02 Explorer 4.0 Hard Shudder

[Willybobo]

Hi everyone. My 02 Explorer 4.0 has a hard shudder that occurs between 1,500-2,000 RPM. It occurs when I am in light throttle and when it occurs I have to give it more throttle to kind of "push it past it" I should say. The issue is more likely to happen when going uphill or when having the throttle at a steady speed. As this begins to happen you can hear a weird distinct noise that continues throughout the shudder. There is a link so you can see it for yourself(I suck as describing issues). Other than that it drives very well and shifts smooth as far as I can tell.

I have done some research and these are some solutions I have found.
New Spark Plugs and Wires(Done Already)
Fuel Filter?
Fuel Pump Relay?
Fuel Pressure Regulator Leaking into vacuum hose?
Dirty MAF Sensor?
Viscosity of transmission fluid?(I read about changing the fluid and cleaning the pan, also I read about adding this Friction Modifier to my fluid?)
Problem with the torque converter?

I want to throw fixes at this issue and waste my money so that is why I am here asking for your input.

What do you guys think?

 

[Willybobo]

Anyone have any takes on this?

 

[Number4]

May be a misfire. Was for me. Need to read live data to see if it is. Won't get a check engine light until you've had 1,000 misfires.

Get Forscan and you'll be able to tell.

 

[Willybobo]

A friend of mine hooked up it up while we were driving and it did not read any misfires.

Any other suggestions?

 

[Number4]

What did he use to read misfires?

 

[Drewmcg]

if it only happens while moving (under load), it sounds like a trans (or torque converter) problem. try repeating with the overdrive button turned off (pressed). the lockup is in the t.c., i believe.

 

[Willybobo]

What did he use to read misfires?

I am unsure of exactly what he used but I know he was reading them while we were moving.

if it only happens while moving (under load), it sounds like a trans (or torque converter) problem. try repeating with the overdrive button turned off (pressed). the lockup is in the t.c., i believe.

This is what I'm leaning more towards based on my research.. How can I go about further diagnosing this?

 

[Drewmcg]

There are torque converter PIDS that a good mechanic or trans shop might be able to diagnose with scan tool to give some insight. I swapped my torque converter when pulling a lower-mileage 4.0 SOHC motor to install in my '02 XLS after researching t.c. problems. T.c.'s are pretty reliable but there's a lot going on in there, and of course you can only replace them with either the engine or the trans pulled. I also pulled the pump (at front of case, "behind" the t.c.), which was trickier, but allowed me to upgrade a flow valve that sits in the pump whose original design reportedly has had some issues.

I'm not a trans guy, though. For example, I do not know whether the solenoid pack (accessible w/o pulling trans, sits above the trans fluid pan) might relate to your problem. There are PIDS on the solenoids accessible via the scan tool, too. I also replaced my trans solenoid pack with the lower-mileage unit since these are reported to sometimes have problems, and I was drop;ing the pan to replace fluid and filter, clean the magnet, anyways.

Bottom line: A good trans shop can do a fuller diagnosis. Start with http://www.atra.com/, and then use yelp/google reviews to find a reputable shop.

Whether a fluid change could help/mitigate the problem, I don't know--but it would be a relatively inexpensive thing to do, especially if you have more than 150k miles and have not done this before. Good luck.