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Discussion Starter · #1 ·
New to this group having just purchased a 2006 quad cab 3.7 6-speed with 25Kmi. Over the holidays I drove about 1500 miles, half towing about 3200lbs. While not exactly speedy, performance was fine with decent fuel economy (21 mpg with an empty tow dolly & 18 loaded, running 70-75 mph)

Besides the water leak I discovered today, my truck makes a noise that doesn't seem quite right. When accelerating at moderate throttle, there's a distinct clattering sound. This seems to be worse after an extended period of driving. If it were a Cummings, I might think it was normal, but with a port injected gas motor, it doesn't seem right??? Any ideas as to the cause or is it normal for the 3.7?

How can I tell which diff my truck has?

Cheers,

Ken
2006 Quad Cab ST
 

· Devil's Advocate
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well if you have the 3.7 you'll most likely have the 8.25 rear end and im betting 3.55 gears...look at the sticker in the glove box
 

· Mopar Kid
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If I'm not correct you said the sound is coming for you motor not the rear? Does the truck have a lost of power or does it ride about the same? Any changes in Gas millage? Is the truck still under warenty? Yeah, your truck has to have 3.55 gears in it i couldnt see Them putting anything bigger!
 

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Discussion Starter · #4 ·
Thanks for the replies. There isn't any sticker in the glovebox. But my guess also was that it has a 3.55.

I've only had the truck a couple weeks and didn't notice the noise on the test drive. If I get into the throttle pretty hard I don't seem to hear it. Definitely coming from the engine bay. Waiting on the dealer to get a windshield as they were supposed to replace it before I picked it up. I'll see what they say about it when I take it in. I'd like to have some info up-front so I can counter the dealer "they all do that, it's normal" nonsense...unless of course they do all make this noise!

Cheers,

Ken
 

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well, I have an 07 3.7 with the 6 speed,. I have noticed a rumble noise too. It seems to only happen when the truck is at normal temps and as you said under load. This can be done easily by leaving it in 6th gear and accelerating slowly when the truck is cruising around 1500 - 2000 rpms. Its sounds like its coming from the back of the engine or maybe the exhaust manifold. I cant pinpoint it but I can recreate it, I am waiting to see if it gets worse but as you said,.. they may say its normal.
 

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I have an 07 3.7 and a 6M, and I can get what assume is the clutch damping assembly to make a real racket when I over-lug the engine; try, on an empty road, starting in 1st, then shift to 3rd or 4th and get on the gas...does the noise appear? When I was getting used to this truck, I had some near-stalls that generated a real stocatto, "Cummins-like" clatter from the drivetrain due to pulling excessively low RPM. Then I would either stall the truck or slip the clutch enough to get going again. :)

My other thought is exhaust related...I have a Flowmaster on mine, so it rumbles all the time, but medium-heavy throttle, low revs, (1500 RPM sounds just right) and a load (like going up a hill), really brings out the beast as far as exhaust rumble. I'm sure it's possible to get a little resonance even with the stock exhaust. Have you checked for a loose exhaust hanger?

I've learned to accept the clunks the Getrag 238 makes...especially the clutch actuating linkage when you let the pedal out into 2nd or 3rd without giving a little gas...the slack in the assembly get taken up with a nice sharp *clank* and away you go...

No harm no foul...if it still drives fine, no leaks or inconsistent behavior, it's probably OK. Says the non-Dodge mechanic. :crazy:
 

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Discussion Starter · #7 ·
Engine noise during accel

Thanks for the reply. Just before the holidays, the truck went into the dealer to fix the water leak. They found the windshield leaked and it was replaced. The engine rattle under accel they say is related to the tranny throwout bearing and were going to order one and replace it under warranty.

If I lightly accelerate, it does sound a bit like a diesel clatter or lifter or rod bearing rattle. Certainly nothing like any T-O bearing I've ever heard. If I get deeper inot the loud pedal, I don't hear the noise.

I also recently changed the plugs as it hit 30 Kmi. None of the plugs on the left bank were close to the correct torque. All 3 were barely finger tight and nowhere near as tight as the right bank plugs???

Cheers,

Ken
 

· Private Assasin
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I also recently changed the plugs as it hit 30 Kmi. None of the plugs on the left bank were close to the correct torque. All 3 were barely finger tight and nowhere near as tight as the right bank plugs???
If that's the case, you might see even more mileage/power.

I would HIGHLY recommend putting a cold air intake on the 3.7L...they respond VERY well. We put a home made one on my friends Ram 3.7L/5spd and it made a noticeable difference in acceleration and holding it's speed on hills. We later installed 3.92 gears which made it LOADS of fun to drive, plus it allowed for better power on the open road, actually keeping him from downshifting, and giving a little mileage improvement.

The 3.7L is a good motor, especially in a manual..they love to rev, and are based on the 4.7L, which are exceptionally stout engines.
 

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What did you use for the homemade CAI? What type of filter and what did you use for tubing?

I'm encouraged that the 3.7L has a good response to a CAI...esp a home made one at that.
 

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Discussion Starter · #10 ·
How about posting a pictures or details on the cold air intake you created? I saw no change in fuel eco after my plug change. Still seeing 18ish in town and 19-20 highway.
 

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Let me know if the TO bearing made a difference in the noise. I have a similar problem, and the dealer is acting dumb on the issue. They just want to keep troubleshooting at $70 and hour.
 

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Discussion Starter · #12 ·
Hi. I'm still waiting on the dealer to replace the TO bearing. They keep telling me it is on order. Once it's doen I'll let you know if the noise is gone.

Cheers,

Ken
 

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If the noise is what I think it is, it's gear rattle in the trans. I've been involved in lots of development on the clutch and disc for this transmission, and they are rattle traps.
Most dealers don't even know what gear rattle is, so they are not "playing" dumb....they really don't know what they are hearing.
The noise will generally get worse as the trans gets hot and the fluid gets "thinner". 1500 to 2200 RPM is where you'll hear it.
 

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Discussion Starter · #14 ·
Hi. Would the gear rattle be heard more during light acceleration in the rev range you mentioned? I rarely here my noise at idle, and I've been somewhat doubtful about the dealer dianosis as it does change with pressure on the clutch pedal. I generally don't hear it during hard accel, but engine noise may just cover it.

My main concern is that it not be an internal engine problem. If there really isn't a TOB problem and its just gear rattle, I'm inclined to not have the dealer pull things apart for the TOB.

Cheers,

Ken
 

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Light acceleration and the RPM range I mentioned is where you'll hear it. It varies greatly from truck to truck, but I have heard a couple trucks that it was very loud in. You won't hear much at idle....maybe a wee bit if you really listen close, but just off idle up to around 2200 is where it will really raise hell. Above that RPM it should start to clear up.
I really believe the diagnosis of throwout bearing is incorrect judging from your description of the noise.
Gear rattle, if that's what it is, won't hurt anything. It's just aggravating.
 

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I have an o7 3.7 with a mt and my truck has only 8k miles on it and ever since it was new, it will make that noise if I lug a high gear. I would put money on luvmy98s response. I couldnt see a Throwout bearing would be bad in my truck from day one.
 

· Private Assasin
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Bah..guess it would help if I actually answered the questions of me on the post. :crazy:

1) 3" ID air filter (Amsoil EAAU 3090)
2) 2 - 6" straight pipe sections
3) 2 - 90 degree elbow sections
4) 1 - 45 degree Ford PCV valve
5) 1 - 3" hose clamp
6) 1 - 1/2" rubber brommet for intake sensor
7) 1 - 1 rubber 3" coupler
8) 1 custom bracket to mount pipe to intake.
9) 6" piece of 5/8 heater hose

I bought everything at O'Reilly's but Autozone has it also (I bought the filter direct from Amsoil). Cost to build the kit is about $60, not including filter.
 

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