Gear box oil thickening

[Too wright]

I put up a few days ago how to change seals which I've done
I've ran the motor again on land with the motor running on a hose so the gear box was no were near the water , I checked the oil in the box after about 5 minutes of running and it was thickening again , any thoughts anyone
I am using ANGLOMOIL triple s 90 it is 100 % synthetic sae90 ,I've used it for years in my other outboards with no issues

[Yellowjacket]

Did you change the seals on the input shaft or just the prop shaft??? Water gets dumped into the tower and sits on top of the lower unit and can pass the seals if they aren't any good. Inspect the sealing surfaces on both of the shafts as well, if they are damaged or have corrosion issues you will eat seals in short order.

[hshawwpba]

I can help you with water passing into unit at prop shaft. I have found that water hits the front edge of the prop between the unit and prop, the faster the you go the higher the back spray pressure from this water against the seal and it will push into the unit. The simple solution is to install a Teflon washer between the seal and the front of the prop that is tight on the prop shaft surface make sure you leave slight clearance so it does not rub on seal. Remember the seal is made to keep grease in the unit, not to keep water out. It will stop seepage water but tends to allow water in under racing conditions as the water pressure will exceed the sealing ability of the seal and water leaks into unit.
Hope this helps.