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-   -   Extremely Frustrated (http://www.jeepgarage.org/f73/extremely-frustrated-15093.html)

dowdy85 11-13-2010 08:13 AM

Extremely Frustrated
 
I am extremely frustrated with the transmission/engine in the 5.7 Overland. I am constantly hearing a vibration from the car (they are replacing the axle isolator this week). I'm not sure that will fix it. I am also annoyed because it feels like the car is slowing down instantly as soon as I left off the brake. I can be cruising downhill at 50mph and let off the gas and the car slows down. Is that normal? The dealership told me it is because of the MDS. However, as soon as I put the car in neutral it just takes off (as if it were) accelerating down hill. It is almost as something is geared wrong with the transmission.

Dunecrawler 11-13-2010 08:19 AM

Re: Extremely Frustrated
 
What was your build date?

Have a look at:
http://www.jeepgarage.org/f107/did-shudder-tsb-fix-a-problem-2011-shudder-problems-thread-12530-5.html

moosehead 11-13-2010 11:11 AM

Re: Extremely Frustrated
 
Sorry to hear OP, it does sound unusual. Hope you press the dealer for a solution and that it works out, please let us know.

GlowingGhoul 11-13-2010 11:13 AM

Re: Extremely Frustrated
 
Quote:

Originally Posted by dowdy85 (Post 300652)
I can be cruising downhill at 50mph and let off the gas and the car slows down. Is that normal? The dealership told me it is because of the MDS. However, as soon as I put the car in neutral it just takes off (as if it were) accelerating down hill. It is almost as something is geared wrong with the transmission.

Mine does this too, and I believe it's simply normal engine braking. In fact, the effect is much less pronounced on level roads for some reason. I wonder if the vehicle sensors select a different gear if you're on a steep grade....

Every automatic I've owned 'loosens' up in neutral, which makes sense since neutral takes the engine completely out of gear.

GlowingGhoul 11-13-2010 11:17 AM

Re: Extremely Frustrated
 
Oh, and by the way, I had a constant, teeth rattling vibration for the first 100 miles in my new Overland. The ride was "brittle". I discovered my tires (20's) were 8 PSI too high. Once I dropped them to 36, the vibration went away and the ride smoothed waaay out.

I know it sounds crazy, and I wouldn't have thought an extra 8 PSI would cause so much trouble, but it did.

whatevrworks 11-13-2010 11:47 AM

Quote:

Originally Posted by dowdy85 (Post 300652)
I am extremely frustrated with the transmission/engine in the 5.7 Overland. I am constantly hearing a vibration from the car (they are replacing the axle isolator this week). I'm not sure that will fix it. I am also annoyed because it feels like the car is slowing down instantly as soon as I left off the brake. I can be cruising downhill at 50mph and let off the gas and the car slows down. Is that normal? The dealership told me it is because of the MDS. However, as soon as I put the car in neutral it just takes off (as if it were) accelerating down hill. It is almost as something is geared wrong with the transmission.

That engine braking you are feeling is apparently normal. I have it on my 5.7 too and from talking to some friends their Mercedes has that same feel as well.

Bmwister 11-13-2010 12:20 PM

Re: Extremely Frustrated
 
I, too, believe that engine braking effect you experience is normal. The shudder is not and as a previous post indicates you would do well to check your tire pressure (cold). The 5.7 versions I test drove all did have the same "braking effect" upon throttle lift-off. FWIW, our Mercedes E550 also does that when going downhill. Even though the 5.7L trans is not the Mercedes unit (the V6 uses the Mercedes 5spd), the Germans may have pushed this effect during design to help improve the longevity of your braking system in such a heavy vehicle.

The braking effect when you let off the accelerator actually makes for a more relaxed driving experience, IMHO, when on the highway with lots of hills and moderate to heavy traffic. Just keep your foot on the gas and modulate the pressure to adjust speed up/down in varying speed conditions. I am one who gets fatigued far more easily if I have to go from gas to brake (or full foot off gas) to maintain speed downhill or in varying speed conditions as I do in our 06' Expedition. In the Mercedes it gives me the feeling of control I have when driving manual transmission vehicles.

A possible side-benefit to this braking effect is that it makes you less conspicuous to highway troopers who look for weaving and lots of braking when picking a "target" out of a flow of speeding traffic...at least that's what two of my IL state trooper friends do. You can just cut throttle and drop speed from the pack and let others show their brake lights.

Eurosport 11-13-2010 12:27 PM

Re: Extremely Frustrated
 
i think you're just too used to domestics that just coast and coast w/out engine breaking being noticeable, some coast even when you lightly brake lol no signs of slowing down...

euro's use level sensors on control arms or tie rods or middle of the car etc. that send signals to the ecu/tcu/dm, when going downhill you'll notice engine breaking, shifts, hunts for right gear depending on the surface level, etc. going uphill downshifts, etc. that's all normal,
try driving a VW DSG tranny for some "weird" experiences on inclines and driveways hah :D

moosehead 11-13-2010 12:32 PM

Re: Extremely Frustrated
 
OK, you guys now have me worried. I'm all for engine braking in say lower gears or in an autoshift or triptronic tranny setup. Do it all the time in the mountains for some of the benefits mentioned above.

That said, there should be a high enough gear in auto for any vehicle to allow reasonable downhill coasting speeds without excessive engine, trans, or 4wd system drag. Tell me that's the case here.

GlowingGhoul 11-13-2010 12:41 PM

Re: Extremely Frustrated
 
Quote:

Originally Posted by moosehead (Post 300747)
OK, you guys now have me worried. I'm all for engine braking in say lower gears or in an autoshift or triptronic tranny setup. Do it all the time in the mountains for some of the benefits mentioned above.

That said, there should be a high enough gear in auto for any vehicle to allow reasonable downhill coasting speeds without excessive engine, trans, or 4wd system drag. Tell me that's the case here.

Relax. It's not excessive at all. It's only noticeable if you NEVER had any engine braking effect with an auto. I just drove a MB CLS550 sport sedan, and it does the same thing.

Like the previous poster said, it feels GOOD :)

moosehead 11-13-2010 12:50 PM

Re: Extremely Frustrated
 
thanks gg, didn't want to spend the day turning coal into diamonds


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