Lubes: Have you replaced the other fluids before? If not I would replace the diff fluids. If it's 4x4, I would replace the xfer case fluid for sure. Your tk doesn't have P/S fluid, but for other guys with older trucks, I always flush the P/S fluids at high miles, at least before 150k Miles. 100k would be better. I just remove the return line (plug the nipple on the reservior), put some clear vinyl tubing on the return to a bucket. Suck all the fluid out of the reservoir with a suction gun (or baster). Fill with new fluid and have a helper start the vehicle while you pour as fast as you can. Stop when it runs 'clear'. I just did this job on a car 2 weeks ago. I just use OEM-suggested fluids. Mainly bc ya won't forget whats in there if you have multiple vehicles. An alternate is to put front wheels up on jackstands and turn wheel back/fourth, which I also do (before starting car). Usually figure 2 quarts. (that's for the other guys with older Rams).
- Brake Fluid: Definitely exchange the brake fluid. It absorbs moisture by design and becomes corrosive and doesn't perform as well as new. Fluid is clear and becomes darker the more moisture it's absorbed. If yours is the color of Beer, change it. Suck out the existing fluid, put in new, and bleed each brake (wheel) out in accordance to brake bleeding processes. You might want a shop to do this if you're not accustomed. If you run things dry, and don't have a scanner you can run into trapped-air issues. If you bleed gently you won't though.
- Antifreeze gets 'old' and corrosive. The PH could be real high on it and that can silently corrode your radiator and heater core (or engine). Aluminum makes a real good anode! he he. Problem is you have mixed metals of iron and aluminum. Iron likes high, aluminum likes low and there's a very narrow overlap (happy region). Therefore the 'safe' range of pH is very narrow. Back in the old days of copper radiators and heater cores corrosion wasn't a big deal. Copper is kind of a noble metal. Anyway, these days you do (or 'should'). Those test strips are terriblly inaccurate. A $12 China pH tester is much better. Commercial building operators with boilers test their boiler water Daily. I could tell you a ton of stories about customers I had who would install an aluminum heat exchanger boiler with their other boilers of copper and also had iron pipes. I'd advise against it. Most people struggle to keep that 'happy' range. Then bad things happen and the aluminum gets eaten away. A few years later they'd be calling me for another $40k boiler to replace the aluminum boiler.
I test/adjust each of my vehicles' antifreeze periodically to what they need to be. Classics with copper/steel have a wide range. But for steel/Aluminum, usually in the 8.5-9.0 pH range ..and test with a tester (that has been calibrated in known buffers). Increase acidity by adding citric acid or more 'basic' by adding Sodium Hyroxide (higher pH (more basic)) -- essentially a pinch or two of drain cleaner. Even new antifreeze out of the bottle, and purified water (don't use tap water) ...isn't the right pH for steel and alumium believe it or not. Antifreeze has inhibitors, but technically speaking if you want to take things to the n-th degree, set your pH.
- U joints: Block the wheels and put er in N. Then wiggle the driveshaft with vigor. If it's tight remove the rear u-joint and check the caps. Re-lube with the same type grease (don't mix a different type of grease with what you see there). The rear u-joint ususally fails first, so if it looks good spin the caps and put it back on. Otherwise you can put in grease then squeeze the caps with a c-clamp and usually force grease to the other caps.
- Door hinges; Lift up on the driver's door for hinge wear. Just to see. I wouldn't oil the door hinges. Chrysler has typically used a graphite impregnated crushed braided wire compound which wears well. When I've lubed them up (years past on Jeeps), they tended to fail sooner. So don't do that. But oil hood and maybe tailgate hinges.
- Rust Proofing: It would be a real good idea to get a heavy piece of wire and bend a little 90* hook on the end. Then remove the rear inner fender liners and run that hook up and scrape away any dirt that might be packed up around your boxes rear (inner) wheel wells. Sometimes a lot of dirt gets up there. That can rust out wheel wells. Remove any rust, then hose that area out on a summer day. Drive it and let it sit overnight or a couple dry days. Then squirt some oil up there to keep it from rusting. Same for the rocker panels. And the doors, tailgate too ..maybe front corners of hood if you are in a salty area. Or you can take it to a rust-proofer. Everyone has their voo-doo method, but I can say waste oil definitely works. And it's cheap and you have it. Otherwise Rams can rust bad under the wrong conditions, and yours is getting to that age.
- Relays: Might be a good idea to get a spare relay and throw it in your glove box in case something comes up you're prepared. My truck has 170k miles, and afaik the relays are all original. But I bought new ones to put in the glovebox just in case.
- I would go around to all your wheels and check ball joints and axle wear (lift up on axle).
- Check hoses and belts. Heck I think my 2012 has original hoses, belt has been replaced.
- Check fan clutch
- Inspect bushings for cracks
- Loosen and re-seat battery grounds to the engine and body. And clean battery connections. All electrical goes from neg to positive therefore bad grounds can cause a lot of wierd issues.
- Spark plugs (not sure if yours have been replaced) ....should check them.
- Touch-up paint chips
- Evaluate your upholstery. If you need to replace something do it now while seat covers are available. I just ordered a new OEM Mopar seat cover for my truck ...and foam. They wear out on the corners as you probably know. Those for my truck have been discontinued, but there were a few on Ebay. Clean the rest of the upholstery and condition if it's leather. Clean the carpet real well some dry, breezy summer day where it'll dry out well.
I'm sure guys can come up with a lot of things. There's recommendations in the back of your owners manual (or there are in mine anyway).
