1. Would you folks recommend that even though the truck is under warranty that I replace the front driveshaft with the greasable variety sooner?
   
2. What precipitates the warping of the cylinder heads? Is there anything I can do to forestall the warpage, like change out the thermostat every 40K to prevent it from sticking, change the cooling system hoses every 60K to prevent failure, etc., or will the heads eventually just warp on their own from normal thermal cycling?
   
3. Some have said that having a place like Grease Monkey do the transmission flush and fill is a bad idea. Do others agree and should I just take it to the dealer for this service?
   
4. What else besides the manufacturer's recommended services can I be doing that will help prevent problems and lead to longer life?

quote:

ORIGINAL: Spike555

The head gaskets go bad because they are eaten away by bad worn out coolant.
LR recommends doing a cooling system flush every 45,000 miles or 3 years, whichever is sooner. Why do this with a 150,000 mile coolant?
Because it is corrosive. DexCool has a high acid content, it is a OAT (organic acid technology) coolant. What does that mean? It is "safe" for the enviroment. You get in a accident where does the coolant go? Into the ground. Then animals die and if it gets into drinking water...it kills fish, frogs, etc.
The problem with OAT coolants is the acid, it eats gaskets.
I used to sell coolant and every mechanic I talked to will tell you NOT to use DexCool.
If you notice that this happens only to DII''''s (which came with DexCool) and around 80,000-90,000 miles and the coolant was never changed before this point.
Yes get the front driveshaft rebuilt even though it is under warrenty. You do not want it to break on your wife while she is crossing a railroad crossing.