Isuzu Owners Maintenance and Repair

gpm5

My 684s had cracks between the tread blocks. Also, a couple of the tread blocks were cracking along the edge so that you could sort of pry them up slightly. Worse up front. I noticed a rodeo in the parking lot here just yesterday with good tread but also with cracks that were even worse. They were split from in between the tread block and the crack turned the corner and went down the sidewall. That looked very scary. The Bstone/Firestone people blamed the sun, the salt, and everything else on the planet. The problem is all tires face this, but few show this cracking after less than 2 years. I was PO'd with them and their explanation and decided to trash the whole lot including the spare. I will never buy their product again. It probably won't matter since the law suits are likely to bankrupt that company. I think they have been told not to deal with replacements on anything that they don't have too, no matter what the tire looks like.

Oil filters: I noticed the Mobile 1 filter had steel burrs around the threads. I did not buy that brand. I also didn't like the round instead of flat O-ring on the M1 filter. I got the Purolator, but I got the next one under Pure 1. I could not find the Pure 1 in stock anywhere when I looked. I've read that the Pure 1 might have so much filter material that it could inhibit the oil flow--don't know if this is true.

The Isuzu service shop told me about $350 to replace tranny fluid and diff fluids. I may go with that. They recommended 30k. Probably 35k is fine.

basketballkid

I just got back from my first visit to the a dealer since I purchased my 99 trooper.

tire rotation - dealer advised me not to rotate them. I told them they hadn't been rotated in 20K miles. He said they would "roar" if I changed them now. So I decided not to. I guess I'll get getting those 265's that much sooner.

rear seat cupholder had fallen off - he had to order some clips. Couldn't fix it yet.

jumpy idle (0-1000 rpm w/warm start) - told me I had a vacuum leak. He replaced the gaskets on the intake manifold. So far so good.

CE light - the new gaskets seem to have put the light out too.

Brakes modulating - He said my rear rotors were "rotting." Will replace under warantee but needed to order the parts.

Not everything has been fixed yet, but looks like my net cost will be $0.00.

He told me for the cost of the pads (my cost) I might want to consider having the rear brakes done while they have everything apart. He said the pads would be $70. I have 27K miles. Sound like a good idea? He said a brake job (rear only) down the road would be about $160. Is this too much to pay?

Phil

paisan

Is a bit steep for pads, but not outrageous, considering they are OEM, Pep boys would probably be like $40 for rears. As for $160 that is about standard for brake jobs nowdays. I am not mechanically inclined at all, but on disc brake cars, I do all my own brake pads since it's about 1/2-45min tops to do it yourself (2 bolts get unbolted and release the pads, snap in new ones, use a big clamp to push in the pistons of the calipers, and you are pretty much done)

-mike

randers3

I put Mobil Synthetic in my rear diff at 10,000 and again at 25,000. Both times I had to add two
bottles (not sure of amount in each bottle)of GL5 Modifier. Instructions call for just one bottle of GL-5 but after changing to synthetic I developed quite a bit of chatter in the rear end. Isuzu mechanic told me to add another bottle of modifier. This took care of problem. On another note I always have used Mobil 1 filters as they have synthetic filter material and filter out the smallest micron contaminates of all filters.

cmuniz

The erratic idle may also be caused by the pcm (computer).There is a tech bulletin out that covers that. If it starts to do it again in warm weather I would take it back to the dealer and have them re-program the pcm. Just had mine done and it seems to have fixed the problem. On my '96 Trooper I had my brakes done at 35,000 miles since I live in the mountains and use them a lot. The backs were in much worse shape than the fronts, which is the opposite of what I would have expected. Based on my experience and since they are going to take them apart anyway, I would also have the pads replaced by the dealer. If you do primarily freeway driving, it might be early to have it done, but it will cost much more to do it later.

paisan

Yep I noticed the same thing in my '97 rodeo, first set of rears went 50K, and the fronts went 65K. And that was in mostly city driving.

-mike

beer47

Randers3,
Do you do a lot of off-road stuff to require changing diffy fluid at 10k & 25K. It seems a little frequent but maybe your a ranger at Yellowstone or something. It seems a bit much if your just going around town or freeway. Do you drive around in TOD all the time? I guess on the positive side you are preventing possible problems with these changes. Also, have you repacked the bearings yet? I am interested when everyone is planning on doing that; at what interval. Safe driving to all...

breakor

I did my wheel bearings at little over 30k right after we bought a used Trooper. The grease still looked ok to me. That being said I plan on doing the next service at maybe a little under 30k more miles as I suspect we will do much more off-roading than the prior owners.

The 10k diff fluid change sounds early to me too. Then again some people want to make the conversion to synthetics ASAP. IIRC the next service is then supposed to be 15k later (and every 30k after that) so the 25k service then sounds correct to me.

FWIW when I changed the diff fluids at the same time as the bearing service, the front looked to be in great shape. The rear looked a little dirty but still appeared to be in very serviceable condition. If I believe the prior owners they had the 15k service done. In which case the fluid did look quite dirty for only having 15k miles on it. This would support the need for doing a 15 and 30k service. However, it is entirely possible that the prior owners did not have the 15k service done. If this is the case then waiting to do the first change at 30k would appear to be fine unless of course the warranty requires it earlier.

bluedevils

$350 to change those fluids sounds ridiculous.

At most quick lube places around here (Detroit), an ATF service (won't get all the old fluid out) is $35-40. The total replacement method with that fancy machine is $50-60. I see "4x4 specials" for changing t-case and both differentials for $45-50. That's well under $100 for ATF and differentials from quick lube joints. Granted, I expect that a dealer should charge more (they SHOULD know more about your vehicle) but 3-4 times the cost is way too much.

bluedevils

I've heard others mention that the Pure One may be too restrictive in some applications, but overall people think it's a great filter and a great buy at $5 (typical price around here).

The Mobil1 filter is widely regarded to be one of the 2-3 best available, but I can't justify the price tag-- at 10 bucks, it's double the Pure One and more than double an Isuzu brand from St. Charles ($3.50 on sale, $4.xx regular).

BTW, I checked an extra Isuzu filter in my garage and it says "Made in USA" and "FILTECH INC." on it. I don't know anything about Filtech or what other manufacturers/brands of filters that they make.

I'll probably stick with the Isuzu filter for now, unless some folks come forward with a Trooper-specific recommendation for the Pure One or something else.

bluedevils

Trooper brakes are well-known to last VERY high mileage with non-extreme use. I've heard several newer (92+) Trooper owners quote 60k, 70k, 80k, or more on a set of pads. Our '98 Trooper is at 51k miles and the brakes seem as smooth and responsive as when we got the truck 2 years ago (@ 7k miles).

I don't know what it is about the Trooper's brakes that explains the longevity - is it the pads specifically?

$70 seems okay, but maybe your dealer can tell you how worn the pads are. I wouldn't spend any money to replace a set of pads with, for example, 50-75% of remaining useful life.

$160 for a "brake job" also sounds reasonable, especially from a dealer. Not sure exactly what would be included in such a job-- rotors, pads, bleed the system, etc.

Nice to hear that some of your minor problems are being resolved.

bluedevils

Is the GL5 modifier an Isuzu product, a Mobil1 product, or somebody else's? What is the cost of a bottle, and how much fluid is in the bottle?

I, too, am curious to know why you changed the diffy fluids twice in the first 25k miles. Maybe I'm clueless, but our Trooper is at 51k miles and I'm not in a rush to change the diffy fluid.

paisan

I'm planning on doing the T-case, Tranny, and diffy's @ 30K intervals. Also $5 extra for a filter on a $33K vehicle IMHO isn't too much extra to pay for a superior filter.

-mike

bluedevils

I was catching up on the current General Isuzu Discussion over there and had gotten within 50 posts of the one you pointed me to!

After reading the thread, I think I'm almost ready to do the diffy fluid change myself.

I really need to spring for the factory workshop manual. Maybe for Christmas...

bluedevils

Yes, it seems to be a great filter, maybe the best. However, there seem to be some excellent filters that do an excellent job, for $5 (Pure One) or even less (Isuzu OEM, made by Filtech). I doubt the Mobil 1 filter provides any incremental benefit for the average driver.

armtdm

Well, I converted to syntheitc upon purchase of son's Rodeo which was 57,000 miles. I used a Mobil 1 filter (did not have time to get to my Amsoil supplier) Changed it at 3000 with analysis as I was concerned about cleaning up the engine. Analysis was great. So, now have 6000 on the Amsoil using the Amsoil SDF 36 filter which is about 2 inches longer then the OEM or the Mobil 1. Will change at 7500 and analysis again. If good I will go to a 12,000 interval oil change with a filter at 6000. I am going to use Amsoil filter but the OEM size, the longer one on there now is just too close to the hoses for my comfort but seems to work fine. This engine had three seepages upon purchase, still there, one looks like a valve cover the other is the oil pan and rear seal (2wd) However, oil usage in total has been about half a quart over the 6000 miles this time.

Synthetic ATF was also put oin at 57,000. This 2 WD has one grease fitting on the drive shaft between the two universal joints. I lubricate it but neve see anything come out. Any idea where the grease is going or what it is lubricating????

gpm5

Yes, it does seem high. They do a few other things like check the engine tuning, but still that is high.

gpm5

I'm not sure. The ones I looked at had metal filings in them from where the thread was machined. That can't be good for the engine if one gets inside. Another one had rust on the metal near the O-ring. I would pay $10 for a good filter but I'm not convinced that the M1 is good. It may even be bad (i.e metal filings in your engine).

beer47

I checked the manual and the chart said that A/T fluid is good till 100k. Did I read that right? The TOD and diffy fluids were more often. Can some one check me on this? This was/is a 2000 trooper manual.

paisan

The 2000 trooper manual, is anything from 20K or lifetime, depending on how you look at it. The 20K is under severe conditions, and the lifetime is under non-severe. I'm doing it ever 30K, as mine is semi-severe.

-mike

bluedevils

The owner's manual for my truck ('98 Trooper) states every 30k miles for A/T fluid change for severe schedule. The manual does not state an interval for changing the A/T fluid under "normal" conditions.

I'm planning on doing the A/T fluid between 50k and 60k miles on our Trooper.

paisan

Don't forget in 2000 they changed over to the "Grade Logic Transmission" also in 01 the rear end went from a Dana XX to the Isuzu 12 bolt rear end.

-mike

bluedevils

Thanks for the info on your son's Rodeo and your oil/filter plans.

Question: How long would you feel comfortable running a Pure One filter or the Isuzu OEM filter (I'm assuming it's a very good 'standard/non-synthetic media' filter) with Mobil1 5W-30?

I was planning a 5-6k change interval for both oil and filter. However, my Trooper consume about 1 quart every 2000-2500 miles, so at 5-6k miles much of the oil is not 5-6k miles old.

I'm open to your recommendations (e.g. 12k oil interval and 6k filter, as you're doing)...

BTW, I'd love to help answer your question about where the grease is going, but as soon as you mention driveshafts and universal joints you are way over my head!

gpm5

I would never go 12k on an oil change even if 50% of it is replenished by 6k and 50% again by 12k. The contaminants from blow by will be present even with the oil consumption. I would say 5-6k on an oil change & filter change.

bluedevils

I can't imagine myself ever doing that either, but you should hear some of these guys on the synthetic oil topic in the Maint/Repair forum. They seem pretty knowledgeable, and several of them are doing 10k+ oil intervals (usually with a filter change halfway in).

paisan

I do 5K-7500K oil changes even on synthetic. 10K oil changes will rear their ugly head when they blow an engine and the warranty company asks for reciepts of oil changes. At least at 7500 you are within spec for the auto-maker even on dino oil technically. I figure I drive hard so 7500 on synthetic is about equal to 3K on dino.

-mike

armtdm

Actually, on one of my other cars I use Pure Ones and switch at six months. Excellent filter, oil analysis fine

As to the contaminants that someone mentioned at 12,000 mile intervals well, oil analysis would pick that up and over the nine years of using syntehtics I have not seen abnormal wear or contaminants.

I know it is very hard to believe, it took me years of oil analysis to feel comfortable with extended drains but the stuff just does not wear out, (nor does it become contaminated) it lubricates as well at 12,000 miles as petroleum does at 3000.

However, to each his own, you have to comfortable with what you do.

bluedevils

armtdm - You're basically changing out the Pure One filter around 6 months, which equates to approx 6k miles on that vehicle? Does that mean you wouldn't really trust the filter for much more than that mileage?

central

Armtdm's often mentioned yet never defined "oil analyis" to the contrary, synthetic oil does wear out and it does get contaminated. This is specifically explained on the myths section of the Mobil 1 site http://www.mobil1.com/index.jsp

But like he said to each his own. Just do your own research and make up your own mind.

bluedevils

Gear oil
In the last 2 days, I've been to 3 major retailers' automotive sections (Wal-Mart, Target, and Meijer) and 2 parts stores (Murray's and Auto Zone). Gear oil has been hard to come by. Perhaps I need to seek out a specialty parts shop that stocks for commercial trucks, etc...

I found Mobil1 synthetic gear oil at Auto Zone ($6.99/quart), but only in 75W90 weight. I presume that 75W90 is fine instead of 80W90, since Mobil does not offer 80W90 (75W90 is the only one listed on their web site)?

One Wal-Mart had 80W90 Pennzoil synthetic ($6.97/qt) but I'd rather go with Mobil1.

ATF
I'm having a hard time justifying synthetic ATF for my 98 Trooper. 9.1 qts x $5 = a lot, vs. $13 a case for 'regular' Mobil ATF at local Costco Wholesale. I'll probably put synthetic in the TOD next time I change it, already running Mobil1 in the engine, and planning on synth in the diffys. Somebody convince me to spring for the synth in the tranny...

Isuzu limited slip additive
Ordered 2 bottles of the LS additive today from Merlin at St. Charles Auto. List $6.53, St. Charles' price (15% off) $5.55 each. Total $11.10 to my door.

Question: Merlin wasn't sure whether the LS additive goes in the rear diffy or both front and rear (I'm talking 92+ Troopers, specifically for my '98). I don't remember exactly what owners manual says but I think it implies rear diffy only. Can anyone clarify?

paisan

Is that enough reason?

i want to gofully synthetic. The mobil 1 is running well in the engine.

-mike

randers3

I use GM GL-5 Friction modifier for the LSD. This is the same fluid that my Isuzu dealership uses. Its a 2 oz bottle for $6.95. Outrageous, but thats the going price. In response to why the change at 10,000 and 25,000 miles, I went to all Mobil Synthetics at 10,000 miles. Tranny, front and rear diff, TOD, and oil. Changed rear diff again at 25,000 miles, which was a 15,000 mile difference from 10,000 as suggested in owners manual. Had wheel bearings repacked at 35,000 miles. Local dealership charged $125.00. Wanted to do myself but Trooper is somewhat different that standard wheel bearing repack and I got nervous and took it to dealer.

central

I've noticed that speed shops and off-road shops are very good sources for synthetic fluids, at least for the Amsoil and Redline brands

As to the AT, think about how complicated and expensive that unit is. Then remember how much gear changing you do and how much load it is under every day. Also remember that once filled you will likely not touch the fluid for maybe a couple of years and 30k miles. Seems to me this should also get the first rate treatment.

As to the LSD modifier, it only goes in the rear as only the rear has the factory limited slip.

Also, you might think about synthetic for the easy to overlook shift-on-the-fly unit (that little gear box thingy on the drivers side of the front axle). It takes very little gear oil and once refilled should be good for a long, long time. (IIRC it doesn't have a recommended change frequency just routine level checks.)

armtdm

Oil analysis for me is taking a sample of the oil before I drain it via a syphon from the dipstick tube. Sent to a lab for analysis where I get back all of the different metals in the oil as a parts per million number. this is trend analysis really, over a period of time you can see what the wear metals are doing and if you need to change oil sooner or suspect a problem. It also gives me the % of solids in the oil (volume) the % of fuel and viscocity. Also given are the chemicals in the oil used as additives and can also detect if coolant seeping in etc.

Comes back with an opinion as to whether oil is suitable for continued use.

Yea, synthetic does wear out, I meant that over 10-15000 miles it really does not show the contamination that a dino oil would. My cut off is around 12,000 as that is where my silicon level begins to get into the unacceptable ranges.

paisan

I wonder if the cost of analysis is worth it, or if it's cheaper to just replace it ever 3-5K?

-mike

bluedevils

Those sorts of battles/discussions have been waged in the Maint/Repair forum (synthetic oil topic) for a LONG time.

bluedevils

I thought the front diffy was not a limited slip but wasn't sure. Thanks for confirming.

I've been leaning toward full synthetic for the trans. I'll probably bite the bullet and go with Mobil1 for $5/quart. It probably is worth the extra money vs. petrol-based ATF.

paisan

No worms here

I'm considering actually putting in an Isuzu 10-bolt corporate front LSD in my trooper. That would be sweet And you can buy them new from Isuzu (need to order the rear end to an Impulse)

-mike

sdc2

You know, I have been wondering about that...wouldn't a limited slip diff in the front try to activate every time you go around a tight corner where the wheels are turning significantly different speeds? Or are the wheels turning too slowly to engage the plates in the diff in this scenario?

That said, if you do it I would be interested to hear how it goes, the $ and sweat involved, etc. C'mon, Mike, be the trailblazer (aka guinea pig)! :-)

paisan

Well I *am* a Guinea

I know of a guy who did it on a pre-92 Trooper, but not sure how it would work with TOD.

-mike

sdc2

Off the top of my head I can't see that TOD would be affected by a front LSD...

paisan

I think the guy who did the install has un-locking hubs, so that the LSD unit doesn't even turn when he's on dry pavement. I'll have to ask around and see what they say.

-mike

ilit

On the 99 Trooper, the front differential doesn't have LSD but the rear one does, thus the rear differential needs the additive. Anyway, the additive wouldn't harm the front differential if it doesn't have LSD feature.

central

I am glad to hear that you are getting what sounds to be a very comprehensive analysis.

I am somewhat surprised that the Si level sets your change frequency. You must really live in a dusty area (synthetics don't need much of the way of Si based antifoams do they?). I would have thought the viscosity or the acid/base tests would have been the determining factors. Also, make sure you understand the viscosity test as you can get deceptive numbers. By that I mean the tendency of the oil to thicken due to oxidation over time can be masked by the opposite tendency to thin as the longchain polymer additives shear and cause the oil to thin. Consequently, you can have a oil which tests "okay" but only over a very narrow range. If they only do 1 low temperature test they can miss this. Or, if they fail to ask you which oil, brand and grade, you are using they can also fail to detect how much degradation has taken place. It doesn't sound like your lab is missing this but it wouldn't hurt to check.

armtdm

Part of the problem with analysis and labs is that some values they consider absolute and should not be exceeded regardless of mileage and others variable with mileage. For example, wear metals should be variable, 20ppm of iron at 5000 miles would also be fine at 40ppm at 10,000 miles. However, fuel as a % of volume is an absolute and once it exceeds their cutoff point the recommendation is to change oil, as is total solids as a % of volume, water also. Silicon is a problem, analysis cannot differentiate between silicon used in gasket material, safe, silicon used as an additive, safe and dirt. Also, Amsoil has about 10-15 ppm of silicon in the oil out of the container so my lab cuts off the oil good recommendation at around 32 ppm of silicon reagardless of mileage so this makes the decision somewhat vague as to changing oil. Is the 32 including what they know is used as an additive etc.

Basically, suggestion I have used is that if the iron ppm are okay don't worry about silicon level because if dirt were getting into the oil the iron content would be way up there due to wear.

On son's Rodeo purchased at 57,000 miles used, first change was at 3000 miles, analysis great, next will be at 7,500 and depending on results will go to 12,000 after that.

fathead

I need help w/changing the fluid in my front differential in my 99 Trooper S. I've changed rear gear fluid before but this is my first 4wd, so first front diff change. The only plug I've found is in the front of the diff, and appears too high up to drain. Anyone got a clue for someone who is temporarily clueless?

Thanks in advance,
Fathead

edk8

I own a 92 Trooper LS with about 150k miles on it. It has been very reliable but lately I have been experiencing a transmission problem. The Check Transmission light will start to flash and the vehicle seem to lose power. I has happened on three separate occasions and each time I will park the car and turn off the engine. I start the engine a few minutes later and its fine and dandy as if nothing happened and will run for 2-3 months with no incident. The first time, I took it to my local Isuzu dealer to have the transmission diagnosed. The dealer told me that the computer diagnosis showed a code 12 or 14, I can't remember exactly, meaning the there was no problem detected. The next time, I brought it to a transmission shop and I was told there was not problem detected. It happened again last night and I'm at a loss on what to do. The tranny shifts smoothly and otherwise the car is in great shape, but I hate for the tranny to give out while I'm on the freeway.

Has any of you experience the same problem? Any idea what may be wrong? I'm willing to spend money to have the problem repaired for my own peace of mind, but I kept being told there is no problem.

fathead

Sorry, I just looked back a few days and found that ref to the ITOG post on this topic (front diff fluid change). Time to get to work!

Thanks,
Fathead

bluedevils

I thought someone had mentioned that the Pure One filter that's about 2" longer than the standard size filter for newer Troopers was PL24458. I did not see this part # at my local store, but I saw PL24457 which appears (externally) to be the same as the standard-size Pure One filter for the Trooper, except longer. Can anyone clarify? My local store (Meijer) has a $3 mail-in rebate right now when you buy 2 Pure One oil filters.

bluedevils

I just called Mobil 1's technical 800# (800.662.4525). The guy on the phone said that the Mobil 1 synthetic gear lubricant (75W90) will work fine in my 98 Trooper's front and rear differentials. My owners manual specifies 75W90 in the front diffy but 80W90 in the rear. The Mobil1 guy said their stuff will do just fine in the rear.