99 Trooper maint questions - 100K

I have an 99 trooper approaching 100k and wanted to get my act together on maint for the truck. I've changed oil every 3-4k, but not much else. It started consuming oil badly around 70K, as stated elsewhere in this forum, but I'm almost done with the www.auto-rx.com treatment and looks pretty good so far. I've had the rear diff oil changed a year ago and I changed the plugs around 60K. I also had a fan-clutch seize and had it replaced by the dealer, pretty expensive part. It runs really good, but I think I need to so some serious maintenance to keep it going.
While reading this forum, I've determined that the timingbelt, water pump and tensor pulley are about due. I've changed a timing belt on a 95 camery, and was wondering if this is a DIY job, or should I take it to the dealer?
I'll clean the EGR value this weekend. Should I replace the original O2 sensor also?
Just this week, I've noticed something like a 'bump' or 'slip' from the trans when just starting out from a stop. I'm guessing I may need a flush and filter. However, I understand that its a sealed system, and doesn't require changing... ever? If I do need to change it, is this best left to a flushing machine or a DIY job?
Last question, I read that the transfer case oil, front/rear axle oil should be changed. Is this an easy job, and how often should I be doing this going forward? I'll double check the owners manual, but I don't recall seeing all this stuff in it... glad I found this site!

-Mike

The slip in the tranny could be due to low fluid. They tranny fluid should be replaced every 30k.

If you have never done it. DO NOT have it flushed. I would take it to a place and have the pan dropped and the filter replaced and then they will replace the fluid that was in the pan (about 3.5qts of 9 in the system).

The front diffy oil should be changed every 30-50k.

The key things to keep it going is to have all new fresh fluids, and filters put in. Also, it sound like you haven't changed many of your fluids, so I would swap them all out.

And change that timeng belt (and other parts you mentioned) too.

A little money now will keep you troop'en for another 100k.

Just curious, why not flush the system? And does that mean never, or just until I run for awhile with a partial change?
Is dropping the pan and front diffy oil something I could just do myself? I read elsewhere you need two people to drop the pan.

-Mike

I wouldn't recommend the flush. A flush on a highmileage tranny, that has never had the fluid changed can cause 100k worth of gunk to free up while flushing (which could clog some narrow passageways), and it can cause the friction disks to start to slip too. It is a 2 person job? I would think the second person would hurt.

I think the key thing is that now you are at 100k you really should change the tranny filter out (located in the pan).

I the front diffy fluid change is a DIY thing (I have never done it; i'm 2wd) from what I understand. Hopefully someone will have some more answers to your questions.

Don't forget to change the power Steering fluid and the brake fluid too (if it is fluid change it).

You have 4 oxygen sensors not 1. They are usually pretty good about flashing a CEL when they start to go. Given this and the price you may want to wait until you get a light or notice your mpg dropping.

Like already noted putting fresh fluid in a neglected AT is asking for trouble. Can't say for sure what I would do in your situation.

The problem with doing a filter change and replacing some of the fluid is that any new fluid can still loosen particles and cause problems. This begs the question of how long you would go before doing another filter job. If you wait thousands of miles you could be doing some major damage.

Alternativley if you flush out all the old fluid you have the full potential to cause problems. Then again you could maybe do the flush. Fluid is cheap and it would rinse out a lot of junk. Within say 25 miles tops (yes I mean only 25 not 25,000 miles) or so you could drop the pan the do the filter and another flush. Still no guarantee of being problem free it just seems the more fluid you flush through the better, provided of course you quickly change the filter to get out the newly loosened junk. Still though no guarantee that some particles might loosen over the next several hundred/thousand? miles necessitating another filter job. Still though adding a flush at the start of the work just seems to me like a better way to get more junk out of the sytem.

Your best bet is no doubt to ask a good AT shop what they recommend.

Like already noted it is a good idea to change all your other fluids (e.g. brake, power steering, coolant). The transfer case and front diff are pull a fill plug, pull the drain plug and refill type jobs. The jobs shouldn't be that hard but if you don't have a pump, good catch pan, try to do it on a hot vehicle, don't remove the skid plate, put in the wrong fluid etc. you can make it hard

I'd get the truck up to temp, do 2-3 AT pan drain & fill cycles (drive maybe a few miles between drains). Drive normally for a week or so, see how your 4L30E behaves. Then do a pan drop & filter change. You are pretty freshened up by that point, but if you wanna do an ATF transfusion after that, it's up to you. Your driveline *thunk* is probably a driveshaft slip yoke that needs to be greased. Look for the rubber boots on your front/rear drive shafts. The slip yokes are under those. If there is no grease zerk, you have to remove the flange bolts, drop the shaft, seperate & grease. Replace your PCV valve with an OEM unit to keep crankcase pressure low. Aftermarket PCV many times dont fit right, or are not flow metered properly. I personally would wait on the t-belt & associated equipment R/R, until: 1) you hit 125K+ miles or so. 2) you water pump starts to weep. 3) the t-belt tensioner bites the dust. You must be a bobistheoilguy if you've used autorx? you are probably familiar with lube control & fuel power than? If you are still experiencing heavy oil usage, pull your spark plugs & pour LC right into the cylinders for an overnight soak to clean the ring packs. The next day, throw some large rags over the cam covers & bump the engine over a few times to blow the junk out of the cylinders. Throw the plugs back in & away you go! You may need to do another treatment or two. Dunno for sure. Oh.. and do an engine coolant drain/flush as well!

Travelman offers a good point, in that dont worry about your oxygen sensors unless you are getting a CEL from one of them. You have 4 on the truck @ about $50/ea.
G/luck
Joel

Rodeo2 -
I was worried about the thunk, so I stopped by a transmission shop that offers free analysis. They said the trans was fine, and fluid looked/smelled good. He said he thought the thud was the driveshaft, so your probably right. Manual says use MOS2 grease. I was looking at Autozone, and didn't see anything like that. What kind of grease can I use on the shaft? I thought the rubber boots where on the axel shafts, not the main drive shaft? Haven't looked that close yet..
When I fiirst encountered the oil problem, I had no clue what was up, so I went to the dealer. They claim they didn't have a clue either.. hmmm... so they just replaced the PCV and oil, and said come back in 1,000. A subsequent web search lead me to the auto-rx stuff. Just finishing the first phase.
I don't know about the lube-control and fuel power. What is that?
I had the same thought on the t-belt, just wait a little longer.

Thanks for the help! Mike

P.S. I found a local transmission shop that will do a trans service for $30. He says he's been doing trans for 27 years, and he does this service at cost to win customers.. I'm probably going to let him do it.

Mike, red crown is a good slip yoke grease (napa usually has it), as is a product used by ford (not sure what it's called), it's a thick blue silicone grease that works really well on their trucks (dealer item). If you are not going to clean out the old grease that's in there, Id stick with OEM or what the manual/dealer says. Check out http://www.lubecontrol.com/ for LC & FP info. There is tons of good info about the autoRx you've used and FP/LC @ www.bobistheoilguy.com.
G/luck
Joel

Lube on the slip yoke seemed to fix the problem.
Once last question, when changing the Trans filter, do I drain from the TOD box? Or are they seperate systems? If they are connected, can I just fill after I'm done from the TOD, or do I need to put some fluid directly in the pan before mounting?
-Thanks, Mike

The TOD case is completely separate from the AT.

You could put fluid in the pan before reattaching but why run the risk of sloshing it all over the garage floor and/or yourself? Also, even if you go this route you still have to add at least a quart of new fluid through the fill plug. Save yourself some trouble and put the pan up empty and then add the fluid through the fill hole. You then do the rest of the drill - car started, fluid warmed up, complete the refill, etc.

Keep asking such questions beforehand lest you have to do the job twice like was the case for the EGR.