whirring noise above 15 mph after motor swap

[2004exlporer4.0]

I recently swapped a 2004 SOHC for a 1998 SOHC. The 2004 motor blew up from the previous owner and the best block i could find was out of a 1998.

When accelerating i am hearing a whirring noise coming from what sounds to be the front of a 2WD truck. I know that there are a few possibilities as to what the problem is since i only hear the noise when i get past 15mph and it does it during both acceleration and deceleration. The whirring noise is similar to that of driving over a grated bridge or if i were to have knobby tires on, which i do not.

I believe that the transmission is about 2 quarts low on fluid. I will be taking it to get a fluid change tomorrow since i do not have access to a pump.

Is the whirring noise possibly because the 98 SOHC used a different transmission than the 2004? Please note that when doing the swap i put the 2004's flexplate on to the 98's block.

Is it a bad wheel bearing?

Brakes?

Thanks in advance!

 

[Number4]

It's indicative of a wheel bearing. Try driving down a hill that has turns. Turning right will put more weight on the left bearing and v.v.
See if it's more pronounced doing this in one direction.

 

[2004exlporer4.0]

You don't think the transmission would make a whirring noise if it didn't have enough fluid? i am waiting on the trans fill adapter from amazon as we speak so i can top it off since i know for sure it is low several quarts since it slipped on me and then i parked it.

I can eliminate brakes being the whirring because it only does it over a certain speed. If brakes were bad i would hear it the second i started going, right??

 

[anthonymtz]

Interesting, how dose the 98 4.0 run in the 04 explorer? I know that the 98 4.0 v6 only had 160hp @ 4,500rpm while the 04 4.0 had 220hp, dose it feel doggy or sluggish, sorry if I'm off topic but I would like to see some pictures of it!

 

[2004exlporer4.0]

It's indicative of a wheel bearing. Try driving down a hill that has turns. Turning right will put more weight on the left bearing and v.v.
See if it's more pronounced doing this in one direction.

When i turned right i noticed that the sound went away. Straightened it back out and sure enough back comes the whirring. Turn left and it is still there so it only disappears when turning right. Is it safe to say the the right wheel bearing needs to go?

 

[2004exlporer4.0]

Interesting, how dose the 98 4.0 run in the 04 explorer? I know that the 98 4.0 v6 only had 160hp @ 4,500rpm while the 04 4.0 had 220hp, dose it feel doggy or sluggish, sorry if I'm off topic but I would like to see some pictures of it!

No lack of power at all! The thing purrs like a kitten and has the agility of a leopard :exp: I have yet to really pin it because i am still weary of the transmission but it does not leak a drop and gets up to 40 really easy.

 

[rkh58]

Interesting, how dose the 98 4.0 run in the 04 explorer? I know that the 98 4.0 v6 only had 160hp @ 4,500rpm while the 04 4.0 had 220hp, dose it feel doggy or sluggish, sorry if I'm off topic but I would like to see some pictures of it!

The '98 SOHC V6 put out 205 hp @ 5000 rpm as opposed to 210 hp @ 5100 rpm for the '04 version. Your thinking of the OHV V6 that only put out 160 hp.

 

[anthonymtz]

The '98 SOHC V6 put out 205 hp @ 5000 rpm as opposed to 210 hp @ 5100 rpm for the '04 version. Your thinking of the OHV V6 that only put out 160 hp.

Ok gotcha, thanks for the clearing that up!

 

[anthonymtz]

No lack of power at all! The thing purrs like a kitten and has the agility of a leopard :exp: I have yet to really pin it because i am still weary of the transmission but it does not leak a drop and gets up to 40 really easy.

Wow, I'm pretty stoked that a 98 wold work really good in a 2004! Glad it's running good for ya!

 

[4D X]

Its a bummer you had to downgrade to 98 like that but what can ya do sometimes. Keep the best possible oil you can in that thing and keep it clean. I had a backfire in the engine compartment and lost all three timing guides.

 

[2004exlporer4.0]

Thanks everybody for the vote of confidence! This was my first ever motor swap and boy was it fun Aside from the trans being a pest and this annoying whining noise i am very pleased with the motor.

 

[2004exlporer4.0]

When i make a slight right turn the noise completely goes away, then when i straighten it out the whirring or whining comes back. It sounds like i have some big ass swamp tires on it. Is it safe to assume that because the left wheel has more pressure on it that the left wheel bearing is bad. They honestly both need to be replaced but i want the noise gone asap.