My 2006 Ford E250 with the 4.6 (can't remember the trans name/number) is shuddering/stuttering around 35-45 mph more and more consistently lately. Feels like when a clutch starts to slip. Occasionally seems to surge/stutter at higher speeds too when going up a hill, but very slight.
I'm thinking it's the torque converter. I'm of course open to other causes, if you have any ideas.
But if it's the TC...Is there a product that can help with this? If so, what do you recommend?
Sounds like a mild misfire to me
Very common on the AOD and AOD-E to get a lockup shudder at that exact speed. Feels like a light misfire, but the key is that it is under light to moderate load and is speed/gear dependent.
Sounds like snake oil but a good trans additive like BG will clear it right up. Changing the fluid first will help a lot, too. What is happening is the friction properties of the fluid and the slip properties of the clutch linings aren't copacetic anymore, so you need to make the fluid slipperier.
Yep, thanks Pete, that's exactly the behavior.
I had the trans fluid changed almost a year ago, some Valvoline drive in place. Maybe it made things worse, who knows, but it sounds like it is time to do it again and then add some of the BG. Trans is a 4R75E, btw, just looked it up.
Is this the BG product you're referring to?
https://www.bgprod.com/catalog/transmission/bg-atc-plus-automatic-transmission-conditioner/
Yep. Has cured 100% of the shuddering converter issues I have tried it for.
It is funny... Ford 4 speed trans do it at that speed at incipient 4th gear engagement, while Honda 5 speeds do it around 20-25mph. And yeah, feels just like a light miss, but it won't show any misfire counts.
In reply to Pete. (l33t FS) :
Any experience using the BG treatment in Mopar products products that have the 545RFE (like the HC with Hemi) to eliminate TC shudder?
I've had this before and thought transmission. It turned out to be a coil pack (one nearest the front on the driver's side) were coolant from the manifold leaked and caused issues. It started happening only under a heavy load and if you wouldn't give it more throttle to make it downshift. No cel light or anything until it got really really bad.
Thanks Pete. What do you think about me buying the BG treatment and taking it to some lube shop and having them change the fluid and add the product? I don't have the time/space/tools right now to change it myself.
Red91sc, my first thought was coil pack too, but it happens at such a specific speed, and it aligns exactly with what Pete described. If this additive doesn't fix it, I'll look at that coil pack. I do have some coolant consumption going on. Thank you.
I'm also noticing a sort of surging happening when climbing hills with about 50% throttle. The revs will go from like 3k to 3200 and back down again even though the throttle input doesn't change. It's very subtle.
Could this be related to the torque converter too?
Ooooh my 2005 F150 with the 5.4 does exactly the same thing, also at 40-42 mph. It's due for a fluid change so maybe I'll get on that.
Are you familiar with Forscan? You can buy an OBD to USB on Amazon for about $25, then download the free software on your PC .
Read codes, clear , datalog, control certain parameters....very useful for troubleshooting.
Thanks, I didn't know that.
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