MPG going upward

geordi · **Posted:** Fri Mar 15, 2013 9:32 pm

thermorex wrote:

racertracer wrote:

thermorex wrote:

So on the other hand it doesn't sound logical... But if racer said that, I don't see why wouldn't be true. Could be possible to be other factors he missed?

At first I thought I needed a new TC ... again. The shake was so bad that it caused my teeth to tickle my gums. the ujoint was frozen.

The jeep came from the Boston area. I believe that the previous owner just let it sit in his driveway after going through mounds of wet road salt and never washing the underneath.

I just can't believe the difference, really. It's night and day, I love it even more now.

There are people that don't even think those things are supposed to be lubed/greased every 3000 miles... White grease on the rings, grease all over.

And yes, never heard of such a stuck joint, lol. Glad you figured it out!

Might have something to do with my growing up in non-snow climates... But I am firmly one of those people you just mentioned. Since I started driving I personally have owned 3 FWD, 5 RWD (2 RVs), and 2 4WD vehicles. My family EACH drives more than 30k a year (we killed a 3/36 warranty in 13 months - still have that vehicle) and I can honestly say that I have --NEVER-- serviced any of the driveshafts on any of those vehicles. Only ONCE has there been a problem with a universal - on an 83 Lincoln Town Car, it broke the rear joint after over 200k miles. Snapped an ear right off. The only other problem has been a continual balance issue on the minivan with the passenger axle and CVs. It broke one in the same way as the Town Car, and we have tried about 4 times to get a CV that didn't vibrate like crazy. I still need to solve that one, but with 230k miles on it... Obviously it hasn't broken anything else on the engine!

Every 3k miles, those need service? What kind of hell do your vehicles live in?

thermorex · **Posted:** Fri Mar 15, 2013 11:45 pm

Lol Geordi, sometime to be honest they go through hell... Mud, salt, water... Really, maybe my memory gets worse as I get older, but I remember reading in a jeep book a while ago (fsm, or maybe my Cherokees book) about axle and chassis maintenance, they stated some like 3000 miles. White grease (spray from any autoparts) at the joints since it prevents water to get in and then lube whole thing with a thick grease (I use regular), the excess is anyways thrown out when it starts spinning. Liberty's only 2 exposed cv joints at the rear drive axle maxes it easier and faster than other cars (like cherokee or wrangler where you also have the front drive axle plus the drive shafts).

geordi · **Posted:** Sat Mar 16, 2013 12:36 am

Yeah, I've seen people on here and other Jeep boards talking about ridiculous maintenance items too, like the differentials and the transfer cases.

Well over 240k on the 97 Grand Cherokee that we still own, and it has only ever had the rear diff serviced when it developed a whine and promptly ate itself... After pushing that Jeep over 200k miles! Change the diff oil? I'm not proud to say that it never has been... just that it has been forgotten and obviously isn't as critical a maintenance item as some would make it seem. I'd even suggest that +200k miles is a perfectly acceptable service life from the entire differential, whether the oil was changed or not. The transmission which WAS serviced regularly didn't make it much more than that, and the engine is certainly feeling tired these days. I'm not sure whether it has a leaking cylinder or not, but it has a worse gasoline habit than any other vehicle we own, the RVs included. A lot of road has passed under it however, so we really can't complain too much.

Joe Romas · **Posted:** Sat Mar 16, 2013 9:15 am

Last June I was following a newer 2007+ Liberty on the interstate and heard what sounded like an explosion :dizzy:

Looking under that jeep I saw the rear end of the drive shaft spinning around wildly and it was glowing red hot :dead:

I wonder what indication if any the driver might have ignored before this happened?
We were towing our travel trailer the following week so at 54k miles I dropped the drive shaft, removed the U joints for inspection.
Now I have driven on the beach of NC in salt water and live in the snow belt but there was no rust in the joints. But there were wear marks on the front joint bearing surface where the needle bearings ride.
Off to NAPA for new MOOG joints. When installing them I found the needle bearings in the originals to be about 1/8" shorter then on the replacements, another bean counter feature. Replacements were not a deal breaker at around $14 each :2cents:

kjjet · **Posted:** Sat Mar 16, 2013 10:17 am

Srytrucker wrote:

kjjet wrote:

Your the 2nd i've heard had to replace them. The 1st was due to vibration. Going to have a close look at mine. racertracer....did you see anything prior to removing?

My MPG went up when I rebuilt the Emergency brake's. I can get as much as 550 out of a tank in the CRD. But over 700 in the TDI. That thing rocks!

I need help with that as my e brake setup is rusted and causing sticking on rear brakes , in turn loss of MPG, actually that also caused my rear rotors to wear uneven too.
So can you please give me the part numbers and source from where you got them.thanks

This is what i did. At auto parts store. Got New, Rotors, brakes, E-break, E-brake hardware kit. What happens is there is a 2 piece e-break arms that rust together causing the e-break to stay on. Screwing everything up. Those arms can be replaced, but are only from Jeep. About $30 each if i recall. I removed mine and bead blasted them then used grease on them. you also can get a small plastic washer to go between them so they don't rust together. You will find there is not much room to work. Not fun.

Good luck,
KJJET

geordi · **Posted:** Sat Mar 16, 2013 12:28 pm

I'm a bad boy... While replacing the rear disc pads on my KJ, I discovered the e-brake drum pads had completely disintegrated, for reasons that still escape me. I never used the thing.
I didn't feel like learning how to reassemble that ouiji-board design of springs and levers, and I didn't have another vehicle to go get replacement pads anyway... So I figured out how to crank them in to their 'new pad' position and left them like that. The handle flexed the cables VERY smoothly after that!

On the VW, the same disc brake piston that is hydraulically actuated by your foot... Is also the cable-actuated E-brake. Quite an ingenious design, it rotates the piston out via a screw hidden inside the thing, so your service brake and e-brakes are both always exercised and don't get the opportunity to rust.

Unfortunately, it also means that changing the pads are a PITA, because you have to wind that piston back in with a special tool... Or a really strong swivel-head C clamp.

Srytrucker · **Posted:** Sat Mar 16, 2013 1:45 pm

In my case it is not the e brake pads but the shield in the back that is rusted and causing sticking and friction, even the new rotors are starting ti wear uneven as I can see the lines and two distinct shades on the new rotors. I am thinking of chucking the entire e brake setup if I can get away with it .

Srytrucker · **Posted:** Sat Mar 16, 2013 1:47 pm

Getting back to the topic can we get some pictures and pointers to check if there is any similar damage to our CRD.

dirtmover · **Posted:** Mon Mar 18, 2013 8:01 am

Joe Romas wrote:

Looking under that jeep I saw the rear end of the drive shaft spinning around wildly and it was glowing red hot :dead:

I wonder what indication if any the driver might have ignored before this happened?

Now, this one probably really did have a 3-5mpg hit before the u-joint disintgrated.

racertracer · **Posted:** Tue Mar 19, 2013 5:44 am

dirtmover wrote:

Now, this one probably really did have a 3-5mpg hit before the u-joint disintgrated.

My Jeep was purchased with 36,500 miles on it last year. It still had the original air filter in it. It sat in a wet yard for years, the rotors and pads had to be replaced due to the rust, the mechanic said that everything else worked fine even though rust was everywhere. So I had it derustoed with rust preventative and undercoating.

A month later the TC took a dump and the F37 was performed and one UJoint was replaced.

When I picked it up, the TC shutter was gone and the mild shake I felt at high speed was told to me to be an unbalanced tire. The tires were almost brand new so I had the tires balanced and rotated, but still the mild shake was still evident. The tire shop said that their maybe a bad tire causing the shake but they can't determine it. Everything looks good they said.

I had another Jeep dealer look at it from a front end and suspension point of view to determine if it was a
ball joint or shocks and they determined that the rear springs sagged and needed replacement along with the upper ball joints and all were replaced under the Chrysler service contract. The dealer said that all the Ujoints looked good. I was glad the work was done but the mild shake at high speed was still there, the problem was not solved.

Well, I thought that I might have to replace the tires then, so I replaced them with Goodyear Tripletreads and the problem didn't go away.

Still the mechanics said all looks good under there.

My mileage was low from the start, compared to my previous CRD mileage was never great from the day I drove it out of the wet grassy yard up in Boston.

About a month ago the shake began to increase at low speeds, and it felt like the TC was the problem again. My warranty had run out so I took it to AAmco Transmission for a free inspection and it was determined that it was a frozen rear Ujoint.

Took it home, replaced the Ujoint (with difficulty) and the Mileage slowly shot upward with smoother gear shifting.

This is what happened, I have no reason to bull doo doo, my intentions are to make this vehicle a better vehicle for me and adding to this board is a good thing since it helps me also.

Dirtmover, I hope this helps you better understand what can happen with Ujoints.

kjjet · **Posted:** Tue Mar 19, 2013 8:29 am

I will be taking a close look at mine today. I would guess it would be best to use jack stands so the wheels can spin during inspection.

My MPG has been good since repairing the E-breaks, but it never hurts to look and give some lubrication.

MPG going upward

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