1999 Chevy 1500 transfer case leak

ChevyDude123 · December 3, 2018

Hello,

This is a 1999 Chevy Silverado 5.3l, 4wd push button style, 4L60E transmission, 153k.

I have a green fluid leak (T-case fluid) coming from the front axel input shaft seal, drivers side. It obviously gets thrown around all over surrounding components when driven in current condition. The leak will accumulate about 2 or 3 drips on the ground overnight. It's been going on for a good while judging by the amount of fluid caked on everything. I've only driven approximately 50 miles since i noticed issue, all in 2wd. My questions are whether or not i risk significant damage to the case if ONLY driven in 2wd while also adding fluid as needed? Also, is there an "inner" seal in the transfer case that will be exposed when drive shaft is removed from t-case? If so, what is the responsibility of "inner" seal and is there a reason it should also be replaced simultaneously? When i'm in that deep i'd rather do whatever is necessary and logical.

Thanks for any help with stated questions and I also love to hear any related advice or experience! Taking it to a shop is not an option as I have little money and major trust issues. Trust issues stemming from several bad experiences in the past and most recently, pertaining to this vehicle. I bought this truck for $6,500, everything is in VERY good shape, recently had a 90k motor installed @ 150k (i purchased it at 152.5k) as a private party transaction from the auto shop owner who installed the second motor. Turns out recently installed engine either has a cracked head or head gasket as the black light test reveals coolant coming from exhaust among other confirmations... AAAGGGHH. That's a completely different story that's being dealt with but figured i'd share my reasons for NOT TAKING IT TO ANYONE mentality. Auto salesmen/mechanics can be total sleezeballs. From now on it's my way or the highway, to my own dismay haha.

Colossus · December 3, 2018

One of the few issues my old 99 had was that the transfer case fluid had mostly leaked out. There was very little left when I discovered that when going to change the fluid. Thankfully despite the low fluid level, it continued to work well for me after fixing it (and the eventual bad push button switch in the cabin) With your millage, it might just be worth going ahead and getting it rebuilt or getting a rebuilt unit. There will be plenty of them out there.

ChevyDude123 · December 3, 2018

2 minutes ago, Colossus said:

One of the few issues my old 99 had was that the transfer case fluid had mostly leaked out. There was very little left when I discovered that when going to change the fluid. Thankfully despite the low fluid level, it continued to work well for me after fixing it (and the eventual bad push button switch in the cabin) With your millage, it might just be worth going ahead and getting it rebuilt or getting a rebuilt unit. There will be plenty of them out there.

Okay thanks for the input! Glad yours didn't blow up with the low fluids. Im sure most major components are viable to be replaced at this milage (150k). But with that not in the budget im looking for information that would pertain to me getting in there and replacing previously stated seal. Is there a strong possibility of causing catastrophic failure (from related processes of getting into t-case i.e pulling driveshaft, unbolting hub, pulling axle flange bolts) that should deter me? Of course, the housing for seal could be damaged, which i wouldn't know until exposing it, which would force my hand buying a new one. So if anyone has any experience with these processes im all ears. I currently have time to burn and like being under my truck...

Supreme Pizza · December 3, 2018

Hi,

You said that the head is leaking - are you sure that the green fluid is not coolant?

You MUST pull the fill plug and check the fluid level if you want to ensure a long differential life. Even if the fluid leaks out, your parts will be fine as long as you keep topping it up as often as needed. I had a front diff leaking once, and I added 2 quarts of fluid per day to keep up with the leak. As for replacing the seals, I looked into it once - its not worth it. Its much more involved than you would think. Watch some videos of it before attempting it. My current rig has the same front diff as yours, and it was leaking as well. I fixed mine like this:

Remove drain plug

Drain fluid

Replace drain plug

Open fill plug

Add ATP-205

Top off fluid level with OEM recommended fluid

Immediately drive the vehicle in 4X4 mode for at least 300 feet

Drive vehicle normally

Engage 4x4 once per day for 100 feet for 3 days

Wipe any fluid off of the diff, to assist in fluid loss monitoring

Check fluid level as needed until leak stops

The ATP-205 fluid has worked VERY well for me. However - it may not work for you. There are lots of videos about it online - people trying it out and then posting reviews. I fixed my front diff leak, rear main leak, and an oil pan leak on another rig with this stuff. Its not an instant fix, read the directions - it can take up to 500 miles to fully work. It will not "Fix" a seal that is destroyed or completely worm out. What it does, is restore rubber to its proper condition. Ever seen dried out rubber that becomes tough and brittle? Soak it in this fluid, and it will become rubbery and pliable again like it is supposed to be. The seal may dry out and leak. Once the rubber is rubber again, the leak goes away. See why it cant fix a shredded / destroyed seal?

Supreme Pizza · December 3, 2018

As for your head gasket leak -

If your not blowing tons of fluid out of your exhaust, not mixing fluids, and you have enough compression for each cylinder to fire - this may solve your issue: Block Sealer.

You said that you can not go to a repair shop, and I assume you can not fix it yourself. Stop leak is the only option left. Yes, its has its ups and downs.

Some people (including me) would not want to use it in our own vehicle unless it was absolutely necessary. I have used it many times, and it almost always worked perfectly with no ill effects. The drawbacks are that it can sometimes cause other issues such as radiator clogging, etc.

ChevyDude123 · December 3, 2018

Starman thanks a ton for taking the time to share that info. As far as the green substance possibly being a coolant leak, I ruled that out because a) I can't find any signs of leakage anywhere on the exterior of the motor and b) the resevoir is filled with red coolant. I guess it's possible only the resevoir has DEX-cool and the actual cooling system is filled with green coolant, but unlikely that was the case in train of thought. I could only be sure by draining the cooling system and taking a peek i guess. Side note i've never owned a vehicle without a removable fill cap on the radiator itself, I thought that was pretty crazy when i first started diving into this ordeal. Just wanted to check level in the radiator itself and burp air off if there was any and was like, uhhhh...

I wasn't aware of the ATP-205 fluid. Like you I also try to stay away from "mechanic in a bottle" approach, likely why i've never heard of it but that sounds a whole lot easier than tearing everything apart, and in my particular case it's a no-brainer to give it a shot...if it it works, awesome. Worst case scenario I am back to square one..no love lost no love found. Thanks for sharing your process and what worked for you, although i could use a little clarification on the amount you used. On the ATP website it says one 8oz bottle ATP per 6 quarts of fluid for maximum effectiveness. There's about 2 quarts of fluid in t-case did you adjust accordingly and portion it out or just add the whole 8oz of ATP and top off to recommended capacity thereafter?

As far as head gasket issues, there will be more clarity soon. The exhaust doesn't do a HUGE puff of moisture in the morning although it does have a good amount due to temps in the high 30's low 40's in mornings. Never a solid stream of moisture coming out, you can however smell sweetness of the coolant in exhaust, captured tailpipe drip and it illuminates under black light. I don't smell any oil in exhaust or see the blue oily smoke, haven't owned the vehicle long enough to find out how much gets burned through. Driven it 500 miles. My next steps on that matter are drain oil and inspect, coolant system combustion detector test, maybe buy a compression gauge and test each cylinder...mechanic whom i bought it from claimed approximately 175 psi on each cylinder. Not sure if thats common on 90k engine but hindsight that might seem to good to be true at that mileage. Anyhow, thanks for the info starman i'm hoping you get back on the ATP amount you used for your case leak, and with any other input you have!

For anybody else reading please feel free to chime in on anything you'd consider insightful on these issues!!

ChevyDude123 · December 3, 2018

And yes, i'd likely be in over my head trying to do a head gasket job, although the vortec is one of the easier engines to do it on from what i've read. I have no engine/auto mechanic experience. Just 5 years of construction and hvac service work, gave me very good general diagnostic skills and attention to detail. Im a strong believer in "when there's a will, there's a way", but...... also admit i'm not at all educated on automobiles/engines specifically. Besides the 50+ hours of researching/youtube/forum scouring i've done this last 2 weeks HAHA. Darn truck.....headache city. I've learned a lot though.

Supreme Pizza · December 3, 2018

8 hours ago, ChevyDude123 said:

There's about 2 quarts of fluid in t-case did you adjust accordingly and portion it out or just add the whole 8oz of ATP and top off to recommended capacity thereafter?

Yep, just adjust the quantity of ATP-205 using a calculator. You can use more than needed, and it wont hurt anything - just don't go overboard.

Have you tried going back to the mechanic and complaining? If I sold someone a car, and they brought it back right away with those issues, I would attempt to fix it for free - or maybe trade them out for another rig. Unfortunately, MOST people in this world only care about themselves, and will not try to help you unless they have something to gain - so he might tell you to go away.

Replacing a head gasket is a major repair. It's also expensive. You have to pull the intake, pull the head, get a bunch of new gaskets, have the head pressure tested, have the head resurfaced, possibly valve some valve work, you have to deal with rusted / seized exhaust manifold bolts, new fluids, etc etc etc. Plus, there is no guarantee that the new head gasket will hold. Even if you torque everything properly and do it by the book, sometimes it doesn't work. When I come across a blown head gasket, I try the block sealer. If that doesn't work, I generally just swap the motor out for another used one. Small engines are a different story - they are VERY easy to change head gaskets on.

alpinecrick · December 30, 2018

If your front output shaft seal is leaking it can be a indication the front output bearing is going bad. Take a close look at the yoke where the shaft comes out of the case and note there is about an 1/8" clearance (if that much) between the yoke and the backside of the shifter motor. When that bearing starts wobbling it is not uncommon for the yoke to hit the motor. Besides destroying the motor it can also drain the fluid out of the T-case.'

In 2wd everything is still going through the T-case and fluid in the T-case is just as important in 2wd as 4wd.

I'm generally skeptical of magical potions in a bottle........there's almost always tradeoffs. Radiatior stop leak can stop up tubes that are corroded and already have restricted flow. Same with oil passages and filters in engines and trans. And in some cases stop leak fluids can and have affected the qualities of the fluids.

Hillwood · December 30, 2018

The photo you have is the front differential...
Is this where the leak is?
You talk about the tranfer case and green fluid??
Need a little clarity here.

Sent from my SM-G965U using Tapatalk

Hillwood · December 30, 2018

Hello, This is a 1999 Chevy Silverado 5.3l, 4wd push button style, 4L60E transmission, 153k. I have a green fluid leak (T-case fluid) coming from the front axel input shaft seal, drivers side. It obviously gets thrown around all over surrounding components when driven in current condition. The leak will accumulate about 2 or 3 drips on the ground overnight. It's been going on for a good while judging by the amount of fluid caked on everything. I've only driven approximately 50 miles since i noticed issue, all in 2wd. My questions are whether or not i risk significant damage to the case if ONLY driven in 2wd while also adding fluid as needed? Also, is there an "inner" seal in the transfer case that will be exposed when drive shaft is removed from t-case? If so, what is the responsibility of "inner" seal and is there a reason it should also be replaced simultaneously? When i'm in that deep i'd rather do whatever is necessary and logical. Thanks for any help with stated questions and I also love to hear any related advice or experience! Taking it to a shop is not an option as I have little money and major trust issues. Trust issues stemming from several bad experiences in the past and most recently, pertaining to this vehicle. I bought this truck for $6,500, everything is in VERY good shape, recently had a 90k motor installed @ 150k (i purchased it at 152.5k) as a private party transaction from the auto shop owner who installed the second motor. Turns out recently installed engine either has a cracked head or head gasket as the black light test reveals coolant coming from exhaust among other confirmations... AAAGGGHH. That's a completely different story that's being dealt with but figured i'd share my reasons for NOT TAKING IT TO ANYONE mentality. Auto salesmen/mechanics can be total sleezeballs. From now on it's my way or the highway, to my own dismay haha.

Hey Dude..
Are you sure you don't have a water pump gasket leaking coolant and dripping onto the front differential... That's what I see in the picture.

Sent from my SM-G965U using Tapatalk

ChevyDude123 · January 21, 2019

On 12/30/2018 at 10:22 AM, Hillwood said:

The photo you have is the front differential...
Is this where the leak is?
You talk about the tranfer case and green fluid??
Need a little clarity here.

Sent from my SM-G965U using Tapatalk

Hillwood... sorry about that. Yes it is the front differential not the xfer case. Drivers side. The pic is where the leaks at. It originates from the seal right behind the bolted flange so you can’t really see it in the pic. The fluid is green.

ChevyDude123 · January 21, 2019

On 12/30/2018 at 1:17 PM, Hillwood said:

Hey Dude..
Are you sure you don't have a water pump gasket leaking coolant and dripping onto the front differential... That's what I see in the picture.

Sent from my SM-G965U using Tapatalk

Yes I’m sure however the pic sure makes it look like that. But everything above is dry. dex-cool in cooling system so it would be red if so. I also thought it might be purging fluid out of the vent, which is also dry. It’s just that when driving it’s obviously spinning so it whips the fluid all over right there.

ChevyDude123 · January 21, 2019

On 12/30/2018 at 8:41 AM, alpinecrick said:

If your front output shaft seal is leaking it can be a indication the front output bearing is going bad. Take a close look at the yoke where the shaft comes out of the case and note there is about an 1/8" clearance (if that much) between the yoke and the backside of the shifter motor. When that bearing starts wobbling it is not uncommon for the yoke to hit the motor. Besides destroying the motor it can also drain the fluid out of the T-case.'

In 2wd everything is still going through the T-case and fluid in the T-case is just as important in 2wd as 4wd.

I'm generally skeptical of magical potions in a bottle........there's almost always tradeoffs. Radiatior stop leak can stop up tubes that are corroded and already have restricted flow. Same with oil passages and filters in engines and trans. And in some cases stop leak fluids can and have affected the qualities of the fluids.

Thanks for the good info alpine however turns out I’m an idiot and this is actually the front dif not transfer case. My bad man.

ChevyDude123 · January 21, 2019

Sorr for being unresponsive guys I’ve been busy training for a new job in another city the last month which meant two things. A) no money for repairs and B) no time for repairs. This upcoming week is my last week of training so hopefully after more feedback from you guys I’ll get on this in the upcoming weeks. Here are some better pics. The leak is from output shaft of differential. Hopefully you can see the green fluid drip there running off. The other pic just shows vent tube and general dryness of everything above although I get it’s just a picture and you can only see so much. But I’ve checked water pump and everything above- all dry. Ive done a heater core flush previously which is unrelated but point being coolant is in fact red. I pulled top plug on differential a few weeks back and when I checked it at that point, it was full of fluid. But I should probably check it again cause it’s obviously losing it haha.