I have an 02' Lincoln Blackwood, (same drivetrain as the Navigator), with 23000 original miles. I recently have had problems with the truck, at fairly regular times but not always, vibrating as I accelerate from 45-50 MPH when it goes into overdrive. It does eventually stop vibrating after a while as I get to higher speeds. It will also tremble as I go up very steep hills at lower speeds of 25-35 MPH. If I drop out of overdrive into 3rd on flat land, it will stop shuddering, (it's as if I'm going over small ripples's in the pavement), or if I'm going up a steep hill, I have to drop it into 2nd for the hesitation to stop. Engine light code of P0174 comes up, ("System too Lean (Bank 2). My guess is that I have a partially clogged injector. Any input would be greatly appreciated, before I take my rig into the "Stealershiup".

 

Under normal acceleration on flat ground when will it start vibrating, -what speed ?

 

If you think it might be an injector, put some good cleaner in the gas - the 2 that work are Techron and Gumout with Regane. Also, change the fuel filter.

It may be a low grade misfire - with only 23k on it I doubt it needs spark plugs, but you may need one or more COP's (coils).

If the transmission fluid has never been changed, after 9 years it would be a very good idea.

A lean code can also be caused by a vacuum leak or an exhaust leak.

 

I guess I had a hard question lol. So far, I think it's the rear end tho.

 

Thanks for the question. Vibration is sporatic, meaning sometimes it starts around 35 mph, other times around 45 mph, but most of the time between 50-60 mph. It will usually stop vibrating when I let off the gas pedal momentarily, then resume my speed. As I stated earlier, down shifting also stops the vibration.

 

Huh, Iduno. Generally, if the rear end friction modifier and/or fluid begins to break down, the vehicle begins to vibrate @ about 45 -55 mph. Feels as tho its coming from the trans, but its the rear end.

It gets worse as time goes on if it isn't taken care of. This will shake the vehicle as well at those speeds.

Everything fits, except for the 35 mph vibration...(?) So I'm not totally convinced that's the problem.

Well, if the fluid has never been changed in the rear end, you may want to start there anyway. It will take aprox 75 miles for the vibration to go away completely after changing the fluid and modifier, IF this is the problem.

 

I think I will do a double wammy & change the tranny & rear differencial fluids this week sometime & report back any results. Thanks guys for these fluid change ideas, as I would probable not have thought of these ideas due too my low milage of 23,000.

 

I had the same thing happen to me only it was my torque converter clutches being worn out, seeing as you said its only 23000 miles that would be surprising and my trans was from a 91 f150 so it was the e40d, but I flushed the trans oil once and it worked like new for a couple thousand then it came back. Just a fyi

 

i have the same problem exactly

i already changed my trans fluid- transfer case fluid and rear end fluid.

im leaning towards either bad TC or Bad COP's or Bad tune

 

Thank you for your input. Can you, or anyone else, please tell me what these two abreviations mean? "bad TC or Bad COP's"

 

TC -Torque Converter
COP - CoilOverPlug

 

Yea, I'm not sure about it being a TC problem, it's possible.

As for a coil. A low grade misfire can occur @ a certain engine load. The most common miss load is at 45 mph right after the shift into Overdrive and under normal acceleration.

What YOU have to do is be able to separate it from a possible engine problem or drive train. I've had both issues in the past. I guess the difference in my case was the shake. A rear end issue will sort of shake vs vibrate. If your unable to narrow it down between the two, it's going to be trial and error. If your fluids can stand to be changed anyway, then it's a good place to start.

 

Thank you for the clairlifications. I'm waiting on my order to arrive of a "Mityvac Fluid Evacuator", (link below), to completely change out the old transmission fluid, along with installing a new filter as a starter.
http://www.northerntool.com/shop/too..._-phone-_-conf

 

ill wait till you change your fluid bigblack and let me know how that goes.

 

That extractor isn't going to get any more fluid out than a pan drop would. The pan holds about 5 quarts, the whole tranny holds about 14.