could use some advise!,, got a 04.5,,it"s a great truck and I"m getting great mileage ( 21 on hyw) how ever,,i live in wisconsin ,,lots of salt on the streets in the winter,,this truck has absolutly no under coating at all,,so i picked up some under coating and a spray gun for it at a local auto paint supply store ($53.00) worked very well! proud of myself for saving so much money! I sprayed it on the rear differential ( becausr they rust and look like crap after awhile)and now I"m wondering if that was a good idea! now I"m thinking that maybe it will get hot because of the coating on it,,u know,,affect heat dissapation,,,,can anyone give some insight on this? done alot of searches and came up with nothing,,,,,,thanks,,,,,ed

 

I wouldn't worry about it. If the coating peels off due to the heat, let it be - even though it may look like crap. The good news is that you did it at the right time, when its new and have minimized any buildup of dirt&grime.

Try a search on this site using the word "undercoat" - in all forums and all dates. You'll get about 15 threads.

I think our trucks are already coated from the factory - the sheet metal stuff is; I could care less about the diffs and tranny not being coated. Mine's been through 2 winters of salt and they (truck and diffs) don't look any different than when it came home in October '02.

You were referring to rustproofing, right? (based on your concerns of rusting from salty winter roads in WI). I see rustproofing and undercoating as two different but related subjects. I grew up in MI which is another one of the kings of salty roads.

 

i used RUSTFRE UNDERCOATING with fiber and rust inhibitors, it"s also rubberized,,,looks and smells alot like tar to me!
it looked like the sheet metal for the underbody was treated,,but because the sheet metal is so thin,,i wanted added protection( this bad boy cost alot of money) against stone chips that I"m sure would cause rust,,also sound deadening( doesn"t sound any quieter in the cab) either way,,it can"t hurt nothing.
my concern was heat build up in the differential from it being coated,,ur the 2nd person who told me that it"s no biggie,, i do thank u for ur reply,,and I"m not gripped with paranoia about it anymore,,,
,, also, I"ll try the search,,,
Hows the amsoil working out for u? only have 2600 miles on the truck, so I"m still on regular oil,,but when it"s broke in ,,i plan on switching to synthetic,,just don"t know what kind yet!
thanks again pal!

 

On any differential you want heat to disapate as quickly as possible, so I would not put anything that had insulating properties on any part of the driveline.

 

, I"m gripped with paranoia again!!!!!!!!!!! think I"ll just take it off the diff. , that way I won"t have to worry about it anymore,,better safe than sorry!,,,thanks for the advice.
i see ur truck was built the same month mine was,,,,how has she been treating u?,,,how many miles on her? any problems?

 

Ed: I have 1400 miles on it now. MPG started out at 13, last was 15 empty. Hopefully mpg keeps on going up. Towing at 19000 gcvw for 500 miles was 10.2 mpg (filled to neck every time)

Problems so far:
- both door seals are ripping at the mirror level,
- shudder in 2nd gear with clutch fully released until rpm gets up to about 900 to 1000,
- some noise in transmission that I attribute to the miss/knock/tic at low rpm and it causes a rattle unless accelerating
- some lights do not come on during check light at start

Happy with it so far, but have not taken it back to dealer for corrections yet. Did take it back so they could observe rattle and knock/tick but it was recommended I monitor it for now. They did say they have received bulletins lately from DC stating customers are complaining about various noises and it is probably due to the fact the 325 is so quiet.

 

krown rust control products is what i am getting my truck sprayed with yearly...