1998 Jeep Grand Cherokee questions

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:mrgreen:



Very hard to help you with the 4WD question without knowing what year or model the Jeep is. Laredo is an option package, not the model. It's one of those things that helps so much.

As for the engine question goes, well same thing. Could be a V6 or an L6 depending on the year, either way it doesn't have a timing belt. Yes the chain, and gears, will need to be replaced. They are not however a maintenance item like a timing belt and their lifespan has alot to do with how the vehicle has been maintained and driven. Based on experience the timing set is good for 150-200k miles. Your results may vary.

posted by  vwhobo

I own the 6 cyc. auto Laredo. I bought it new a few years ago but I do not have an owners manual. This is my first suv and first 4wd. I have some stupid questions ;)

1.) Does this engine have a timing belt or chain? If chain, does it ever need to be replaced? If yes, in how many miles?

2.) I have 4, four wheel drive settings. 2wd, 4wd part time, 4wd full time, then 4wd low part time. I assume the difference between 4wd part time and 4wd full time is posi vs no. Is that correct? I certainly notice better traction in 4wd full time. I also have what appears to be the wheels grabbing when I make tight turns in any 4wd setting. She jumps around a bit when I am making turns while in 4wd. Is that normal? I test drove two before I purchased and assumed it was a function of 4wd.

Thanks!

--Matt

posted by  Matt

hate to be like..uumm..you but the years in the subject. gotta think before you post. :D :oops:

posted by  SuperJew

D'oh.

posted by  BavarianWheels

BUSTED!!! Yeah, I guess I gotta start reading the title before clicking on it. I just look for the yellow box and click.

Matt, please accept my apologies.

posted by  vwhobo

hehe

posted by  SuperJew

So let's try it again. You have a 4.0L L6 engine. Please see my previous post regarding timing set mileage expectations.

As for the 4WD questions, yes you can expect some "jumping around" on dry pavement. That's why you should only use the part-time 4WD on low traction surfaces (heavy snow, dirt, mud, etc). As for the full-time 4WD, the driveline has a viscous coupler and actually operates in 2WD until said coupler detects slippage in the front tires. At that time it couples so you have 4WD. Think of it a being 4WD on demand.

Now for the suck part. If you experience jumping while in FT4WD it most likely means the viscous coupler is going bad. The only way to fix it is to replace it. Not doing so will cause havoc with the rest of the drivetrain.

I hope I explained this in an understandable way. If you have any questions or need clarification, just ask.

posted by  vwhobo

See...he is a nice guy as I thought.

posted by  BavarianWheels

yeah BBCheck needs to see this

posted by  SuperJew

No, I'm an asshole and proud of it. ;)

posted by  vwhobo

Although I haven't actually seen mine...I am proud of its accomplishments.

posted by  BavarianWheels

Thanks for the reply.

I should probably ask my question differently. What is the difference between the Part Time 4WD settings and the FT 4WD setting?

I definitely have more traction (tested in snow on a hill) in Full Time 4WD compared to Part Time 4WD. I stopped my Grand Cherokee halfway up a hill covered with snow. In 2WD I could not go up - the rearend would just slip and fish tail. When I put it in Part Time 4WD I could make it up the hill but spinning a bit. When I did the same test with Full Time 4WD I could accelerate up the hill like I was on dry pavement. (It was awesome - I was then SOLD on the Jeep Grand Cherokee in terms of traction).

I assumed from that test - perhaps incorrectly - that the Full Time 4WD setting meant that I had posi 4 wheel drive - all four tires spinning at the same rate. I assumed that since I had less traction in Part Time 4WD that perhaps 1 front tire and 1 rear tire were spinning with that setting.

In terms of the coupler I don't recall if she jumps around in Full Time 4WD when making a tight turn....I will probably test that.

Lastly - what timing system does this vehicle have - chain or gears or belt? When should it be replaced?

Thanks

--Matt

posted by  Matt

Ok...It seems simple to me...but each person is different.

2wd is simply that 2wd - two wheels do the driving

4wd - 4 wheels do the driving

part-time - This vehicle obviously has some sensors that sense wheel slippage. In this mode, when on "flat" terrain the vehicle is in 2wd. If you venture onto a rougher road or steeper grade and the vehicles sensor sense wheel slippage, it automatically engages itself into 4wd until the sensors sense there is no need for 4wd.

Full-time - I would assume it is in 4wd as a physical constant. Regardless of terrain. Be it flat and smooth.

posted by  BavarianWheels

It's not that simple actually. Different vehicles have different drive characteristics of course. In my Jeep 2WD actually means 1 wheel providing power (rear right). Reading my test scenario you see that part time 4wd behaves differently than full time 4wd under identicle circumstances and terrain.

I appreciate the help.

--Matt

posted by  Matt

Interesting. So according to Jeep (is that made by GM?) 2WD actually means 1WD (with the qualifier of "Right-Rear")

Kudos to Jeep for that one.

Could it be, Matt...that when this right-rear tire was the only one spinning or making "power" - was when the left-rear was stuck?

posted by  BavarianWheels

Ha ha - hey - it's no BMW but the Jeep would be my vehicle of choice for getting around in a foot of snow! I have never seen a vehicle that could handle conditions like the Jeep.

OK back to task.....

If you are on dry pavement and stomp the gas - only the right rear tire will be spinning - definitely not posi 2WD. Based on my experience with the Grand Cherokee in Full Time 4WD it appears to be posi 4WD.

This is partly why I'm here trying to determine the exact specifications from another GC owner or someone familiar with them. I should go online and spend the $20 to buy the owners manual.

--Matt

posted by  Matt

Agreed. But when I do need to travel in 12"s of snow, I rent a capable vehicle. I would never actually buy American.

posted by  BavarianWheels

dont u like never get snow in SoCal? u see you should all give us youre SUVs because we always get like a foot of snow every year.

posted by  SuperJew

Some areas recently received the mother load hailstorm last week in the L.A. area. It was deep enough to render vehicles undriveable. But other than that...only the gang-banger types sport the fixed up SUV's we "normal" peeps call "pimp-mobiles" or "ghetto machines"

Drive about an hour east and into the mountains...and voila...snow!!

posted by  BavarianWheels

Alrighty then, this is where I get to say read the post I've already answered the question. In my very first reply to your thread I answered the timing chain question, in my second reply I refered you back to the answer. Please read it.

As you have found MOST of the time 2WD means 1WD, and 4WD means 2WD. That is unless the drive axle has some type of a limited slip function. As for the different drive ranges I though that was pretty well covered. Let me make this as simple as possible.

2WD = powerflow to rear axle only
4WD/high or low range = powerflow to both axles, viscous coupling at transfer case locked
FT4WD = transfer case engaged, viscous coupling routing power to rear axle UNTIL it senses tire slippage, then routes power to front axle also as needed to eliminate slippage, as I said essentially 4WD on demand

I seriously doubt you will have better traction in FT4WD than PT4WD. Remember in part time the viscous coupler is always locked so you always have power to both axles.

posted by  vwhobo

Ha ha ha yes, the questions are very simple, as our your answers. There is not one single hint of confusion or misunderstanding to read your replies. What I'm looking for is a precise answer from someone who owns the same vehicle or could tell me in 5 seconds from the owners manual.

Obviously the damage that can come from timing failure (bent valves) is catastropic and serious. I need to determine the recommended maintenance for the timing system - the book would give a precise mileage to replace or have inspected, etc. I am fully aware of the purpose of the coupler in the 4wd system - I need to know how the different 4wd settings work as a point of fact not a summary of similar vehicles.

I do appreciate your answers. The concepts are very simple - I continue to post because I am looking for specific facts.

--Matt

posted by  Matt

I am not summarizing facts from similar vehicles, I am giving you specific facts for your vehicle. There is no precise replacement interval for the timing chain or gears, nor will you do any damage to the valvetrain as your's is not an interference engine. The mileage I quoted is based on over 30 years experience and approximately 200 cars per week going through my shops, a percentage of which have that engine.

As for the 4WD system, if you understand my explanation as you claim to do, you probably have a better understandiing than if you read the owners manual. If you only wanted info quoted directly from the owners manual you should have stated that in your first post. That would have saved everybody time and effort.

And you guys (you know who you are) wonder why I get so frustrated trying to help people. :rolleyes:

posted by  vwhobo

I did not know you were replying based on specific knowledge. My questions are answered then, thank you for the help. I was put off by your replies that were a bit condescending. It appeared you thought your replies were over my head.

I have only experienced engines that are damaged by the failure of a timing belt so I assumed the same potential existed with my Jeep. I can't explain why I appear to have more traction in Full Time 4WD. I conducted the test I mentioned several times. Halfway up hill in part time 4WD with 1 foot of snow - could get up the hill but slowly. Full time 4WD and I could literally accelerate up the hill. The traction difference was immediately obvious.

Once again, thanks, my questions are answered.

--Matt

posted by  Matt

I was quite confused myself as to what exactly Matt wanted as it seemed his question was answered at least twice!

::understands vwhobo::

posted by  BavarianWheels

I thought I was the only one. ;)

posted by  vwhobo

yeah i was kinda confused at what Matt was talking about/wanting. oh, maybe its cuz i didnt feel like reading everything. :D

posted by  SuperJew

no timing belt, dont worry about it, the four wheel drive system you are describing is quadratrac, the low lock and high lock are for off road use only, they lock all four wheels together and will will cause the transfer case to self destruct on pavement where the tires cant slip.

posted by  crash8168

Thank you for confirming what was answered two weeks ago.

posted by  vwhobo

Matt, your Jeep only came with three optional engines for 1998......the standard was the INLINE 6 cylinder 4.0 Liter workhorse, the optional 5.2L Chrysler 318 Cubic Inch V-8 OR if you purchased one of those Limited Edition "5.9 Limited's" ONLY for the 98 production year, it came with "kind of the Dodge R/T package" which is Chrysler's 5.9 Liter 360 Cubic Inch V-8. You have the 4.0 Liter and it was not available as a V-6 configuration. As VWHOBO stated earlier, it is NOT an interference engine. There are two types of engines out there, interference and NON-interference. The 4.0 I-6 is NON-interference so this translates into if the timing chain breaks, valves and pistons don't get screwed up, if it were interference, you're quite possibly screwed.

I have the 4.0 litre engine in my 1995 Cherokee Sport five speed and it is a VERY strong and durable motor that will run way on into high mileage as long as it has been maintained. I worked for Chrysler for two years as a tech for them, and I can tell you that timing chains in those engines last a long time and rarely cause any issues. I have 133K on my Jeep and there are no signs of poor engine performance hinting any stretching of the chain or anything to indicate problems with my timing changing. I have always taken care of it though and done all maintainence, actually it is in mint condition. I would not sweat over the chain in that engine, you're likely to have no problems. naturally everything wears in time, but with it being a 98, I can't forsee any issues yet.

posted by  cmeseadoin

It's Me again!!! I read another article on this page about quadatrac, somebody said you don't want to leave it in lock or it will destroy the transfer case. I looked on my quadratrac and on the shifter it only has 4 all time neutral and 4 low. I put it in neutral, and it won't move. It has to be in either 4 all time or low. Is the vicious coupler that vwhobo talks about, the 1 that bolts to the transfer case? thanx again,,, ED :banghead:

posted by  eds426

I think the Jeeps or recent vintage are currently made by Diamler-Chrysler

posted by  tbaxleyjr

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