oil in the water

[Flash]

You dont have to get a new radiator, just get an accessory transmission cooler and bypass the built in cooler in the radiator.

You won't have that problem again.

 

[radman]

Check TC Fluid

Although the transmission and the transfer case do not share atf there is the possibility that the vent hole from the trans. to the TC can allow some of this coolant to mix with the fluid in the TC. if the level get only a little bit over full in the trans.
Mike

 

[lobo411]

Although the transmission and the transfer case do not share atf there is the possibility that the vent hole from the trans. to the TC can allow some of this coolant to mix with the fluid in the TC. if the level get only a little bit over full in the trans.
Mike

Can this happen in an automatic too? I have a small amount of some kind of jelly-like brown substance accumulating in my radiator passages, but the coolant, oil, and ATF all look absolutely perfect. I checked my trans dipstick and I'm high on fluid, though--at the very top of the cross-hatch area while idling in park on a hot engine.

 

[SoNic67]

That's where it should be.
Are you sure the engine oil looks all right?

 

[radman]

I was talking about the automatic transmission and the all wheel drive v-8 configuration. There is no seal on the main shaft at the rear of the automatic transmission and no seal at the front of the transfer case.
There is a small (1/8") vent hole between these two units that will allow transmission fluids to get into the transfer case if the transmission is over full for any reason such as a leaking atf cooler.

The coolant system pressure can reach 13 psi with a properly working radiator cap but the transmission fluid pressure is slightly higher when the engine is running. While running, atf can be forced into the coolant system but after shut down the coolant pressure will push coolant the other way into the transmission cooler until the engine is completely cooled down. Eventually they will mix to the point that a transmission will fail. The reason for these failures is that the band and clutch friction material is bonded with a high strength glue that is water soluble and will allow that bond to come loose and you will find that friction material in the bottom of the pan.

That is the reason for using ONLY specified atf as other fluids are high in detergents and can also destroy the bans and clutches. An example would be the old type"F" fluid, never put it in our modern transmissions.
Mike

 

[lobo411]

That's where it should be.
Are you sure the engine oil looks all right?

Ya, it looks great on the dipstick, but I'll do an oil change in a couple of days. I'm doing a coolant flush now, and the ground is still soaked from that!

 

[lobo411]

I was talking about the automatic transmission and the all wheel drive v-8 configuration.

Ah...thanks! I have the 4.0 so I guess that's not my issue. Now that I've been playing with it, I wonder if I just had some radiator sludge. I discounted the idea because I've been good about flushing the rad way more often than required (every 2 years or so, even when I was putting 2000-3000 mi/yr on the car), but maybe that's not as big of a factor in sludge-prevention as I thought.

 

[jprentice94]

I got a new radiator and trans fluid was in the water it did not look like mine you could tell was mixed that looks like rust very badly . Mine also had the brown buildup on cap also had no signs of water in transfluid