# Help! 4WD not working on 1999 Jeep Grand Cherokee



## Middle River

Just bought this jeep yesterday - 1999 Jeep Grand Cherokee Limited, 147K on it. Went to park it in our driveway that only has a couple inches of snow currently ( more on the way ) and I'm stuck. Sure enough, only the rear driver's side wheel spins, in both the all time 4WD, and when put into the low 4WD. 

The jeep seems to drive just fine down the road, minus the 4WD not working - it very much drives like a rear wheel drive vehicle, not too good for the me in WI winter! But there are no funny noises, so i'm really looking for suggestions for my husband when he gets here tomorrow morning from ND on where/what he could start looking at??? 

Check engine light is on, only code it pulls however is for the speed sensor, could this have something to do with it? Really hopeing hubby can at least find out what the issue is before he leaves to go back to work in ND on Tuesday, as he only makes it back for a few days every month or so :smack

Thanks!


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## Allen W

Manual or automatic hubs?


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## Middle River

automatic? - the only options are 4-all-the time, N, or 4 Low. Thanks!


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## Bearfootfarm

I would suspect the hubs aren't locking.

I'm not sure if it is related to the speed sensor light


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## Energy Rebel

I'd definitely check out any problem with the speed sensor. The 4wd likely has to have a signal from it to tell it it's going slow enough to be engaged. Most vehicles will let you put it in 4wd if your not going too fast. Google some and check out the Jeep forums. I've found a lot of answers to problems that I had and some good fixit suggestions.

Here's one explanation.....

http://www.wjjeeps.com/speed_sensors.htm


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## crispin

read the OP - it is FULL-TIME 4 WHEEL DRIVE
there is no speed sensor to check.

It is a slip based system - personally I think it is going to be expensive to repair


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## Middle River

Ok, hubby made it home late last night and took a look. The transfer case appears normal, the shifting ect. Also the drive shaft and everything spins. There are no obvious problems or noises there.

Re-checked the check engine light - code P0720, output speed sensor. 

From what he sees something is not allowing the auto hubs to lock in, in all time 4wd and also not in 4 low? We googled and looked on some forums, and can't really find a good answer as we don't have any other noises/apparent problems??? He is wondering if this speed sensor could be causing the jeep not to engage 4wd? Or is there anything else you all can think of ?

Thanks!


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## alleyyooper

You bought it yesterday?If it was from a dealer take it back and have them fix it. 

If not the first place to look is the vacum system that engauges the 4x4 part. One part is on the front axel on the right side of the pig looking from the rear. A hose could be off there. Also If I remember right there were 3 systems in 99 for the 4x4. One was slecttrac is at one time could not be engauged till you were completly stopped< I think they redid it though at some point.

 Al


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## Bearfootfarm

> *read the OP* - it is FULL-TIME 4 WHEEL DRIVE
> there is *no speed sensor *to check.


Evidently there is a speed sensor



> Check engine light is on, only code it pulls however is for the *speed sensor*


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## crispin

Does anyone who has posted here understand what a FULL TIME 4 DRIVE SYSTEM does?

I will explain it as I doubt very much anyone does. I have currently a few 4 wheel drive trucks and a couple of full time 4 wheel drive trucks. They are VERY DIFFERENT systems. You do not ENGAGE a full time 4 wheel drive system. What happens is as the truck senses the rear wheels slipping (spinning) it sends power to the FRONT wheels AUTOMATICALLY. There is no lever, botton, or hub to engage. The car does it itself.

All car with computers (mostly) have speed sensors, it may or may not have anything to do with the lack of the full time 4 wheel drive working.

Bearfootfarm you should try to understand more instead of just trying to be 'right'


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## mightybooboo

Speed sensor is currently out on my VW,speak of the devils,a 2001 

What it does on my car is put it in limp mode,allowing only 2nd and 3rd gear to engage..Really nood to change it,fortunately its ext,but its a 3 inch engine drop sooo....

Anywho,yes,that speed sensor needs fixing,its important and may just be the cause,dont know for sure,but I do know,its needed and important.

Might also just be it read wheel slip and a simple reset and not related to the system.

Are you saying the system is purely mechanical?


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## Middle River

Update - changed the speed sensor, that didn't fix it. But it did take the check engine light off.

But now where to look next? I think he is going to investigate the vacuum system, but till he does he isn't sure if this jeep has one yet. 

Thanks for the tips so far, and any other ideas are more than welcome!


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## mightybooboo

If they didnt disclose 4wd didnt work you have a reasonable expectation to think it does.

I'd take it back,and if that didnt work you should win in small claims court.

Just saying 'as is' doesnt cover everything,though they like you to think it does.


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## poischis

On my cherokee(not grand) the front driveshaft always turn, although mine is a part time 4x4, not the full time like yours. The cause of your lack of 4x4 is probably the vacuum system, I'm pretty confident the Grands had that system too. so if the transfer case is fine, the driveshaft if turning, then your problem is in the front differential(vacuum, gears, etc.) Oh btw if you lift the front end you should be able to rotate one wheel and the other one should be turning opposite direction, meaning the gears are in proper order, leaving probably only the vacuum system to be wrong. The speed sensor is obviously not in cause, because they have a mechanical ''shift on the fly'' transfer case which allows you to shift in 4wd at any speed, as long as the rear wheel are not spinning. Hope this helps, -Poischis


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## Energy Rebel

Middle River said:


> Ok, hubby made it home late last night and took a look. The transfer case appears normal, the shifting ect. Also the drive shaft and everything spins. There are no obvious problems or noises there.
> 
> Re-checked the check engine light - code P0720, output speed sensor.
> 
> From what he sees something is not allowing the auto hubs to lock in, in all time 4wd and also not in 4 low? We googled and looked on some forums, and can't really find a good answer as we don't have any other noises/apparent problems??? He is wondering if this speed sensor could be causing the jeep not to engage 4wd? Or is there anything else you all can think of ?
> 
> Thanks!



Sounds like the same problem here.......

http://www.jeepforum.com/forum/f11/4wd-not-working-1163817/

Also found a few solutions that were suggested.
Check fluid level and also a generous dose of WD-40 to the hubs and linkage.
Did it work before?????


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## crispin

Energy Rebel said:


> Sounds like the same problem here.......
> 
> 
> Check fluid level and also a generous dose of WD-40 to the hubs and linkage.
> Did it work before?????


What HUBS and Linkage? It is full time 4 wheel drive.

It doesn't engage or disengage (bangs head against wall) It is FULL TIME 4 wheel drive.


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## Energy Rebel

Middle River said:


> Ok, hubby made it home late last night and took a look.* The transfer case appears normal, the shifting ect. Also the drive shaft and everything spins. *There are no obvious problems or noises there.
> 
> Re-checked the check engine light - code P0720, output speed sensor.
> 
> From what he sees something is not allowing the* auto hubs* to lock in, in all time 4wd and also not in 4 low? We googled and looked on some forums, and can't really find a good answer as we don't have any other noises/apparent problems??? He is wondering if this speed sensor could be causing the jeep not to engage 4wd? Or is there anything else you all can think of ?
> 
> Thanks!





crispin said:


> What HUBS and Linkage? It is full time 4 wheel drive.
> 
> It doesn't engage or disengage (bangs head against wall)



The link I posted had a picture of the mechanism, perhaps linkage is not the correct technical term.
Along with that was the forum itself that I've referred to for help with our Jeep Cherokee.
It may be automatic but obviously it has the ability to disengage,(albeit a mechanical malfunction) otherwise there wouldn't be a thread here.

I admit to not being an expert mechanic in every model of vehicle on the road, but I find the attempt to find a solution more constructive than being critical.

But to each, his own.


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## crispin

the problem lies in the transfer case. It is the device that once rear wheels start to slip it transfers power to the front wheels automatically.
The full time 4 wheel drive system in Grand Cherokees are known to be problematic.
I feel bad for the OP but it is most likely not going to be a simple or cheap repair.


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## crispin

Searching Google results says the typical cause for no power to front wheels is from the 
splines on your transfer case output shaft being stripped.

If you can't do the repair yourself I would guess this would cost over $1,000 to repair.

I have never seen a transfer case where the output shaft can be replaced without splitting open the case.

It would be easy to check this yourself. Unbolt the drive shaft from the front axle and slide it off the transfer case.
Some gear oil will pour out (you will need to replace the gear oil.


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## Bearfootfarm

> Bearfootfarm you should try to understand more instead of just trying to be 'right'


I understand you said there is "no speed sensor" when obviously there is since they replaced it :shrug:


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## alleyyooper

Jeeps full time system is called Quadratrac so you can google that.
Early ones did have failures with the chain.

 Al


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## alleyyooper

I can not say for sure since I never liked full time systems and never kept up on them. BUT! I think Jeep stopped useing the Quadratrac system in favor of the Slecttrac which allowed you to shut the 4x4 system down Like in the summer street driving yet allow full time 4x4 in the winter. Here are some Quradtrac links.

http://jubileejeeps.org/quadratrac/index.htm

http://www.jeep.com/en/4x4/how_systems_work/quadra_trac/

http://www.t-r-j.com/Auto/QT/quadratrac.htm

 Al


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## foxtrapper

As Crispin has been guiding you, this Jeep has the Quadra-Trac II system, and almost all the advice others have given you regarding your vehicle is wrong. When it comes to Jeeps, you *must* understand what type of system it is using. Your year Grand Cherokee came with the choice of three completely different 4wd systems for example.

I see in your posts you've been chasing red herrings, like hub lock problems (You do not have locking hubs). Read up and learn about what you have, not what you don't have. 

Put the Jeep up in the air, all four wheels off the ground. Put it in either 4wd mode, in neutral, engine off. Now turn the rear driveshaft. You will feel a lot of drag, and see one of the rear wheels spin. Do the same to the front. You should feel the same drag and see one of the wheels turn. If you don't see a front wheel turn, the problem is in the front differential. If you don't feel the heavy drag, the problem is in the transfer case.


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## Middle River

Ok, well we found the problem - and the seller completly lied. My hubby called them after we replaced the speed sensor, and said we have this problem still, as well as the problem that we bought a 4x4 vehicle that was advertised as 4x4, but is only 2wd - this whole time we are pretty much figuring we won't get anything from them, and taking it as a loss - plus the more we talk with the seller's the more shady they become. But had to at least try to act like adults. So finally my husband says we will bring it to the shop ( at the dealership ) and pay for them to find out the problem, then we will call back and let the seller know the findings, seller says fine, let me know and we can go from there.

The dealerships finds two things wrong - the viscus coupler ( I think thats the name?) looks to be shot, but also in the TC ( or differential, sorry I can recall exactly ) they opened it up to take a peek, and saw that the axles ( that the seller had replaced this fall ) that come into the TC/or diff, looked new, but also are not long enough to meet up with the gears in there - so their guess is the shop that did the work to the jeep put the wrong size axles in it - which they said could happen as there are a couple different sizes. Bottom line they ( the shop guys at the dealership ) said these people KNEW the 4wd was not working, as it hasn't/was impossible to work with those axles.

Only good news we got is they said everything else looks great, and most everything under there was new, and there is nothing effecting the driving of the jeep, but it is just a 2wd vehicle unless we want to put a lot of $ into it.

So I'm not sure what to do, we have pretty much called it a loss, but if there is any hope I need to find out about getting some $ back, or getting this jeep to work for us. 

So that means finding out IF we have a shot at court with these people - as they did lie, we have a few forms of proof ( slim-no chance i'm thinking ), I do know for sure these are some shady people and business owners ( they own a bar/grill/gas station) . 

Or maybe we can take a chance and bring the jeep into the shop they had all the work done and see if they did indeed put the wrong axles in and see if we could get a solution there ( slim-no chance i'm thinking as well ).

Or we can list it on CL for way less than we paid - stated and priced as a 2wd.

Or we can start another post here and find out if we can switch this jeep's stuff and make it a manual locking hubs jeep, and then keep it around for another driving vehicle/hunting rig. Hubby used to be a mechanic, and does all of our repairs...except now with our first nice/newer vehicles we bring them in for more major things - or the high tech things he hasn't delt with since technology has evolved so much. But he is more than capable of still handling many things with most vehicles, especially if they aren't needed for daily driving while he works on them.

So thats where we are at now. We often window shop at dealerships when we are in town with time to kill, and had time before our appt. at the shop, so stopped at a couple dealerships and "ooohed and ahhhhhed", then went to our appt. Well waiting there we looked at their vehicles and ended up buying on - a 2008 Jeep Grand Cherokee with 30K on it and warranty - so that was totally impulsive but we needed a vehicle in our current situation, and now don't have to worry. And now at least are only taking a money loss on the 99 jeep, and not a "oh crap, now we don't have a vehicle" loss. Oh, and they gave us a good deal, the best service and didn't charge us for the work on the 99 jeep.

Thanks again everybody for all your help and ideas!!!

Now, any ideas about turning it into a hunting rig buy changing the 4wd stuff up in the front? Or any suggestions on what we should do about the whole thing?

Sorry for the long post.


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## Middle River

I also ment to say, after we got the findings from the shop and called the seller back he just hung up on us - twice.


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## crispin

How come you didn't trade it in for the new Jeep?
I think you would have alot of work on order to change it out to a standard 4x4
I would sell it on CL personally


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## foxtrapper

Again, agree with Crispin, on all points.

Only thing I would consider doing is to return you 99 to working Quadratrac II. It'll cost you a shaft or two (drive or axle) and you'll likely be done. Not a complex job, nor a particularly expensive one if you do it yourself. 

Trying to remove a very good system (and the Quadratrac II is a darn good system) and replace it with a more conventional 4x4 system will be expensive, difficult and not work as well. But, if that's your dream, go for it.


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## Middle River

Didn't trade it in because we can most likely get more on CL for it, or even get more out of it just by driving it ourselves ( use ). Plus we weren't/aren't sure yet what our plan is with it.

Thanks for letting us know it would be easier to fix the current 4wd system rather than change it :+)

Now, I have no idea what it's worth on CL as 2wd :+(


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## mightybooboo

and the seller completely lied. My hubby called them after we replaced the speed sensor, and said we have this problem still, as well as the problem that we bought a 4x4 vehicle that was advertised as 4x4, but is only 2wd - Bottom line they ( the shop guys at the dealership ) said these people KNEW the 4wd was not working, 
-------------------------------------------------------
Sounds like you have a case to me,a non Lawyer.

It costs next to nothing to take them to small claims court.

Judges HATE cheaters and Liars. I would give it a shot.Mom bought a used car from a private party and it died on way home,she got her money back in small claims court.

Did you save the ad?Got paperwork on the problem from Dealer? I'd say its a good chance you will win,and I surely would at least give it a shot.Even if you just tell the Judge your story,he will determine who is cheating who.
===================================
Read this link.....
http://www.bcsalliance.com/autoloans08a.html

The most common type of implied warranty is the warranty of merchantability, which means simply that the seller promises that the product offered for sale will do what it is supposed to. That a car will run is an example of a warranty of merchantability. This promise applies to the basic functions of a car. It does not cover everything that could go wrong. For example, breakdowns and other problems after the sale don't prove the seller breached the warranty of merchantability. A breach occurs only if the buyer can prove that a defect existed at the time of sale. A problem that occurs after the sale may be the result of a defect that existed at the time of sale or not. As a result, a dealer's liability is judged case-by-case.


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