Transfer case leaking!

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hertahoe

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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.

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George B

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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

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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

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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

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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.
 

Fless

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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

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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!
 
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hertahoe

hertahoe

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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.
 

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