My '08 Hemi 1500 just rolled over 60,000 miles, so I'm getting ready to do some maintenance and wanted to get some input from others. I bought the truck used with only 16,000 miles on it. At ~45,000 miles, I had the front and rear differential fluid and transfer case fluids all replaced, and I had the transmission pan dropped, filters replaced, and topped off with new fluid. This work was all done at CarMax since the truck is still under warranty through them and though I typically do most of my own maintenance stuff, I'd prefer to have record of them maintaining it while the warranty is good to prevent any finger pointing if I have a problem.

So now my question is, should I bother with replacing the differential fluid again now, and should I get all of the transmission fluid exchanged? It's only been about 15,000 miles since the last work was done. I know the owner's manual suggests 18,000 mile intervals for differential fluid, but I rarely tow or haul anything and have seen some discussion here about 30,000 mile intervals. I'm tempted to just suck the existing fluid out with my hand transfer pump and put fresh fluid in, but I'm also paranoid about the LSD retainer clips failing in the rear differential, so I suppose it would be good to pull the rear differential cover off periodically to inspect things.

CarMax is now telling me they no longer do transmission fluid exchanges, and everyone else I've called does flushes, doesn't want to remove the pan and change the filter (one shop I spoke to actually refused to simply drop the pan and change the filter without also doing a flush, and said changing the filter isn't necessary!), and they all want $250-$350 to change the differential fluid. That's outrageous. So I may be doing some or all of this myself.

Also, I'm not planning to fool with the transfer case fluid again for another 15,000 miles (30,000 mile intervals, right?), and the spark plugs were replaced at about 38,000 so I'll probably give them another 8,000-10,000 miles, too.

What say you guys? Am I wasting money changing fluids this frequently, or is this good insurance against future problems?

 

The owner's manual will cover all your questions. Anything over $150 is outrageous for fluid change on two diffs. Do the drop 'n' drain + filters on the tranny. It'll want about seven quarts. The plugs are good for at least another 20K.

 

Actually, the owner's manual is what has me confused. It suggests changing the transfer case fluid, transmission fluid, and filters at 120,000 miles (or 60,000 miles if you use your truck to tow frequently). That is crazy, in my opinion. It also suggests differential fluid changes every 18,000 miles if frequently towing. I don't do any frequent towing (maybe 9-10 times a year for 30-40 miles each round trip). So it's unclear to me how often I should be doing these fluid changes.

I couldn't agree with you more. The dealership wants $600 for front and rear differential service and a transmission flush. Obviously that is not happening.