With water levels down on the lake I ski on and a gradual ramp I am required to back my truck a long way into the water so that I can get my boat off the trailer. 4 times since September my rear differential has been "dunked". The water is almost coming into the bed. Typically the truck has sat overnight and has cooled down and then the next morning we drive 1/2 mile and put the boat in so the rear diff is not hot when it hits the water.

Am I in a position where I should be dumping rear diff fluid monthly?

Do I have anything to worry about?

I have not looked at the diff yet, is it easy to check the fluid level/colour?

Chief

 

If I remember correctly, the owners manual says that you're suppose to change the fluid if the differential has been submerged

 

If you pull the filler plug on the diff and the fluid is NOT milky then you are golden.

 

Yep - owner's manual and maintenance guide.

Launching or retrieving a boat
Disconnect the wiring to the trailer before backing the trailer into the water. Reconnect the wiring to the trailer after the trailer is removed from the water. When backing down a ramp during boat launching or retrieval:
• do not allow the static water level to rise above the bottom edge of the rear bumper.
• do not allow waves to break higher than 6 inches (15 cm) above the bottom edge of the rear bumper.
Exceeding these limits may allow water to enter vehicle components:
• causing internal damage to the components.
• affecting driveability, emissions and reliability.
Replace the rear axle lubricant any time the axle has been submerged in water. Rear axle lubricant quantities are not to be checked or changed unless a leak is suspected or repair required.

If the transmission, transfer case or front axle are submerged in water, their fluids should be checked and changed, if necessary.

Driving through deep water may damage the transmission.
If the front or rear axle is submerged in water, the axle lubricant should be replaced.

Your vehicle’s rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants do not need to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water. The axle lubricant should be changed any time the rear axle has been submerged in water.

Normal Vehicle Axle Maintenance
Rear axles and power take off (PTO) units containing synthetic lubricant and light duty trucks equipped with Ford-design axles are lubricated for life. These lubricants are not to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water. The axle and PTO lubricant should be changed anytime the axle and PTO have been submerged in water. During extended trailer tow operation above 70°F ambient and wide open throttle for extended periods above 45 mph, non-synthetic rear axle lubricants should be replaced every 3,000 miles or 3 months, whichever occurs first. The 3,000 mile lube change interval may be waived if the axle was filled with 75W140 synthetic gear lubricant meeting Ford specification WSL-M2C192-A, part number F1TZ-19580-B or equivalent. Add friction modifier C8AZ-19B546-A (EST-M2C118-A) or equivalent for complete refill of Traction-Lok rear axles (see Owner’s Guide for quantity). The axle lubricant should be changed anytime an axle has been submerged in water.

 

Wow
This is a pain in the ****. So for the avid boater with a poor boat launch he must change his rear diff fluid 30-40 times per year!!! ??? WTF?

Thanks for the response. I guess checking the manual should have been my first stop.

Cheers

 

Or run the vent tube higher and pull the plug check for contaminated fluid on occasion. It is not a regular occurrence to submerge your truck to unload a boat. You may want a custom trailer that lowers the boat or with a telescoping tongue. The local trailer shop here Texas RoadRunner makes awesome custom trailers.

 

That's what I was going to say. I know a lot of serious off-road guys run both diff vents into the engine compartment to avoid a hot diff taking a big gulp of water. They put fuel filters on them to keep the junk out.

 

Good ideas guys. I don't have the $$$ for a custom trailer. The trailer used for a nautique are custom already to accommodate the direct drive set up - but there is always room to improve if you have the money. I uploaded pics of my new slalom boat hooked up to my screw.

So am I safer to "dunk" the differential when the diff is cold?

 

Yes, but make sure that the breather tube is high enough that it won't allow water to be sucked in.

Also if you have any seals that are weeping/leaking the hot diff could suck water at that point.

Just check the fluid real regular and if it looks like a milk shake then you have an issue. Other than that you should be good to go. IMHO

 

as a former avid offroader in the world of jeeps i can tell you that there is no way for water to get inside your differential otherwise through the breather hose. i would check to make sure you are okay as of now, but in the future i would run to lowes and get the proper tubing to extend your breather hoses (both diffs, t-case, and transmission) to the top of your fire wall, just below your windshield.

 

Thanks Marshal

 

Nice boat. I have a 2005 Nautique Super Air 210.

 

I checked my t-case and the fluid is perfect. I am a little concerned checking my rear differential. Do I only have to open the one check hole or do I need to loosen all of the bolts on the rear of the differential?

Thanks OK wakebdr. Just had to put it away for winter. Correct craft has got to be one of the highest quality boats around. This is my second one.

We skied all weekend so we got a long season up here! Water was 51 degrees :-)

 

I'm not sure this is the "sanctioned" way of checking the diff fluid, but I just open the check hole, stick a clean finger in to touch the fluid and see what comes out. It's usually really obvious. clear=good, milky=very bad

If you loosen all the bolts on the rear of the differential, you'll likely leak fluid and need to replace the gasket. Just FYI.

 

The breather tubes on these trucks are firmly connected to one of the cross members under the bed, several inches above the differential. You should be good to go unless you dunked half of your bed.