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Discussion Starter · #1 · (Edited)
I decided to write a guide on the problem areas with these trucks, and what to look for when buying one. It may also be a good read if you just bought one and don't know much about it yet.

Those of you looking to begin performance modifications, there is an excellent write-up stickied in the top of the Powertrain section, found here
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The Basics
Anyone who has ever owned a vehicle knows that maintenance is key. Whether the vehicle has 50,000 miles on it or 300,000 miles on it, if it was taken care of it is going to be a much better vehicle.

It is obviously very easy for the seller to replace some odds and ends right before putting the vehicle up for sale. So while looking to see if the filters look new/clean is a good idea, may not be a guarantee that the vehicle was taken care of.

Personally, I like to quiz the seller. I ask them question after question. When was the last time you changed the air filter? How often did you change the oil? What brand of oil/filter did you use? Do you do your own maintenance? If not, where do you take it to be serviced? When was the last time the fuel filter was replaced? Differential fluid? Etc, etc. Pretty easy to tell if someone maintains their stuff well or not just by asking some simple questions.

Also a good hard (but not beat-the-piss-out-of hard - drive it as if you intend to buy it) test drive will allow you to check for various problems. I will briefly give some things to look for in each section.

I like to look for leaks before and after my test drive. Once while it was just parked, and once after everything has warmed up and is still running.
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Problem Areas On These Trucks, And What To Look For If Buying

Transmission

The automatic transmissions can go either way. They usually will last 200-400k miles with simple maintenance, but a little bit of added torque or a lot of towing can push them over the edge. The cost to rebuild varies from one shop to the next, as well as by region.

The manual transmissions are fairly bullet-proof with one exception: The 5th gear nut. Basically, the nut that holds fifth gear on backs off the shaft and you will lose 5th gear. Generally there is no real damage, and it just needs repaired, but you will obviously not have 5th gear which is certainly an issue to most.

NV4500 5th Gear Fix
TSB on the 5th gear nut problem

Note: If you are looking to get a fair amount of added power to the wheels on your truck, plan on upgrading your torque converter and valve body with an automatic, or your clutch with a manual. The latter is much cheaper.
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Manual: Pay close attention to whether all of the gears work fine, do the synchronizers work well, etc.

Automatic: Pay close attention to shift points (early, late), as well as how the shift feels (mushy, firm). Note that an aftermarket shift kit will cause firmer shifts, and that's ok.
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Front End
Some report having issues with several front end parts including tie rod ends, ball joints, steering boxes/shaft, etc. The majority of these are fairly reasonable to replace if you are doing yourself, but it can obviously add up quickly on the other hand.

When needing to replace suspension parts, most will look towards an aftermarket heavy-duty brand. Moog, XRF and TRW being three pretty popular ones.
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If you are able to, jack the front end up. Check for play in everything you possibly can. Take the wheel side-to-side as well as top-to-bottom and wiggle -- if there is play, one or more parts are worn out and will need to be replaced.

A lot of this also can be tested during a test-drive. Does the truck wander all over the road, or does it drive nice and straight? Also note if it makes any unusual noises during turning, etc. This can be an indication of front end wear.
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The Killer Dowel Pin (KDP)
The killer dowel pin affects ALL 12 valves, and even some early 24 valves. Basically, there is a 3/8" steel dowel pin that aligns the gear housing inside of the timing cover. Due to the high amount of torque and vibration, this pin is prone to falling out.

Note: If it has not been fixed yet, this is one of the things you WILL DEFINITELY WANT TO DO as soon as possible, as it can be very catastrophic if it occurs. Also note that there is no correlation between mileage and when it happens. It seems to be completely random.

The kit to repair this costs ~$65 (It also can be done without a kit for around $40. It will likely take between 3-6 hours depending how mechanically inclined you are. It is not hard by any means though and is a DIY kind of job.

Killer Dowel Pin Fix Kit
Dowel Pin "tab" Dimensions
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Other than those few main areas of (maybe) concern, it is just normal things to look at, from suspension to interior to body etc.

Keep in mind that you will not find one of these trucks that rides like a cadillac like a newer one. They are built a little differently than the new ones (read:tougher :rof), not to mention they were designed for serious towing and hauling.

Fluid Capacities & Types


A/c Refrigerant: R134
2lbs

Automatic Transmission Fluid: Dexron III
17 Quarts

Differential Fluid: 80w90 generally, or 75w140 if you tow a lot, etc
Dana 60 Front: 3.15 Quarts, + 5oz of LSD additive
Dana 70 Rear (2WD): 3.5 Quarts, + 6oz of LSD additive
Dana 70 Rear (4WD): 3.9 Quarts, + 6oz of LSD additive
Dana 80 Rear (2WD): 3.4 Quarts, + 10oz of LSD additive
Dana 80 Rear (4WD): 5.4 Quarts, + 10oz of LSD additive

Engine Coolant/Antifreeze: Green or Yellow.
26 Quarts

Engine Oil: 10w30 or 15w40
11 Quarts w/ filter

Fuel Tank: Diesel :hehe
35 Gallons

Manual Transmission Fluid: Castrol Syntorq, Amsoil, or GM/Chrysler specific fluid - NOTHING ELSE
4 Quarts

Hope somebody appreciates the time it took to write that all up, and it limits some of the threads about this sort of thing. If I missed anything or you guys think anything should be added to it, please PM me and I will be sure to add it. Thanks.

Tim
 
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