Torque Conv. shudder, or something else?

[98EXPY 5-0]

My XPY used to buck like crazy in 3rd and 4th gear (AT). If it got bad enough, my Service Engine light would flash. I was told that was a missfire and I changed the Cooils and plugs. That has 90% gone away. Now, whenever I am driving for more than 20 minutes or so, it will studder and buck a bit. I'm wondering if it's the Torque convertor? No service engine light. I am wondering if I were to kidnap one of the Advance Auto guys and make him ride with me while the OBDII scanner is on, if it will show a fault when it starts bucking?

Not sure how else to figure out what the cause is.

 

[walnuts4x4]

mine did this when I had a COP going bad... no CEL just the bucking..... but I have heard that worn out tranny fluid can cause the tranny to shutter as well...

 

[98EXPY 5-0]

How do I know the difference? On a side note, the local "Pawn" shop had an Actron CP9175 OBDII scanner for $50. Is that a good one that can read pending codes and do all the cool stuff? Or is that just a basic reader that only does the little stuff?

 

[walnuts4x4]

no idea on the scanner... I just have my edge CS.... what I had to do was drive for a while until the CEL came on and then discovered which COP was bad?

Also what type of plugs did you put in? Have read numerous posts on non motorcraft or autolite double platinums causing all sorts of issues...

as for tranny fluid just look at the fluid on the dip stick... or have just the filter changed in the tranny... I wouldn't recommend a flush... can cause many "other" problems

 

[98EXPY 5-0]

I believe I used the Autolites. I know I used one of the recommended brands from the forum.

So you are suggesting a "drop the pan, replace the filter" type fluid change? What is that, like 5 quarts or something? I was thinking that if its the converter, I should drain the converter. But I've always heard that a full fluid change can ruin it.

 

[walnuts4x4]

I've always been told and read that dropping the pan and filter is the way to go... and if you have a drain plug on the converter you can drain that too... even draining the converter your still gonna have a lot of the old fluid in it... cant remember how much but the tranny n converter hold a ton of fluid.. so as long as you don't flush it you should be good... basically mix the old and new because just the new fluid would cause too much pressure to build up on the old seals....

 

[98EXPY 5-0]

Pressure on the old seals huh? I asked my buddy about this (he's a Ford guy, and has a lot of experience working on american vehicles in general). I said that I have always heard that if you replace the old worn out fluid, the tranny will just die. He said that what happens is the components are already worn, but they have like a varnish on them that keeps them going. You remove that varnish and put in clean fluid and suddenly things start to slip.

I know nothing about transmissions, so here is what might be a dumb question. Isn't the torque converter inside the transmission housing? How would I find if it has a drain plug without removing it?

 

[walnuts4x4]

not a big tranny guy myself either just know what I have read and have paid people to do for me...lol... but safest bet would be to drop the pan and let what comes out then drain and change filter and then fill it back up... would only be like changing some of the fluid... somewhere there is a long thread about tranny fluid changes on either here or expedition forum.... i'll have to search later... or hopefully Thermo can chime in here... he is a walking expy library of information....

 

[walnuts4x4]

here is a good thread...

http://fordexpeditionforum.com/showthread.php?t=551&highlight=tranny

 

[98EXPY 5-0]

Ok then, what fluid? A different friend keeps telling me I need Amsoil. Should I add any additives? Like that Lucus stuff?

 

[98EXPY 5-0]

Interesting read. I guess thats the plan. I hope the converter is why it bucks.

 

[98EXPY 5-0]

How much fluid am I looking at for a drop the pan change? I need to make sure my drip pan is big enough.

 

[98EXPY 5-0]

double tap

 

[walnuts4x4]

I wouldn't know last time I had mine serviced I paid a shop...

 

[98EXPY 5-0]

Well I attempted to do this last night. I put one side up on ramps and drained the pan. I went around and cracked all 20 bolts loose. One bolt stayed very tight. I got it spun almost 3 complete turns and it was still as tight as cracking it loose. Not wanting to deal with a stripped hole or broken bolt, I tightened everything back up and just put new fluid in.

I didn't want to get stuck with the pan off trying to deal with another issue while laying inmy driveway up on ramps.

The fluid was so black it looked like I was changing my oil. I got 6.5 qts out of it. I put 4 qts of Mercon V in and started it up to drift it off the ramps and down to a level surface. I ended up adding 1 more Qt so that the dipstick read full. I'll take it for a ride tonight, plus letting it sit for close to 20 hours. I figure I'll be able to get a better reading on the stick. I always hate checking it after adding fluid because I don;t know if I am reading an actual level, or just rubbing the dip stick in the fluid thats left in the tube.


I figure that later I can drop the pan and do it again, and it will still up the ratio of new fluid to old without it being a hige shock to the system.

How often does the fluid in the converter exchange with the rest? I had planned to drain the torque converter as well but since I couldn't finish the job, and didn't have a level surface to work on, I didn't trust putting it in neutral to turn the crankshaft to find the drain.

I was going to add some of that Lucas Stop Slip transmission stuff, but the instructions I followed said not to add ANY additives or cleaners. I've also hear of Ford having an "Anti-shudder" additive, but I've never seen it. Should I have added something? Should I next time when I pull the pan and change the filter?