Ok....this is a strange one....I have a strange thrumming noise at about 25-30 miles and hour. I simply coast and I feel a thrum...thrum....thrum.....I even put it in neutral while coasting and it is still there...it's really baffling and bothersome.
I recently had my pinion seal replaced on the rear end but that shouldn't cause any problems as I marked the driveshaft bolt and marked the flange on the axle so that they were put into the same spot by the tech. Not that I didn't trust them , but you never know.....

Here is what I checked:
-tire pressure
-tire rubbing
-brakes
-all weights are still on wheels
-all lugs torqued to spec
-front wheel bearings

I am wondering if my rear Diff oil needs changing? I just had the tires balanced back in April and I just recently rotated them.
It's hard to explain but it feels like it is coming up from the floorboards and the sound is audible. I just want to get to the bottom of it before any damage occurs.

Please....any other things to check/etc/help is greatly appreciated so that I can solve this pestilence!!!!

Thx friends!

Paul G.

 

Not a whole lot to offer here, but I was going to start a thread for the same thing at 90 to 100 mph. I've read about driveshafts being difficult on the F150's in general at this speed.

I've had my problem since new and want to resolve it as well. My other big gripe is that at 90 km/h, or ~55 mph, I don't even have to look at the speedo to see how fast I'm driving. I get a nice vibration that covers a 5 mph window. Feels like a roller bearing vibration. Again, since new although it was reduced with a transmission replacement.

Please help us.

Hey Paul,

When are we going to get together? I want to hear your Borla so I can order it if I like it. Really wanted to see your lowering job too, but I guess that is kaputs. Any way, let me know. The snow will soon fly and you or Snowplow are sure to lose an L one of these times.

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2000 Red Lightning Born 3-8-00 / Delivered 3-22-00
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Best time: 13.45 sec. @ 101.99 mph

2000 Red Trans Am Ram Air WS6, 6 Speed - Delivered 2-15-00 - Awesome Looking Car

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[This message has been edited by WHAT04 (edited 10-24-2000).]

 

Yeh, what Tim siad I wouldd like to hear the Borla as well.

Sorry but I can't think of what could be the cause of either of your thrumming problems. I have not experienced either of them, but I do have 2 problems of my own that I have not heard discussed here.

At around 3200rpm on an upshift I hear a consistnat rattle from about 2800 to 3200 when it shifts, but only on the 1-2 shift. If the shif is anywhere else it's fine. Strange.....It sounds a little like an exhaust/heat shield rattle. The other problem is sometimes when I start the truck it sounds like I have a big *** fan running under the hood. The sound gets louder as I give it more throttle. While this sound persists there is no boost/power no matter how much throttle I give here. It goes away after about 30 seconds of driving and then I can hear the whine of the charger again and I have boost/power. Seams like a belt slippage problem but I can never predict when it will happen. I would also expect to be able to smell something if the belt was slippinng. I hope I don't have a bearing problem on the supercharger.

Went to Cayuga last Friday (spur of the moment thing). Best run was a 13.639. There was a stock 97 Cobra there that was running consistant 14.1xx. My buddy got his stock R/T to run 14.8xx. (my reaction time is so bad he almost beat me to the end....boy am I a slug at the tree. I have yet to do better than 1.1 seconds !!!) We got about 20 minutes of video as well. All in all a lot fun. Got the L dyno'd as well and was making 347rwhp and 398rwtq. Getting all the time slips dyno plots and pictures scanned eventually. The spring will be time enough for more go fast goodies, but for now it's almost time to put the snows back on. We should get together some time. I would like to meet both of you and compare notes on problems/quirks etc. etc.



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99 Lightning in Pull me over Red.
- Build...#1869, June 2nd 1999. 1 of 1533 red
- K&N Filter Charger Kit.
- PSP Chip
- Bridgestone P245/70/R16 Winter Dueler's, on steel rims.
- Best time to date 13.572

Email me at bowerina@aci.on.ca