Trans shudders shifting into 3rd gear from 4th

[91stranger]

So here is what happens sometimes. Not every time but sometime. When driving down the road at 50-55 and hit a slight hill instead of shifting smoothly into 3rd gear it shudders a little then goes into 3rd gear. Now if I let off the gas and hammer down it doesn't do this. Anyone know what could be causing this? Its a 1999 3.0 liter auto trans with 99,800 miles with tow package. Just got it a month ago and didn't do it then (from my knowledge). Is this easy to fix? I'm pretty good with tools and can fix most issues I run across just need to get this diag'd first. I've heard everything from speed sensors to bad trans fluid, to bad trans filter. I don't have the money to put into it for a maybe fix. Any help would be nice. Thanks.

 

[ratdude747]

Sounds like either a failing 3rd gear clutch or a bad seal in the valve body. Seems like it's following transmission pressure.

 

[91stranger]

But if it was a failing gear clutch then wouldn't it happen more often? it doesn't do it all the time so that's why its got me confused. Really thinking its a sensor of some sort. Could it just be time to change the fluid in the trans?

 

[cbxer55]

Mine has done this for several years. I recently changed both the fluid and filter, and it still does it occasionally. Doesn't seem to hurt anything, and as you say, when it does if you hit the gas, it goes away. Doesn't really bother me either, not enough to tear it all apart and try to figure out what causes it.

I've had the truck 17 years, my sister had it four and really tore it up. It's my all weather beater truck now. I try and keep up with it, but in the end, if something major happens, it's off to a scrap yard. It's got many hail dents, ac doesn't work (not worth fixing at this point), front end needs to be replaced (not worth fixing at this point), and looks like hell. Never loan a vehicle to a female family member. She drove it for 4 years and 40,000 miles, didn't wash it, clean the interior, or even change the oil.

 

[Denisefwd93]

Mine shudders when I let off the brake, slams while in gear sometimes, when on a slght hill sometimes slams 2nd to 3rd, been doing it for 2 years now. In storag, I have an M5OD and 4.0 out of a 98 donor that had 62k on the od. Just a matter of when not if.

 

[ratdude747]

But if it was a failing gear clutch then wouldn't it happen more often? it doesn't do it all the time so that's why its got me confused. Really thinking its a sensor of some sort. Could it just be time to change the fluid in the trans?

Not if it was just starting to go out. But I'm not a transmission expert.

If it were a sensor I'd think you'd get a flashing tranny light?

---

I used to drive a 1995 3.0 (which was wrecked and replaced with my current 4.0). Only time it shuddered was when I bought it, and that (and many other issues) were due a shot tranny with bad clutches and bands. I ended up getting a rebuild done on it which fixed the issue (minus a drainback problem after I did a routine fluid change 2 years later).

Do also know that the stock separator plates (sealing device between tranny case and valve body) were known to blow out and were superseeded by an updated part from Ford. Not saying that's the problem (if it was,you'd have bombed a gear much more obviously), but it is a known issue.

Finally, if memory serves one reason they went to mercon V in 1997 was torque converter shuddering. Did you change fluids recently and use dex/merc insteat of mercon V? Although if your fluid is old AND burnt/gritty you're better off not changing as you will probably kill your seals (and since the damage is done, might as well get more life out of it since a rebuild is a rebuild).

 

[cbxer55]

My truck is 19 years old, and I've had it for 17 years. I've changed the tranny fluid twice in that time, 2009 and this year. This year also did the filter. Fluid never had a burnt look or gritty feel.

To the OP's problem, as I said earlier, mine does it as well. Earlier I said changing the fluid and filter didn't make a difference. I was talkin out my azz. It doesn't do it nearly as much as it did prior to the fluid/filter change. So it does make a difference. Might want to try it just to see.

I did the fluid/filter change back in January, and to my recollection, I've only felt what the OP refers to twice since then. And yes, Mercon V was used. That's all I keep in my garage since my 2004 Lightning uses it, and I changed that back in 2013.

 

[91stranger]

Thanks for all the advice. For now I got other issues that need fixing like my rear shackle just broke and I'm leaking gas when I'm filling up. Tried adding some gas safe sealant around the filler neck and that just made it worse. Now I can only put about 10-20 cents of gas in before it shuts off like its full. Must have blocked the screen or something. I think for now I am just going to leave it. Maybe add some Lucas to the transmission and see. Like I said it doesn't do it every time or all the time. Just when I'm on hills and it goes to shift out of 4th gear into 3rd gear at a low speed. Doesn't do it al all if I'm pedal to the metal.

 

[cbxer55]

Just for fun, have you ever tried just hitting the OD button and turning OD off before the computer tells the transmission to do so. I mostly do it all the time. I even use the shift lever and downshift out of 3rd into 2nd when coasting down to stops. Saves the brake pads. My factory rear brake pads lasted 19 years, still had material on them when I changed them. Fronts lasted 16.

Next time you're headed up a hill, turn the OD off earlier than normal, see if it does the same thing when you manually shift it out of OD. My feeling is that the computer waits too long to make that shift, and the engine bogs down after doing so. I find the 3.0 more fun to drive when you keep the rpm's up, keep it in it's powerband.

 

[Broo]

A bit late to the party, I had a similar shudder happening for 5th gear last year and fixed it, or at least reduced it to a point where I don't even notice it :

http://www.therangerstation.com/forums/showthread.php?t=170235

 

[91stranger]

Haven't noticed it doing it lately. Not sure if I just know when it's going to happen to avoid it doing it. Was never a serious issue just annoying. I like to fix problems before they get fubar. Thanks for the advice but I'm just gonna let it be for now.