I have a 2001 SCrew that I've had since March of 2000 (First one in the state of Maine). I currently have over 54,000 miles on it and have never experienced any type of Thunk. After reading this lenghty thread, I tried to make my truck THUNK. I just can't do it....I must one of the lucky ones.
Dan.

 

You are one of the lucky ones... I thunk like a **** lately...

RP

 

After reading all these posts in this thread, I think I have experienced both "thunks". The one from a dead stop and also the on accelerating from ~25 m.p.h., but not all with the same truck.

About 4 years ago I test drove a '97 4x4 Lariat SC for a couple of days. When starting off from dead stop, after moving forward about 20 feet or so, there was a really noticable "thunk" coming from the rear end. I had my dad watch the rear end as I took off, and had him drive while I watched. Felt like the rear end was loose and the yoke was slapping the bottom of the truck., but could see nothing moving. That is why I didn't buy that truck.

I have just recently noticed the other "thunk" in the truck I just bought a couple months ago. After coasting without braking, down to about 25 mph, get a "thunk" when getting back on the throttle. This "thunk" feels like driveline slop to me, or else the torque converting locking a split second after reapplying the throttle and causing the driveline to shudder. The location of this "thunk" sounds to me like it is at the rear of the tranny.

Opinions?, Thoughts?

Oh yeah, I forgot. I traded a '99 for the truck I have now. Bought it new. Same exact drivetrain. That truck had no thunk at all.

 

I just bought a used 2001SCrew and have the thunk. I took it to a transmission guy who hooked it up to the computer and the throttle position indicated that the throttle was much more open than it was supposed to be at idel. Thought that the indication may be causing the thunk so replaced the TPS. Did not help.

Any solutions to the thunk, is it a re programing issue?

 

Never really did ever figure it out. I was told on several occasions to some degree it was normal though that did not seem to make sense to me. So far I now have almost 95k miles on it and many of those were towing a 5k boat for thousands of miles. It has so far given me no direct troubles though now I occasionally hear ticking noises....

 

Wow, talk about going back into time; this is an old thread. In any case, my truck has had the infamous "thunk" since I bought it with 40k on it. Did you fellas ever reach a conclusion as to why our trannys make that noise? Is it hurting anything?

-Craig

 

I will say that in the 4 years since this thread started, I have had the thunk in my '01 S-Crew and it has caused no issues in the last 70,000 miles. So, apparently it isn't an issue- just a quirk of the truck. It worried me at first but you learn to live with a vehicle's little traits like that. I still love my truck and would buy another one if it wasn't the wifey's turn for a new vehicle next. LOL

Amazing- this is a loooong thread.

UFM82

 

...at how much money you're spending on Candy Baby!

 

Well, apparently this thread will never die. I have a 2005 Screw with the same problem. Jeeeesh!

 

Same problem here. 2005 Supercrew FX4 with a few driveline issues. I get the pretty good clunk when accelerating after coasting to around 20 mph. Also, while coasting down, right at about 20 mph, the downshift from 3 to 2 is quite noticeable. I can feel the truck slow down and the engine rev a bit, kind of like downshifting with a manual when engine braking. Finally, I get a clunk or slight vibration when accelerating from a stop. Glad to hear I'm not the only one with these problems. I plan to take it to the dealer for a check up.

 

I think you hit the nail on the head!

 

NO, the chip (or pragrammer in my case)has zero effect on the thunk. I started with a superchip programmer. Loved it. Very powerful, no thunk issues at all at first. Of course, the truck was quite new. Then I switched to the edge with a display. Almost as powerful, but more adjustable. Of course, I used it in HighPerf mode all the time. Except when gas prices are high, then I use regular. I digress. After the thunk became more pronounced, I played with the programmer a lot to change the transmission settings, trying to affect the thunk. No matter what settings, the thunk was constant. Therefore, it's not the programmer (or chip)
Here's the dirty scoop on the thunk. Mine is an '04 supercrew. I bought it new with no issues save a slight leak in the transmission. The dealer "fixed" the leak three times. The last time they fixed it, they replaced the transmission case. I wonder how much grease they put in the slip shaft! Soon afterwards I started getting a very slight thunk (and a slight tranny leak) The dealer told me the thunk was "normal". BS! At about 50K miles, I noticed it getting worse. Especially when it's hot out. In mid winter in New England or Wisconsin, no thunk. I live in Louisiana. Of course, it's now out of warranty, right. So, I took it to aamco. I spelled that with lower case for a reason. They told me it was the rear diff. (ltdslip) I challenged the mechanic. He lost. There was no wear or debris in the diff case. Saved that $1800. I read on here someplace that the problem is in the driveshaft at the transmission yoke. Whatever that is. This is a two piece driveshaft btw. Well, today, with 150K miles, I dropped the drive shaft myself. It's sitting on the concrete under the truck. I've inspected it from end to end. NOTHING. No bad u-joints, or yoke that I can tell. But, there is NO grease on the slip shaft that goes into the transmission. It's a little oily, but otherwise clean. There are zero metal wear particles.
Here's the question. Where do you put 6 to 13 ozs of teflon grease? It must go into the transmission before the slip shaft, I guess. But 6 to 13 ozs? That's 3/4 of a cup minimum (apprx).
I'm going to take a shower and get some grease, and a super ball. The super ball goes in the slip shaft, from what I once read. Anybody heard of that?
I'm gonna leave you with this.....This truck is the best vehicle that I've ever owned or driven. I'd buy it all over again even knowing about the spark plugs and drive shaft thunk. My favorite vehicle was a '71 Porsche 914/6, but that's sooo different. You can't buy this truck from me. I can't replace it for 4 times the price. And this version is easily the best looking model! Who's lookin for a fight?!

 

This thread is from 2001, well before your body style existed, You are experiencing a different problem/clunk then this thread is discussing

welcome to the forums tho!