99 Jeep Drive Line

A little story for you guys. Ain't over yet.

I will start from the beginning.

We purchased this 1999 Jeep Cherokee Laredo Limited (always 4WD, no 2WD selection) used a little less than a year ago.

Shortly after, it started to made a lot of weird noises. Was drive line problems. Spent well over a thousand bucks to get it fixed at a drive line shop in Sparks, NV. All the drive line stuff was replaced. The shop was This one.

They have a one year warranty which is still good for a couple of months.

A couple of days ago, Tom and I drove our 1999 jeep Cherokee Laredo Limited from Reno to here in South San Francisco. Since we purchased this Jeep, we probably put less than a thousand miles on it (I own 11 motor vehicles , which are kept at any of my three homes--and so it takes time to get a lot of miles on any of them).

At around 70 MPH on the way here to SSF, CA from Reno, NV, it seemed like I got a flat around 50 miles east of here. Vibrations much like a flat tire. Stopped and checked. Tires were all okay, but the noise still there when it was driven. Continued driving the last 60 miles or so with the noise.

It seemed the noise was coming from the transfer case, which it was.

So today, we took this Jeep to a local tranny place to see exactly what the problem is.

They put the Jeep on a rack while we were there. The mechanic started the engine and put it in gear while on the rack and heard the same noise. Then he removed the front drive shaft from the transfer case. Inside the bell cover on the shaft, the gear was broken.

Okay, but why it was broken was the more interesting part.

There was NEVER a drop of grease in there. The seal was good, so no grease melted or leaked out. Seems like the shop forgot the grease. As dry and clean as could be.

I will call the drive line shop in Reno tomorrow and see if I can get them to ship a new front shaft to the tranny shop here in SSF.

I wonder what I should expect? I will probably have to pay for the shipping and labor or whatever. Anyway, what is the most likely outcome that I can expect tomorrow when I call the drive line shop in Sparks, NV?

-Don- SSF, CA

Start here

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Mission Statement

Our goal is to provide our customers with the best, the best services and the best products. We continue to drive forward with our dedication.

Quoted : Tom Hauptman, Owner

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Just gently tell him he needs to push forward a bit harder. ;-)

Oh; I almost forgot.
If you can't recover every microscopic piece of that broken gear, then one remaining microscopic piece may migrate into something else, like a bearing, and do even more damage.
An astute shop owner might prefer to ship you an entire transfer case, not just part of one, for that reason.
Do fill the new one with the specified lube, and put your own finger in to make absolutely sure the lube is there.

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We are committed to providing our customers with the best products on the market, as well as excellent support. We live by the following:

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• To produce high quality components that are useful, powerful and built to last
• To provide professional service that always meets our high standard of excellence. On Time!
• To share our experience with all who need help

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In the event of any obfuscation I would mention that you eagerly await their professional service (Bullet 2) and, of course, will be willing to share your experience with all who might benefit from your experience in line with Bullet 3.

Ken.

i just called the drive line place in Sparks, NV. They seemed very cooperative. They are going to call the transmission place here and send them a new front driveshaft. Looks like they will pay to ship it, but I will have to pay the labor, which in this case, costs less than the shaft.

I just hope there was no damage to the transfer case.

BTW, they claim it was greased, but it gets so hot it melts to the point it cannot be seen. I assume it is possible as I know from driveshaft motorcycles, the grease used on splines dries very quickly and no longer looks like grease, but still does its job as well in the dry looking state. I know about this because almost every motorcycle I ever owned had / has a drive shaft, including the three out of the four I now own. See here.

"The first time you remove your rear tire, you will likely find that the factory grease has dried out completely and solidified into something which does not even remotely resemble a lubricant. Actually, if it's a good Moly grease, it's still doing its job in this form, but it's not a pretty sight."

Perhaps they use a similar "paste" on these gears. But if that's the case, I would think the guy at the tranny shop here would know such. Or perhaps they incorrectly use the wrong type of grease at both places, just like Honda shops mentioned in the article.

Or should it be a regular type of grease on the shaft in the Jeep's transfer case?

Either way, isn't it rather unusual for a new front drive shaft gear to break in less than a year? Seems something must have been wrong to begin with.

-Don- SSF, CA

I just talked with the guy at the tranny shop here. The shop in Sparks, NV, will send the shaft overnight.

While the Jeep is in the shop, I am having him do a flush of the tranny as well as change the gear oil in the transfer case.

Looks like the gear oil in the front and rear differential has recently been changed as the gaskets in both look like new. Perhaps was done less than a year ago by the driveline shop in Sparks, NV. However, the gasket in tranny and transfer case looks old.

Having them flush the tranny and change gear oil in the transfer case will cost me $400.00, which is fine with me. Auto repair here in the SF bay area is probably more expressive than anywhere else in the USA as all property is very expensive here, business or homes (average home price here is more than a million bucks).

This kinda work I have done myself on my other Jeep (97 Jeep Cherokee). But since this 99 Jeep is in the shop now, I will let them do it.

BTW, what would I expect a tranny flush and transfer gear oil change to cost in other parts of the country?

Anyway, the new front drive shaft and labor for such is not costing me anything. I am simply paying the price for the tranny flush and transfer oil case change. But putting the shaft in only takes a few minutes anyway.

As an interesting side note, when I went to the dealer to buy a part (unrelated to all this) a few months ago, I had to use the VIN number. And the Jeep dealer in Reno mentioned who owned my Jeep last before I purchased it from a used car lot. It was last owned by a well known local multimillionaire, John Ascuaga, who used to own the Nugget Casino in Sparks. He is quite old, but I have ran into him a few times in the Reno area and I even told him that I now own his Jeep. But who knows how many vehicles he has owed. He is now too old to drive himself anywhere, but I doubt that has ever been a problem for him.

BTW, this 99 Jeep has a 4.7L engine and has a lot more power than my 97 Jeep which has a 5.2L engine. I wonder why. My 97 Jeep seems normal, but this 4.7L Jeep accelerates much like I would expect from a race car. Perhaps that's why the shaft didn't last long.

-Don- SSF, CA

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Originally Posted by DonTom

BTW, this 99 Jeep has a 4.7L engine and has a lot more power than my 97 Jeep which has a 5.2L engine. I wonder why. My 97 Jeep seems normal, but this 4.7L Jeep accelerates much like I would expect from a race car. Perhaps that's why the shaft didn't last long.

-Don- SSF, CA

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Maybe it was a stronger engine when new, or maybe the smaller engine was hot rodded.
Somewhat more likely, the ring and pinion in both axles may have been changed to a numerically higher ratio, which would make the Jeep better for rock crawling and for drag racing.

If you're under it again, you might count the driveshaft turns it takes to make the wheels go around once, and compare that with the stock axle ratio.

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Originally Posted by MikeHalloran

Maybe it was a stronger engine when new, or maybe the smaller engine was hot rodded.
Somewhat more likely, the ring and pinion in both axles may have been changed to a numerically higher ratio, which would make the Jeep better for rock crawling and for drag racing.

If you're under it again, you might count the driveshaft turns it takes to make the wheels go around once, and compare that with the stock axle ratio.

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Perhaps one other thing I can do is compare the RPM's at several steady speeds and compare to my 97 Jeep. I too have wondered if the difference was just gearing.

-Don- SSF, CA

Just had a quick browse round the net - loads of half conflicting info out there. Best info I can get is;

'99 4.7L 235 HP and 295 lb ft torque. Base weight 4050lbs, gross 5500lbs.

'97 5.2L 220 HP and 300 lb ft torque. Base weight 4056lbs, gross 5368lbs.

Looking at the figures there it would not seem that there was much difference between the two so gearing may be the major factor to any acceleration differences.

Ken.

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Originally Posted by Ken

Just had a quick browse round the net - loads of half conflicting info out there. Best info I can get is;

'99 4.7L 235 HP and 295 lb ft torque. Base weight 4050lbs, gross 5500lbs.

'97 5.2L 220 HP and 300 lb ft torque. Base weight 4056lbs, gross 5368lbs.

Looking at the figures there it would not seem that there was much difference between the two so gearing may be the major factor to any acceleration differences.

Ken.

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Even there, isn't it surprising that the smaller engine has 15 more HP? But I also noticed the 5 lb ft less torque in the spec. with the smaller engine.

But with the more HP and possible lower gearing, could be the answer.

The difference between the two is very noticeable in acceleration. Seems like a more than 15 HP difference.

There's a small chance I could get my 99 Jeep back today. The front drive shaft is expected to be here at 1400 hrs via UPS. It only takes a few minutes to install.

But I always expect things to not go so smoothly. That way, I am less disappointed.

We wanna get back to Reno, bored with this area already.

-Don- SSF, CA

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Originally Posted by DonTom

Even there, isn't it surprising that the smaller engine has 15 more HP? But I also noticed the 5 lb ft less torque in the spec. with the smaller engine.

But with the more HP and possible lower gearing, could be the answer.

The difference between the two is very noticeable in acceleration. Seems like a more than 15 HP difference.

-Don- SSF, CA

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Back in the day when I used to tune engines for road and competition use the target was to try and beat 100 BHP/liter. Figures like that are now pretty commonplace on standard 'bike road engines - my old 0.6L Honda knocked out around 110 BHP and my 0.8L tourer pumps out well over 100 BHP. Cars still seem to lag quite a long way behind, my Mazda 2.0L still only puts out 135 BHP. For 'bike engines one is only starting to talk 'performance' at around the 170/200 BHP/Liter. I guess most of the power we take for granted now comes from the enormous advances in material technology, it would be nice to see what I could do with one of my old Mini/Mini Cooper engines using modern materials for liners, pistons, rods, cranks, valves etc.

Ken.

Here is an update.

I got my Jeep back today. All this turned out a lot better than I expected. The shaft was delivered overnight and this breakdown really did not cost me a cent. I simply paid for a tranny flush and a transfer box gear oil change, which I wanted to have done anyway. I was charged almost $100.00 LESS than my estimate. Total bill was $315.00. Since it didn't take long to put the new front shaft on (only takes a few minutes--simple job) it simply came with the deal.

I am very happy with all involved, the drive line place as well as the tranny shop.

We will be headed back to Reno in an hour or two. We usually drive at night, when traffic is very light.

-Don- SSF, CA

The difference between the engines is vast. Your 5.2 Magnum was the third iteration of that type engine. The Magnum came out in '92. It replaced the LA small block that first came out in 1964. It got updated over the years but until 1988, it was almost always the same engine. In '88 they got fuel injection and roller lifters. Before 1964, the engine was used in a Hemi configuration in the 1953 Dodge cars. The 4.7 on the other hand is a second generation Magnum engine. It has overhead camshafts that free up a lot of parasitic loss, has better internal flow of the intake and exhaust and so on. Add in better computer controls, lighter materials, lower friction coefficients and the engine will really put out. I've got an '01 Ram 2500 with the 5.9 first generation Magnum and an '02 Grand Cherokee with the 4.7 second generation. Even with a rear end getting ready to go out, it's a peppy little thing. I got it to tow a trailer but it isn't up to it. I'll just keep the truck I've had for 5 years.

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Originally Posted by grouch

The difference between the engines is vast. Your 5.2 Magnum was the third iteration of that type engine. The Magnum came out in '92. It replaced the LA small block that first came out in 1964. It got updated over the years but until 1988, it was almost always the same engine. In '88 they got fuel injection and roller lifters. Before 1964, the engine was used in a Hemi configuration in the 1953 Dodge cars. The 4.7 on the other hand is a second generation Magnum engine. It has overhead camshafts that free up a lot of parasitic loss, has better internal flow of the intake and exhaust and so on. Add in better computer controls, lighter materials, lower friction coefficients and the engine will really put out. I've got an '01 Ram 2500 with the 5.9 first generation Magnum and an '02 Grand Cherokee with the 4.7 second generation. Even with a rear end getting ready to go out, it's a peppy little thing. I got it to tow a trailer but it isn't up to it. I'll just keep the truck I've had for 5 years.

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Thanks for all that info. Very interesting. But IYO, is the 4.7 as reliable as the 5.2? Other than the slightly higher torque of the 5.2L, are there any advantages of the 5.2L? And wouldn't your 01 Ram 5.9 even have a lot more torque? Wouldn't that be better for towing anyway?

-Don- Reno, NV

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Originally Posted by DonTom

Thanks for all that info. Very interesting. But IYO, is the 4.7 as reliable as the 5.2? Other than the slightly higher torque of the 5.2L, are there any advantages of the 5.2L? And wouldn't your 01 Ram 5.9 even have a lot more torque? Wouldn't that be better for towing anyway?

-Don- Reno, NV

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There's an old racers maxim. "There's no replacement for displacement". Bigger is more powerful. It's also more thirsty. That extra 1.2 liters does pull pretty good. I also get 12 mpg, on a good day, down hill, with a tailwind. Pulling a trailer it's closer to 8 mpg. The Jeep has a rear end that's going out and still get 16 mpg average. The 4.7 is a smoother engine and more efficient. It's just not enough to tow with. Once I get the rear end replaced, I'll probably sell it. My girlfriends daughter has my Focus so I want to get a larger car like a Town Car. Both of us are 6 foot tall and when we're in a Ford Focus, well, there isn't much room left.

This 1999 4WD Jeep which had the drive line noise problem and had both shafts replaced . . .and a year later the NEW replaced front drive shaft broke & was replaced again (under warranty, as mentioned in this thread) is now making drive line noise again. It's about 1.5 years since the front shaft was replaced under warranty. Replaced in May 2015.

I don't know if it's the front or the rear shaft making the noise this time. This noise is most noticeable at freeway speeds. I cannot even be sure this noise is coming from the drive shafts, but I think it is. The noise varies greatly, so does the vibration, sometimes quite loud, other times can barely hear it. But never when the vehicle is in neutral at freeways speeds even if at the same RPM (no load). This problem is only when accelerating, even if acceleration is very slight, or even if only pressing on the gas pedal to maintain speed.

I never had a drive shaft problem in any other of my vehicles. Could something be chewing up the driveshafts?

Early next week, I will bring this Jeep into the same drivetrain shop in Sparks, NV and see what they say

-Don- Reno, NV

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Originally Posted by DonTom

This 1999 4WD Jeep which had the drive line noise problem and had both shafts replaced . . .and a year later the NEW replaced front drive shaft broke & was replaced again (under warranty, as mentioned in this thread) is now making drive line noise again. It's about 1.5 years since the front shaft was replaced under warranty. Replaced in May 2015.

I don't know if it's the front or the rear shaft making the noise this time. This noise is most noticeable at freeway speeds. I cannot even be sure this noise is coming from the drive shafts, but I think it is. The noise varies greatly, so does the vibration, sometimes quite loud, other times can barely hear it. But never when the vehicle is in neutral at freeways speeds even if at the same RPM (no load). This problem is only when accelerating, even if acceleration is very slight, or even if only pressing on the gas pedal to maintain speed.

I never had a drive shaft problem in any other of my vehicles. Could something be chewing up the driveshafts?

Early next week, I will bring this Jeep into the same drivetrain shop in Sparks, NV and see what they say

-Don- Reno, NV

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The problem with noise is it travels in a unibody vehicle. I've hunted a noise at times almost to distraction. Sometimes you have to wait until the part is nearly ready to fail and the noise gets worse. If you have a lift kit, the differentials need to be "clocked" to reduce the angle on the universal joints. The mathematics are some complex that some engineers do nothing but drive line work.

Decades ago though, it was common to test vehicles to destruction. Now, the bean counters are involved and a test driver is under pressure to drive easier to preserve the equipment. Chrysler minivans got a reputation of weak transmissions in the 1990's. they were good transmissions. They just weren't designed for what people did to them. The 4 cylinder vans had the old 3 speed transmission and it was a slightly revised version of the Torquflite that had been made since the early 60's. The V-6 vans, which was most of them, got a 4 speed version with overdrive. Since a minivan only has so much room, the extra gear had to go into the three speed case. This meant everything had to be made lighter. With less robust parts, it still was a good unit IF you didn't hot rod it. Most of these were used to haul kids and I've seen many soccer mom's (and dad's) drive them hard. I have a Kawasaki Concours Sport touring bike that will go fast. I've had soccer moms try to get ahead of me when I'm enjoying the push of acceleration. This is a bike that will hit 150 with no sweat. She was trying to get ahead of me to change lanes when she could just drop back and then move over.

Head back to the driveline shop and see what they say. You may have gotten inferior parts, there may be a design flaw or you may be doing something that is causing this to happen. I'm assuming your Jeep hasn't been wrecked in the past. If it's a rebuilt, there are all sorts of things that can be causing this.

The driveline shop is closed on Saturday and Sunday, so I hope to take it down there later today (Monday). But I drove the Jeep yesterday and it hardly made any noise at all. Like it is getting better instead of worse, which is NOT what I want when I am about ready to bring it in to be checked.

-Don- Reno, NV

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Originally Posted by grouch

The problem with noise is it travels in a unibody vehicle. I've hunted a noise at times almost to distraction. Sometimes you have to wait until the part is nearly ready to fail and the noise gets worse. If you have a lift kit, the differentials need to be "clocked" to reduce the angle on the universal joints. The mathematics are some complex that some engineers do nothing but drive line work.

Decades ago though, it was common to test vehicles to destruction. Now, the bean counters are involved and a test driver is under pressure to drive easier to preserve the equipment. Chrysler minivans got a reputation of weak transmissions in the 1990's. they were good transmissions. They just weren't designed for what people did to them. The 4 cylinder vans had the old 3 speed transmission and it was a slightly revised version of the Torquflite that had been made since the early 60's. The V-6 vans, which was most of them, got a 4 speed version with overdrive. Since a minivan only has so much room, the extra gear had to go into the three speed case. This meant everything had to be made lighter. With less robust parts, it still was a good unit IF you didn't hot rod it. Most of these were used to haul kids and I've seen many soccer mom's (and dad's) drive them hard. I have a Kawasaki Concours Sport touring bike that will go fast. I've had soccer moms try to get ahead of me when I'm enjoying the push of acceleration. This is a bike that will hit 150 with no sweat. She was trying to get ahead of me to change lanes when she could just drop back and then move over.

Head back to the driveline shop and see what they say. You may have gotten inferior parts, there may be a design flaw or you may be doing something that is causing this to happen. I'm assuming your Jeep hasn't been wrecked in the past. If it's a rebuilt, there are all sorts of things that can be causing this.

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