About a month ago I started hearing a winding sound coming from my trucks rear end it goes away at higher speeds, I use the truck to pull my boat could water have got into the differential area, I also changed my e brake about 2 months ago.
Any ideas where should I start,thanks

 

Check the fluid. If milky,water got in .
You can put it on a lift and run it ,use a stethoscope to listen where the noise is coming from.

 

Will do, thanks

 

Ok I changed out the old gear oil and the oil was dirty no water little amount of metal on the filler screw, same sound...this truck has 270k miles and has been very dependable. I seen alot of post on buying a used rear end or rebuild the differential I have. Is the rebuild hard to do? And what kit would I buy or since the truck is very high mileage would buying a used rear end be smarter.thanks for any advise

 

A used diff can be easier and cheaper sometimes. Without tearing it down to see the damage it's hard to say.
If doing it yourself, price a salvaged unit and a reman .
Unless you have all the tools and knowledge,doing a complete bearing job can be expensive. If other parts are worn it gets even more expensive and complicated.
I'm doing one next week. Estimated cost for customer is about $1200 for me rebuilding it .

 

Yes and giving the age and milage, used or reman would be the best choice. Thanks for your input I appreciate it very much