So I went out and bought me a new 5th Wheel, from what I am reading I should be changing the rear diff fluid to a 75/140 gear lube. My question, will changing to this heavier lube create any problems when I am not towing?
It is safe to say that 90% of the miles I put on, I will not be towing.

Also, front diff any upgrades required there? Is that front cover a pain to remove? I am due for front diff fluid change and I will be upgrading to synthetic.

I switched to 75w140 when I bought my 5ver as well. I'm not sure if I had it to do over again that I wouldn't just stay with the stock synthetic. I seem to have a bit more gear whine with the heavier lube, also developed a rear seal leak which is probably unrelated but I'm whining about it anyway! ):h

Front diff is a must, synthetics always good. Mama JJ forgot she had four wheel drive engaged and pulled our 5ver several hundred miles at 70mph before realizing it. :eek: She did comment on just how well it was pulling the long grades, at 70+ mph. Dang woman scares me sometimes!

What kind of 5ver did you end up with? Post some pretty pictures when you get a chance. Later. JJ :)

You dont need to yank any "cover" up front? Also dont need to yank the rear cover, just pop out the plugs.

IMO mobil 1 75 90 w up front, make sure you have the white plastic vent deal, if not change it to the white one.

Michigan can get pretty cold, and since most of your driving is unloaded I may be more apt to stay with the lighter 75 90w but I duno??? Maybe getting a magtech cover for the back or something if your worried about things and running the normal oil??? I duno, I dont tow.

How heavy is the 5th wheel, were do you tow it? Generaly just tow in the summer???

Bought a 2005 Wildcat 31QBH. Should weight right around 10,000lbs when loaded. I will pick it up in one month, hope to post pics shortly thereafter.
Will be towing all over, mostly heading west in late summer early fall.

I looked at the front end and did not see a drain plug, perhaps I should look a little closer.

Yes the front is a plug, no "cover" like the rear. Might be easier to get at if you drop the shield but I cant remember, its been awhile since i changed the front end juice.

Also the rear has plugs for draining and filling. Dont need to yank the cover there, the drain for the rear is on the bottom.

G80 info:
http://dieselplace.com/forum/showthread.php?t=3374


Front axle converted to 75W90 in cold climate:
http://dieselplace.com/forum/showthread.php?t=515