transmission fluid level it looks ok.
Checked tcase fluid level at the fill port, got blue fluid coming out right away so level looks good.