Hello all, so I found out my wifes viscous coupler is bad per the dealership so I'm attempting to replace it with a junkyard coupler. Its hundreds of dollars cheaper. I also found out that the awd coupling oil pump can be replaced with a dorman part (number 600-221) but also for a couple hundred dollars. Long story short, I have to replace the oil pump as well due to a lack of available junkyard options, but It takes a fluid that appears to be a silicon fluid, not a typical oil. Does anyone know what kind of fluid it is specifically or where to buy it from?

Thank you

The tucson is a 2013 2.4L AWD

 

You might check in your owner's manual and see if it tells you the specific fluid to use. It may disclose the specified characteristics the fluid must have.
Otherwise that could be a "Dealer Item".

 

Just called the hyundai dealership. They say it's a sealed unit and dont have the type of fluid used.

My search continues.

 

If it is a sealed unit, that usually means you cannot add to it, replacement is the only option.

 

What happens if you replace the oil pump but lose some fluid? Since you can replace the oil pump.

 

I don't know the answer to that. What does Hyundai say?

 

Better late than never , but the fluid in all the couplers similar to this is TF 0870 or DTF1 or a bunch of other OEM part numbers used in Hyundai, Kia, BMW, Porsche, Landrover, Nissan etc This fluid is actually mentioned in their old manuals but no procedure on changing it. There is a fill plug on the front cover. On the back there is a spring loaded vent hole at the very top. If this is depressed with the unit down it will leak. The idea is when this is mated to the diff housing that plunger will depress and be a breather but for transport it is sealed.

Unless you know the mileage on a used unit I see no benefit in a used one unless it's really cheap and low mileage. Ex Korea these are about $710 USD with freight, they've come down in price in recent times.

Hyundai/Kia don't have these as a serviceable item but if you were really keen you could drain and fill these thorugh their life but would need removal to do so.

To replace a pump without fluid loss would require the assembly removed and held in a vice or in some way so the pump was vertical and that vent plunger in the rear is not depressed.

Identifying the quantiy though is a bit trickier. I'd say 500ml is ball park. In Hyundai/Kias tech data they refer to a total mass of teh unit filled and if it's out of spec assumed fluid loss they say replace it which is nuts.

I've used Ravenol mainly because that is what I could find

 

Something I just discovered, the fill porty on the updated coupler ending in 520 appears to be glued in where the early version ending 510 had a fill plug that was easily removed. I could not get the new plug out which leaves removing that cover off as an option and then using flange sealant to reseal it.

My 2014 unit has the fill plug, comes off easy, the 2022 new unit does not = mission impossible unless heated up real hot to break the locking sealant. Its also a different thread size