Help please trans issue

[Tahoeman1120]

Okay so had an issue with transfer case I replaced the transfer case and after I did my girl was driving the truck and smelled transfer fluid burning I checked the fluid it's black and burnt I'm not entirely sure what's going on but any ideas as to what caused this ? The truck still drives no issues cold the trans to this day has never slipped or knocked nothing but if it's driven when it gets hot it makes a lot of noise but I think the noise is happening because it's overheating and cooking the fluid and making it lose its viscosity but any ideas would be very helpful I'm just hoping it's not the Trans the truck has almost 400k on it and the motor is still very stout idk if the Trans cooler isn't functioning properly or what but please don't hold back from your feedback has anyone else ever experienced problems similar to this?? It's the 4l60e

 

[Tahoeman1120]

The truck is a 99 btw

 

[swathdiver]

So do you suspect the transfer case or the transmission?

If transfer case, it is possible that the pump and pickup tube were not installed correctly.

If the transmission, it is possible that the external lines and cooler have become clogged over the years and the flow is much reduced leading to failure of the transmission.

 

[Matt Wilson II]

Possible clogged cooling line from corrosion over time?

 

[Tahoeman1120]

So do you suspect the transfer case or the transmission?

If transfer case, it is possible that the pump and pickup tube were not installed correctly.

If the transmission, it is possible that the external lines and cooler have become clogged over the years and the flow is much reduced leading to failure of the transmission.

The transfer case was used from a junkyard I drained the old fluid and put the good stuff back in never took it apart because I know nothing about rebuilding them I suspect the transmission I do know the transfer case was freely spinning before I installed it it wasn't seized or anything

 

[Tahoeman1120]

Possible clogged cooling line from corrosion over time?

I will have to check that one out is that something that could just randomly happen or would there be signs before it happened?

 

[Tahoeman1120]

So do you suspect the transfer case or the transmission?

If transfer case, it is possible that the pump and pickup tube were not installed correctly.

If the transmission, it is possible that the external lines and cooler have become clogged over the years and the flow is much reduced leading to failure of the transmission.

So I guess now I will pop off the cooler lines to see if they seem to be clear I'm nervous to drop the trans pan I'm not really trying to sink alot of money in the truck if it's too much ill just have to sell it I'm hoping it's something simple

 

[OR VietVet]

The two systems run different fluids, correct? The transmission cooling lines are not gonna effect the transfer case, right? Been too long since in the shop and too lazy to dig for info and I am 4 Jim Beam and waters in to the night.

 

[OR VietVet]

So I guess now I will pop off the cooler lines to see if they seem to be clear I'm nervous to drop the trans pan I'm not really trying to sink alot of money in the truck if it's too much ill just have to sell it I'm hoping it's something simple

Wait, wait, wait...what fluid is black/dark...the transmission or the transfer case? How do you know the difference between transmission fluid and transfer case fluid smell burning?

 

[exp500]

Bad Tcase from junkyard, possibly the wrong one. Post pic of the codes on glove compartment door.