Help! Center diff leak?

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I appreciate the opinions and advice. Everything seems ok but I’m still frustrated at not knowing what happened and why. Today I got the truck on dirt, engaged 4 low, crawl etc as I did the first time. I checked under the truck then & also since being back and no problems.

There is oil residue from the previous leak where my thumb is in the pic. There is oil residue on the exhaust pipe and a burned spot you can kind of see in my original pics above. There is absolutely no oil anywhere else...the transfer case, all surrounding areas are completely clean.

Questions: is there a seal in that part of the drive shaft? Is there oil in there to begin with? Really hoping to figure out what happened.

Thank you

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No seal, no oil in that location. With oil right there, I'm still voting for oil coming from the seal on the shiny part of the DS that's just to the right of your hand.
 
Sandroad said:
No seal, no oil in that location. With oil right there, I'm still voting for oil coming from the seal on the shiny part of the DS that's just to the right of your hand.
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So there’s oil in the shiny part? From where? Is there a seal to the right of the shiny part in my pic? If so, where is that oil coming from? That’s a long way from rear diff, and I thought there was a seal between transfer case and drive shaft? Forgive my cluelessness. Is there a seal there that could have failed?
 
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JohnPW said:
So there’s oil in the shiny part? From where? Is there a seal to the right of the shiny part in my pic? If so, where is that oil coming from? That’s a long way from rear diff, and I thought there was a seal between transfer case and drive shaft? Forgive my cluelessness. Is there a seal there that could have failed?
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Yes there is grease inside your drive shaft's slip yoke. If too much is put in it can damage your drive shaft seal or your driveline components as it's not compressible. The easiest solution is to unscrew your zerk fitting and compress your suspension to remove the excess grease.
 
Supra88 said:
Yes there is grease inside your drive shaft's slip yoke. If too much is put in it can damage your drive shaft seal or your driveline components as it's not compressible. The easiest solution is to unscrew your zerk fitting and compress your suspension to remove the excess grease.
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Thank you so much. What came out all over my garage floor was several ounces of yellow tinted oil, not like any grease I’m familiar with. Would that make sense?
 
If it was gear oil it would stink your whole garage up. Same with transmission fluid. If it doesn't smell it's likely grease. Grease will naturally separate it's solids and liquids. The liquid portion of the grease is going to make its way through the seal first. If it's overfilled something has to give. Your differential internals or the seal. Without seeing it, it's hard for me to tell. If it were me I'd want to relieve any excess greas in the slip yoke before doing more damage. Removing the zerk is a 30 second job. Do that and bounce up and down on your 200 to cycle the suspension. See how much grease shoots out. Reinstall zerk.
 
Get some Brake Clean and clean the area up and see if the leak reappears. Put a drip pan under the area so you can isolate and identify the liquid?
 
JohnPW said:
So there’s oil in the shiny part? From where? Is there a seal to the right of the shiny part in my pic? If so, where is that oil coming from? That’s a long way from rear diff, and I thought there was a seal between transfer case and drive shaft? Forgive my cluelessness. Is there a seal there that could have failed?
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When you're under there, did you see the grease fitting (zerk) on the driveshaft? The grease is in the part of the driveshaft with the grease fitting. The grease cavity is only as long as the splined slip joint that allows the length of the driveshaft to change as the suspension flexes. Those splines inside the driveshaft are lubed by that grease, not oil from the differential or T-case. There is a seal between the part of the driveshaft with the grease and the part of the driveshaft without the grease that keeps the grease in. Where the seal rides on the driveshaft, it's shiny. If the oil separates from the thicker carrier material in the grease, it can leak out of seals. That's not unheard of and some greases are more prone to separation than others. If the grease cavity was overfull, some oil might have been forced out. Hence the recommendations above to remove the grease fitting (zerk) and see if any grease/oil comes out.
 
Just looking at the puddle you posted in your first post, I don't believe there is any way that quantity of oil comes from separated grease in the slip yoke. The system doesn't hold that much grease.
 
tominboise said:
Just looking at the puddle you posted in your first post, I don't believe there is any way that quantity of oil comes from separated grease in the slip yoke. The system doesn't hold that much grease.
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Maybe, but before I learned that Mobile 1 was one of the greases prone to separation, a partial tube of that left a large puddle of red oil in the bottom of the tray I keep my grease guns in. Easily as much as in the OP. It may not be separated oil on that driveshaft, but it had to come from somewhere.
 
Thing is, basically all grease used on driveshafts is colored and I’d expect any oil separated from that grease to be colored as well. The dyes they use are quite potent.

Also I have no clue how people are concluding that the driveshaft has been overfilled.

OP, get under there and remove the outer guard around the transfer output. ~4 12mm bolts. It won’t hurt to drive it a bit with that removed. Pull the transfer case fill plug (the one about halfway up the case, not the drain near the bottom) on level ground.. fluid level should be right at the bottom edge of the hole. Any extra needs to be drained off. Clean the area really well, including the exhaust and brown drop on the bottom, which to me looks like fluid has been dripping there and burning off for a while. Clean the driveshaft. The seal in there is in the larger diameter raised area up against the clean non-painted metal section.. the clean area slides in and out. It is normal to see some grease at the seal and on the clean metal part, the driveshaft has grease added through the zerk then centrifugal force makes it flow around to the splines and normal suspension cycling allows it to distribute evenly and slowly pump out that seal. You should see a line of old grease under the truck roughly lining up with where the driveshaft seal is, being flung out slowly for all these miles.

And, have your wife smell the fluid to see if it’s gear oil.

If the case were actually leaking that much I’d expect to see a mess all over the bottom of the case and crossmember. If it were coming out of the driveshaft I’d expect to see a mess all over the bottom of the truck, not neatly dripping on the exhaust and running down.

That’s all I’ve got
 
IT IS OFFICIAL. I AM AN IDIOT. I have found the source of the thick fluid on the driveway & exhaust. I appreciate everyone’s thoughtful and knowledgeable responses and advice, but the actual fluid was half-dried Sprite from the coolbox!

I opened the coolbox today and there was an unopened Sprite can that was left there weeks ago. Somehow that unopened Sprite can sprung a leak, and the unopened can was completely empty. The coolbox was a sticky, moldy mess that took some time to clean out, but there was far less than what 12 ounces of dried Sprite would leave. I now realize the thick, oily fluid was half-dried syrup of that Sprite.

I dumped some water into the coolbox, and the water escapes through vent holes in the front of the coolbox near the bottom...and leaks down onto the drive shaft and exhaust, exactly where the original goop was.

When I cleaned up the original mess on the driveway, I used a lot of Dawn and a hose. It was an easier clean up than I expected...I now know that’s because it was water soluble Sprite, not oil or grease. I feel like a moron.

I didn’t know the coolbox would drain. I don’t ever put opened drinks in there. I now know it drains straight down below the vehicle. Attached is the unopened, but empty Sprite.

Thanks again for all your help.

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Congrats on the self diagnosis and the willingness to share it with us. Cost effective too!
 
This truly didn't make sense.. but now it does. Glad you got it sorted.
 
I am very surprised that liquid will flow immediately out the bottom of the vehicle if something is spilled in the coolbox. I would assume there wouldn’t be an easy escape for liquid, as that would mean cool air would also escape under the vehicle?

Is there a negative effect of syrup from a Sprite venting through the coolbox (Beyond my current ordeal in thinking I had a fluid leak)? I figured rinsing water through there can’t be any worse than syrup. I have no clue on the plumbing of a coolbox . Anyone have insights on this? Thanks.
 
JohnPW said:
I am very surprised that liquid will flow immediately out the bottom of the vehicle if something is spilled in the coolbox. I would assume there wouldn’t be an easy escape for liquid, as that would mean cool air would also escape under the vehicle?

Is there a negative effect of syrup from a Sprite venting through the coolbox (Beyond my current ordeal in thinking I had a fluid leak)? I figured rinsing water through there can’t be any worse than syrup. I have no clue on the plumbing of a coolbox . Anyone have insights on this? Thanks.
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The cool box has an evap core just like the AC so it would need a condensate drain as well. I’m betting that sprite just drizzled out of there as if it were collected humidity during operation.
 
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