Crunching Shift
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Freshman User
Joined: Jun 2006
Posts: 26
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From: South of Atlanta
Crunching Shift
Hi all,
I have a 2001 Excursion 2WD with the 7.3 with Jody's 80 HP Economy tune on it. (love the tune by the way)
About a month ago it started doing something strange under hard accelleration. It used to easily bark the tires in 2nd gear if I was accellerating really hard, but the past 3 times it has shifted hard it has made a crunching noise instead. Two weeks ago I bought a 29' travel trailer and foolishly did not get the PCM reflashed to a towing tune. It made the crunch sound particularly bad on the shift to 2nd the first time I pulled it and had to pull into traffic. Under normal accelleration and driving it has no strange noises or characteristics. Great accelleration, strong shifts. I should probably add that it has 363,000 miles.
Lord willing it will keep on going another few years!
The crunch sounds like its coming from somewhere on the driver's side possibly rear end, but not quite that far back. I thought it was the rear end shifting at first, but everything looks exactly as it should back there. No newly exposed metal or anything. Drive shaft is solid as a rock. No leaks from anything. One additional detail is it has made a lesser version of this noise when accellerating from a stop, turning left especially, on a hill. Not crazy accelleration, but what you would normally do when turning left on a busy hwy in front of traffic. It's probably done that for 3 months.
Hopefully someone has experienced something like this before or has an idea, because I am about out of them.
Thanks!
Paul
I have a 2001 Excursion 2WD with the 7.3 with Jody's 80 HP Economy tune on it. (love the tune by the way)
About a month ago it started doing something strange under hard accelleration. It used to easily bark the tires in 2nd gear if I was accellerating really hard, but the past 3 times it has shifted hard it has made a crunching noise instead. Two weeks ago I bought a 29' travel trailer and foolishly did not get the PCM reflashed to a towing tune. It made the crunch sound particularly bad on the shift to 2nd the first time I pulled it and had to pull into traffic. Under normal accelleration and driving it has no strange noises or characteristics. Great accelleration, strong shifts. I should probably add that it has 363,000 miles.
Lord willing it will keep on going another few years!The crunch sounds like its coming from somewhere on the driver's side possibly rear end, but not quite that far back. I thought it was the rear end shifting at first, but everything looks exactly as it should back there. No newly exposed metal or anything. Drive shaft is solid as a rock. No leaks from anything. One additional detail is it has made a lesser version of this noise when accellerating from a stop, turning left especially, on a hill. Not crazy accelleration, but what you would normally do when turning left on a busy hwy in front of traffic. It's probably done that for 3 months.
Hopefully someone has experienced something like this before or has an idea, because I am about out of them.
Thanks!
Paul
Thread Starter
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Freshman User
Joined: Jun 2006
Posts: 26
Likes: 0
From: South of Atlanta
Thanks, Brent. Thankfully that's about what we found. My brother and I got under it yesterday and started looking around. There are two nuts that hold the rear transmission mount isolator down to the crossmember that are moving.
It has cleaned the metal about a quarter inch fore and aft. I am wondering if maybe the slip yoke in the tranni needs greasing.
The two nuts look like they are only supposed to be 69 ft/lbs from what I can find on alldatadiy.com. Seems low but I guess that would be fine if the slip yoke was doing its job.
I'm planning on removing the drive shaft tonight, regreasing the slip yoke, reinstalling with new axle pinion flange bolts, and re-tightening the isolator to crossmember nuts.
If you have any advice on any of that I'd appreciate it much.
It has cleaned the metal about a quarter inch fore and aft. I am wondering if maybe the slip yoke in the tranni needs greasing.
The two nuts look like they are only supposed to be 69 ft/lbs from what I can find on alldatadiy.com. Seems low but I guess that would be fine if the slip yoke was doing its job.
I'm planning on removing the drive shaft tonight, regreasing the slip yoke, reinstalling with new axle pinion flange bolts, and re-tightening the isolator to crossmember nuts.
If you have any advice on any of that I'd appreciate it much.
