2001 Dodge Ram 1500 5.9L Club cab Lariat.

I have finished my install of the reman long block. Chased a few small problems but otherwise the engine is running great.

Have put about 150 miles on it just driving around town. Today went for a long 200 mile drive. While on the freeway I noticed an audible harmonic starting around 80-85 mph and then goes away as I accelerate to 90 mph. Trying to describe the sound, it’s not constant, but more of a pulse at approximately 2 pulses per second. I wiggle the steering as much as reasonable at 85mph and can get the amplitude of the sound to change a little.

the entire front end was rebuilt: new ball joints, tie rods, tie rod ends, stabilizer bar and strut, new front brakes, new steering gear - all cost an arm and a leg at a local shop.

My tires are Goodyear Wranglers with less than 2500 miles on them. The rims are original but tires/rims have a recent balance.

Can’t feel any vibration through the steering wheel- but the sound is certainly indicative of something wrong.

I’m thinking maybe wheel bearing???

any thoughts? any ideas on how to diagnose?

 

Based on what you've described, I'd assume that your truck is 2WD, unless when you mentioned stabilizer bar, you meant to say "track bar"? Is your truck 2WD or 4WD?

 

It’s a 4WD

new front end parts

• upper and lower ball joints
• 4wd center link
• drag link
• steering dampener
• both tie rods/ends
• track bar
• driver side universal joint at wheel
• rotors and pads

not sure what’s left to replace 😝😩

 

I went through a complete rebuild of the front end of my 4WD truck (all work was done by myself) several years ago due to a random occurrence of "death wobble" not long after I purchased the truck used.

Missing from your front end rebuild are the sealed wheel bearings. Both should be changed, especially if they have never been changed before, given that your truck is 24 years old. It's not at all uncommon for the front 4WD wheel bearing to come apart with high mileage and age. Also, check the front driveshaft U-joints and rear U-joints, too. Is the issue you're having when the truck is in 4WD or 2WD?

 

If you had it apart and one was bad why didn't you replace the other one? And with all those parts the wheel bearings were not replaced?

 

Yeah- well that's the penalty for trusting a professional shop and mechanic to do the job right- when in retrospect I should have done it all myself.

I am thinking the level of effort and skill level required to go back in there and DIY fix/replace the rest of these issues is low/easy compared to the engine swap I just undertook...yes/no? any special tools required? I looked at the shop manual this morning and the procedure doesn't look too complicated

Not driving at 85 mph in 4WD

 

If you've done an engine swap, I'm sure you're up to the task of tackling front end work. YouTube can be your friend here to show you videos of how a particular task is done and whether or not you want to take it on. After I completed a total rebuild of the front end of my truck, I have no fear of driving it down the highway 80+ MPH. Was driving down I-95 Sunday night pulling a 6x10 utility trailer going 80+ MPH in 2WD. No issues whatsoever.

 

The only thing I can think of is large nut on the axle shaft. That has to come off, Depending if the shop went crazy and used a large impact or not that may be an issue getting off. A 1/2 impact may do it but if not, Leave the wheel on and in park(on the ground), Use the socket and a breaker bar or ratchet at least 3/4 inch drive and a piece of pipe for leverage you should have no problem. And IF they where thoughtful mechanics they would have put some never seize on the threads. And be careful when you remove the shaft and be more careful putting it in. You don't want to damage the seal.

 

Every rotating thing will experience harmonics we can detect at a given speed. How often are you at 85 in a 2nd Gen? I'd ignore it.

And yeah, I've done 85 in 4wd in an OBS Ford PSD on I25 S of Colo City, but I agree it's a rare circumstance.

 

You might also want to consider having front and rear drive shafts balanced. Possibly a counter balance came off or if there's rust removing metal or mud adding weight it can throw off the balance. Another factor could be driveshaft u joint angles.