On highway, clunk in driveshaft and won't shift or pass 60mph - JeepForum.com
 
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post #1 of 7 Old 02-14-2020, 03:43 PM Thread Starter
ClownInAJeep
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On highway, clunk in driveshaft and won't shift or pass 60mph

Hi all. I'm gonna try starting a new build thread later today. But thought I could put up specific problems that could relate to everyone here. This is what I'm driving:

2000 WJ 4.7 Quadra-Trac with 247 with approximately 190,000 miles

So I'm not sure if it's the transmission, rear driveshaft, throttle position sensor, pcm, transfer case, or rear differential. But the 2 main problems is:
1) When shifting from park and back and forth, most times there is a large clunk or jolt to get it in gear.
2)Driving down there highway as I pass 50mph but before 60mph, I will sometimes get a loud clunk and jolt in the rear (sounds like from driveshaft), trans sounds like it drops down a gear, and then stays in that gear hovering around 2,200rpm. And it won't go past 60mph. If I try, it starts to stutter as if about you stall.

I feel like I've read many similar types of threads on this sort of thing. But I'm horrible at assimilating all that info to accurately diagnose my troubles.

Much thanks for any tips.

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post #2 of 7 Old 02-15-2020, 10:21 AM
Bigrigr
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Two things jump out at me here....I think you have separate problems.

First, double check your exhaust system for a blockage. It sounds as though your engine is struggling to expel the exhaust out, and its smothering the engine. Most likely a plugged up Catalytic converter somewhere. this would be the cause of the struggling to get above 60 MPH.

Second, double check your engine and transmission mounts. One on either side of the engine down low(easily seen from underneath the front of Jeep), and one in the middle directly underneath the adapter between the transmission and transfer case(basically between the front seats underneath the Jeep). Sounds like one or more of them is shot, and letting the engine/trans/transfer case move around.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,3"BBfront,2"BBrear,JK'sW/32's
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post #3 of 7 Old 02-20-2020, 05:12 AM Thread Starter
ClownInAJeep
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Thanks so much for the tips! I pulled off the cat and put on another from the parts jeep. The engine stumbling has appeared to be taken care of so far. Although I have to admit I'm not so sure on what to be looking for with the mounts. But i'm thinking i might as well replace them if I can find some decently priced.
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post #4 of 7 Old 02-21-2020, 11:56 PM
Bigrigr
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The Engine mounts are on either side of the engine down low and just forward of center on the engine. They are easy to see from underneath the front of the Jeep.



If you get a helper,and your park brake works well, you can check your mounts by putting on the parking brake tight. Next hold your foot on the brake after shifting into drive, and using the other foot, rev the engine slightly. With some one outside looking under the hood, if the engine mounts are loose or broken, the engine itself will try to jump out of the engine bay. Usually you see the drivers side jump up when you bring the rpms up, and then it will fall back down when you let off the gas. Same process for the trans mount, except you have to have your helper watching under the Jeep at the crossmember. There should be a little bit of movement in all of the mounts, but if they move alot, then thats not good. The clunk would be the engine/trans moving excessively, and then crashing back down when you let off.


190,000 miles is alot of miles on ANY rubber mount. They probably all need replaced anyway.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,3"BBfront,2"BBrear,JK'sW/32's
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post #5 of 7 Old 03-27-2020, 04:42 AM Thread Starter
ClownInAJeep
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Just a quick note of thanks

Quote:
Originally Posted by Bigrigr View Post
Two things jump out at me here...I think you have separate problems.

First, double-check your exhaust system for a blockage. It sounds as though your engine is struggling to expel the exhaust out, and its smothering the engine. Most likely a plugged up Catalytic converter somewhere. this would be the cause of the struggling to get above 60 MPH.

Second, double-check your engine and transmission mounts. One on either side of the engine down low(easily seen from underneath the front of Jeep), and one in the middle directly underneath the adapter between the transmission and transfer case(basically between the front seats underneath the Jeep). Sounds like one or more of them is shot, and letting the engine/trans/transfer case move around.
Bigrigr- I know its been a minute since I posted about all this. But I wanted to thank you for your insight and advice here. You were spot on. I swapped in a converter from a parts WJ I have here, and wow! Improvement all around. I'll admit, I still got a lot to learn and took for granted how much the exhaust system can affect things. And on a whim (and seeing a deal on Amazon) I took the opportunity to swap out the muffler for a straight thru Thrush cherry pack, and that low grumble is so much more satisfying. I still need to replace the engine mounts but I got the trans mount swapped and haven't had that clunk on the highway since. But still a hard shift between D and R and P, so I'm assuming the engine mounts are contributing to that. Thanks again. Up next to fill the time while under quarantine is the axle swaps from my Quadra drive parts WJ along with a transfer case swap with a 242HD out of a 2002 V8 WJ. Here's to hoping I don't screw this up lol.
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post #6 of 7 Old 03-27-2020, 08:01 AM
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Quote:
Originally Posted by ClownInAJeep View Post
Bigrigr- I know its been a minute since I posted about all this. But I wanted to thank you for your insight and advice here. You were spot on. I swapped in a converter from a parts WJ I have here, and wow! Improvement all around. I'll admit, I still got a lot to learn and took for granted how much the exhaust system can affect things. And on a whim (and seeing a deal on Amazon) I took the opportunity to swap out the muffler for a straight thru Thrush cherry pack, and that low grumble is so much more satisfying. I still need to replace the engine mounts but I got the trans mount swapped and haven't had that clunk on the highway since. But still a hard shift between D and R and P, so I'm assuming the engine mounts are contributing to that. Thanks again. Up next to fill the time while under quarantine is the axle swaps from my Quadra drive parts WJ along with a transfer case swap with a 242HD out of a 2002 V8 WJ. Here's to hoping I don't screw this up lol.
I would also check the rear driveshaft U-joints; I have a 2007 that had a clunk on the back and also hard shifting, when the U joints where changed it went away but it came back with time; my trans mount is shot now and that's whats causing that clunk.

Hard shifting could be the trans needing service (although the mounts and u joints contribute more), filters and fluid unless it was done recently (think its every 100,000 km).
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post #7 of 7 Old 03-27-2020, 11:49 PM
Bigrigr
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Quote:
Originally Posted by ClownInAJeep View Post
Bigrigr- I know its been a minute since I posted about all this. But I wanted to thank you for your insight and advice here. You were spot on. I swapped in a converter from a parts WJ I have here, and wow! Improvement all around. I'll admit, I still got a lot to learn and took for granted how much the exhaust system can affect things. And on a whim (and seeing a deal on Amazon) I took the opportunity to swap out the muffler for a straight thru Thrush cherry pack, and that low grumble is so much more satisfying. I still need to replace the engine mounts but I got the trans mount swapped and haven't had that clunk on the highway since. But still a hard shift between D and R and P, so I'm assuming the engine mounts are contributing to that. Thanks again. Up next to fill the time while under quarantine is the axle swaps from my Quadra drive parts WJ along with a transfer case swap with a 242HD out of a 2002 V8 WJ. Here's to hoping I don't screw this up lol.
Thanks for getting back to us on this. Im glad to be of help. Heaven knows i have learned alot on this forum since trolling around here. Its good to contribute. I just completed a Vari-lok axle swap into a 99 laredo with a 4.0L and a 242LD. The axles were a plug and play. The 242HD should be as well, as long as you have the rear driveline from the donor. The only problem i have heard of, has been an issue with rerouting the shift cable to the transfer case through the retaining bracket. Some people say they dont have a bracket with two holes in it(which is what you need). But i have never seen a WJ without the two holed bracket. You might just wanna double check before you start the swap to insure you have eveything you need. Good luck!

P.S. what is your engine idle speed? If your engine is idling to fast it can cause a hard shift into Drive or Reverse from Park.....

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,3"BBfront,2"BBrear,JK'sW/32's
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