[Doug D]

My responses in red:

I just bought a very clean 1500 quad cab 4wd with 108k mi on it yesterday. I want to drop all of the fluids and filters that I can get to. My question: are all of them necessary at this mileage? I plan on :

oil - change every 5K
radiator - recommended changing the coolant at 100K miles
brake lines - not sure what the factory recommends but every 2-3 years would be ideal
transmission recommended servicing every 60K miles - use ATF+4 only!
front diff - recommended servicing every 30K
transfer case - not sure
rear diff - recommended servicing every 30K
power steering? - maybe

.....I also want to do the DIY " HercuLiner" roll on bed liner - does anyone have any feedback on this product?

Can't advise you on the Herculiner bedliner. Mine is still a bare bed - haven't had the funds to get it lined. Personally I think spray on liners are best - the slide-in's can let water get between the liner and the bed leading to major rust issues.

What engine do you have?

 

[ImperialCrown]

Follow the Severe Duty schedule in your owners manual. If the vehicle's past history is unknown, err towards the side of caution and pre-emptive maintenance.
It can be much cheaper than a repair and should give peace of mind.
My brother in law has a color-keyed sprayed-on Rhino Liner that has given good service for over 10 years. I think that Ziebart applied it.

 

[MoparNorm]

I just bought a very clean 1500 quad cab 4wd with 108k mi on it yesterday. I want to drop all of the fluids and filters that I can get to. My question: are all of them necessary at this mileage? I plan on :

oil
radiator
brake lines
transmission
front diff
transfer case
rear diff
power steering? - maybe

.....I also want to do the DIY " HercuLiner" roll on bed liner - does anyone have any feedback on this product?

You can't go wrong, listening to ImperialCrown's advice.
I tried the Herculiner on a vehicle, saved a lot, for basically wasting every penny.
Translation it's a lot less cost for a lot less results, you get what you pay for.
I have a Rhino Liner in my Chassis/Cab that is in good shape, 12 years later.
The Herculiner, was applied exactly per the instructions, with hours of prep work. It's not very thick, even with repeated coats. It doesn't have the grip properties of the Rhino liner and it doesn't adhere as well, actually lifting and scratching in many places.

 

[jomadav]

Wow, thanks for all the feedback so soon. I plan on doing all the fluids as mentioned before still, just have to prioritize/ budget them. When I get to the radiator I want to do the T-stat at the same time just because it's over 100k....i.e. 15$ tstat + 20$ hose = 500$ tow from middle of nowhere during deer season.

Also, tailgate lock maybe. Apparently people want your ( mine ) tailgate. Any decent DIY stuff ? I have already looked into the MaterLock one and the Bully one.

Overall the truck is really tight, 1 owner and clean, all records too. Black on Black - only chrome is the grill.

The Herculiner project is underway already. Sanded and ready for a sunny day and 4 hrs open time. I know it's not the best, but the bed was trashed and I just want it covered and all the same color. I can always get a rubber mat if I don't like it, or a plastic fit liner. For the 69$ and some elbow grease I wanted to try it. Line-X here in Minneapolis is 500$ .

Only thing wrong so far is the driver side power lock cluster - window lock button is shot - same prob everyone else seems to have. I can control the other windows but they can't at the doors. I have to tear into it. I'm not fixing the switch, I plan to solder it permanently off and re-assembling.

5.7L HEMI single exhaust
HD towing group w/ brake controller and 6 pin
just added K&N drop in

 

[MoparNorm]

Just be aware that a plastic liner will move independently from the bed and after a few months it will remove nearly all of the bed paint and leave you with a rusty mess underneath.
Yes a spray in liner is $500, buts its done and forget about it.
You can screw around with several cheaper methods but in the end you'd spend $350-$400 and not have satisfying results.
Spending $500 once, can be cheaper in the long run.

 

[AC TC]

power steering? - maybe; do a turkey baster change and have a look of the old oil, you will never regret that change.
transfer case; same as the axles, it uses atf i belive.