"Refreshing" a 2002 Jeep GC 4.7

[HawkeyeScott]

My retired mom and dad in Iowa recently bought a 2002 Jeep Grand Cherokee to be sort of a spare vehicle. Looks like it may soon become a daily driver. I'm curious to know what you guys would do to get it road ready. Here are some details:

- Limited model. Interior and exterior in great shape. Looks brand new under the hood.
- 113,000 miles 1-owner miles.
- tranny fluid an ugly brown
- engine oil just changed
- very few maintenance records outside of a few oil changes that show up on Carfax
- car spent most of its life in central Illinois

I've read about this engine having a tendency to sludge. Should they AutoRX or Marvel it? I've suggested a new tranny filter and to flush the fluid. I would change out the rear and front diff. fluids, as well as the transfer case.

Anything else? How about an oil suggestion?

I think they have a good car. I just want to help them "refresh" it to maximize its reliability.

Thanks a lot.

 

[joel95ex]

basically focus on cleaning up the insides:

replace trans fluid---either drop pan method or do several suction/refills.

Replace the oil---to clean up, just use PP, PYB, or MC5K and a wix or pureone filter.

Flush and refill coolant using the garden hose method--be sure to bleed air

I would also replace the rear diff fluid by suction

spark plugs....

Get a haynes manual since it shows pretty much everything for routine maintenance and specs.

and then inspect belts, hoses,

 

[HawkeyeScott]

Joel - Thanks.

How has your 4.7 performed? I just had a buddy that totaled a GC with this engine, at 208K.

 

[Mr Nice]

How about some Auto-RX ?

 

[DieselTech]

Dont use additive, get some PP and a P1 filter. and let the oil do it's job. Drop the pan and replace the trans filter, clean the magnet and then do a complete fluid exchange. If that fluid is brown likley the filter is junk, and the fluid is high oxidized. This is horribnle for valve bodies, torque converters and trans coolers. need to get all of the fluid out and start fresh.

Time for plugs
rear diff service
fuel filter
air filter
cabin air filters
brake fluid flush
run a bottle of redline sl-1 through the fuel tank
check PCV valve
Check the belts and hoses
Flush coolant system

After this you should be set for a good daily driver.

 

[joel95ex]

this version of the 4.7 is supposedly different, but my boss had the first gen durango and seized it---but I don't think he was as anal about oil. I saw the sludge that the machanic removed and it looked like hot asphalt....that was before the seizing. so IMO a previous version 4.7, I would for sure be focused on cleaning. I have used ARX on both my vehicles before and do think it helps clean up, but IMO you could just use dino for a few shorter 3-4K intervals and throw in some MMO for the last 500 miles or just switch to PP and go 5K a few times and not have to deal with additives---if the vehicle is not in your posession all the time, it is very difficult to monitor things, so an oil known for cleaning may be the way to go for you.

 

[sparkplug]

Flush and replace the coolant. Change the trans fluid and replace BOTH filters. Differentials need to be serviced. 75w140 weight is you tow but really 80w90 is fine. A good synthetic oil with a pureone filter is fine. Replace the sparkplugs. Since it's not an H.O. use the factory Champion copper plugs. Replace the fuel and air filters and bleed the brakes. Replace the pcv valve. Things should be set then.

 

[JimPghPA]

Also when you replace the plugs put new plug wires on. Go over the brake system, and flush brake fluid, PS fluid, and if you want them to get years of good service from it replace all the vacuum lines, and windshield washer lines. Add a large inline metal fuel filter if the vehicle only has a small fuel filter. I do not know if that vehicle has a clutch fan, but if it does replace the clutch for the fan. The clutch for a clutch fan has break shoe like material, with that many miles they are gone. If it has a clutch fan it will overheat with a worn clutch.

You might want to add a rough thick black paint to the lowest 6 inches and around the inside of the wheel wells.

 

[JimPghPA]

Check the rag joint/universal joint between the steering wheel and the steering box. If it has slop, replace it.

Put 4 new shocks on it. Do not spend money for expensive shock use one grade above the lowest cost. Expensive shocks stiffen up the ride so much that it makes that type of vehicle have too rough of a ride.

Then have a good alignment shop go over it looking for worn front end parts, and get them to grease and align it. Do not go with a department store or a tire store alignment. They just move them in and move them out and do not find bad front end parts.

Pack wheel bearings if any (I am not familiar with that vehicle).

Clean the comutator and replace the brushes and bearings in the alternator. Clean the comutator including the little groves between each section on the starter and replace the brushes, and bendix. Put grease on the areas where moving parts contact but do not over grease the starter when assembling.

Clean the battery connections, and if the battery is 4 + 3/4 years old, replace it with the highest CCA largest Interstate brand battery that will fit in it.

If any of the light bulbs have a back tint to them they are about to go. Those ones I would replace.

Check that the heater blows enough heat. Sometimes older vehicles have the insides of the heater core clog. If it is clogged it might unclog when you flush the cooling system or it might require you to concentrate a flush on the heater core, or it might not unclog and you would have to replace it. Plenty of heat is a must for older people.

 

[VNTS]

Is it a Limited or Laredo

ANyhow, it is coil on plug, use champion copper plugs, the champ truck plugs are good. Yank the TB and clean that up. Replace the PCV with a mopar.

The trans is the 545RFE, has two filters, a cooler filter and pancake, get the mopar versions. Use ATF+4 or Amsoil universal. you can easily disconnect the lines at the external cooler for a cooler line flush.

If you have the NV242 select trac(rare behind the V8)takes ATF., if quadra trac, NV247 takes Mopar Fluid.

THe diffs take 75W-140 with the trailer tow in rear 80w-90 up front. If quadra drive both take 75w-140 syn. I use Amsoil. The quarda drive or trak lock on the earlier need the limited slip additive.

Coolant is the HOAT mopar orange. Steering uses PS FLuid, not ATF. I use Amsoil PSF or valvoline.

Go to a Jeep store and ask if they can run the VIN in their system and give you a print out of any work done on it, they usually will.

Jeeps Unlimited
http://www.jeepsunlimited.com/forums/index.php

This site has all the info including maintenance
http://www.wjjeeps.com/

 

[HawkeyeScott]

Good suggestions guys. Thanks a lot.

It's a Limited. White, FWIW.