Howdy, this is my first time here...and here's the problem. I've got a 2001 TJ with the 4.0 and the 5spd. I've got the dana 44's and stock gearing/tires. The TJ has about 250 miles on it (just a bit green...hehehe). Anyway, I've noticed that at about 3,000-3,050 RPMs in 3rd gear I have a searious vibration that almost feels like a driveshaft...is this common? I don't think it's the tires since this only occures in 4th...I really can't feel it any other time. Thanks for the help!!!
HEY!-Have you ever had a new vehicle/motor before...'shesh'... your supposed to wait atleast 500-700 miles, I wait for 1000 miles, before you go over 60 mph or 3000 rpm!!!!!!! The motor and the rings need to 'seat themselves to make a good pattern inside the motor!!!!!! It will help in the long run for the motor!....a LITTLE green?!...not mad but a little frustrated...obviously nobody told you before...its like reading your vehicle manual and seeing it saying change your oil every 7000-9000 miles...
MARK (OIIIIO) LANGMOTORSPORTS
Mark, as much as I can agree with your thoughts on the perfect brake in for a motor...these are a little tough for me to do. I'm stuck driving on I-5 where the speeds range from 70-85mph on most areas. If I choose to run at varing speeds of 55 and under...I'd be a serious danger to everyone else on the roads. Now, having had enough new cars/trucks in my life plus having built motors before also...the old stay at or under 55 was advised because of not only the load...but the national speed limits. Anyway, I'm sure you've built motors before judging by your profile, and know that when you break in a motor on a dyno...it's normal to exceed 3000 rpms at some times...anyway...back to my original question...is this a driveshaft wobble or what?
Is it consistent with engine speed or vehicle speed? Obviously the driveshaft speeds are proportional to the speed of the vehicle, and not the speed of the engine. It still could be a u joint problem, but hey, with only 250 miles on it, take that thing back to the dealer!!!