420 Rear Diff problems

The Iceman · 03-10-2010, 07:50 AM

Every time I go in mud, or water my rear differential fills up with water, and has a black sludge in the bottom when I drain it. its getting tobe a real pain in the @$$. is there something I can do, other than not go in mud? The Highlifter guys are putting trailer bearing grease in their rear diffs, but they also say to not go faster than 25-30 mph. I do an equal amount of trail riding and mud riding. Im contemplating whether or not I should grease my rear end!

shadetree · 03-10-2010, 08:33 AM

have you checked your rear seals ?..or what about your breather tube that is on your rear differental ?...most water problems are from bad seals..check those first...the grease has nothing to do with letting water in..thats a seal issue..at least that's what i've learned on working with water entering the differentals.

The Iceman · 03-10-2010, 12:08 PM

I havent checke the seals yet, b/c the bike is only 1 year old. I have all my breather lines going into my snorkel. from what I understand on the HL forums, the rear end in the 300 and 420 ranchers is a design flaw. (supposedly) but Im not sure. I gotta figure something out, changing the rear oil after every use is time consuming and annoyiing.

shadetree · 03-11-2010, 08:57 AM

i don't know about thier design flaw..what i do know is..if your going through alot of water and mud, i'm sure this isn't very good on your bearings and seals, as far as you having the breather tube for your rear differental going into your snorkle..i don't know why you whould have this going into that..your rear differental has a breather tube to keep the pressure from building up..and causing the seals to blow and leak..it's a small line..about a 1/4 inch in size..these need to be open to allow your differental to breath air and not put pressure on the seals..my guess is..even though your bike is only 1 year old..does not mean the seals are bad..muddy water can do alot of damage to your seals..i would at least check this out..and see if they are bad.

submarine 300 · 03-11-2010, 09:59 AM

I personaly would not put grease in the diff. what will happen is centrifical force will sling the grease away from all moving parts no matter how full you have it. Therefore leaving them dry without any lubrication. And it will not matter what speed you drive it will happen.............just my 2 cents.

shadetree · 03-11-2010, 10:10 AM

Quote:

Originally Posted by submarine 300

I personaly would not put grease in the diff. what will happen is centrifical force will sling the grease away from all moving parts no matter how full you have it. Therefore leaving them dry without any lubrication. And it will not matter what speed you drive it will happen.............just my 2 cents.

by noooooooo means..put grease in the differentals...as sub stated..this is the worst thing you can do..keep oil in it..as this will lube your bearings the right way.

Helmut · 03-11-2010, 11:09 AM

I have heard about the 420 Rancher having problems with the diffs leaking. I hear it's a bad design with the seals or something that causes them to leak.

Shadetree, the reason that he has the vent tube going into his snorkel is that he has his 4-wheeler set up for mudding and deep water. He probably has all his vent lines and overflow lines running up high to his snorkel to keep them above water.

submarine 300 · 03-11-2010, 12:25 PM

Quote:

Originally Posted by Helmut

I have heard about the 420 Rancher having problems with the diffs leaking. I hear it's a bad design with the seals or something that causes them to leak.

Shadetree, the reason that he has the vent tube going into his snorkel is that he has his 4-wheeler set up for mudding and deep water. He probably has all his vent lines and overflow lines running up high to his snorkel to keep them above water.

^^^^^^^Yep above the water. I've got all mine run up above the bars.

hondamechbrian · 03-21-2010, 11:09 AM

ya know, ive got an old antique sidewinder bush hog that the seal has been bad for over 30 years, weve been pumping grease in it for many years. still works.

on your problem, you have passed up the design for water depth i bet...lol. id check the seals as mentioned. check the oring on the fill plug. put some grease on it and grease the seals up good if you end up replacing them.