Hi All,
First time on site, hope I'm in the right place. I have an older "FedEx" truck that I use for my sign business, great shop truck! 1997, V8/auto, roll up door, folding aluminum shelves, don't know why more contractors don't pick these up. Have had small vibration for a few months, figured a u-joint was on the way out, just got a lot worse. Pulled driveshaft, rear joint was bad so I replaced it. Put it back in, no difference. When this thing shifts into top gear now, and the revs drop, it sets up a "death shudder" that makes you think the drivetrain is going to fall out! Kick it down a gear and the shudder goes away. A friend suggested changing the plugs seeing as these high energy ignition systems load up and take the path of least resistance under load, sounded good, didn't make a difference. 6 out of 8 plugs were however very white (lean). Also, with 2 hands I can feel slight play in front of driveshaft into back of trans, as if the bearing in the extension housing is bad. Anyone run into this problem?
Thanks,
Seann

 

What kind of drivetrain is this truck? pushrod motor/E4OD or modular 4R-something??

One test that I know of is to lightly tap the brakes when the shudder happens, this will unlock the torque converter. If the shudder goes away it is torque converter shudder. The first thing to do is change the transmission fluid. All of it.....16+ quarts. If that does not fix it then you most likely have a bigger issue here.

 

Before you replace that TC try changing your tranny fluid and add a tube of this product:

Dr. Tranny Instant Shudder Fixx

It will stop TC shudder instantly and I have used it many times to correct this issue. It is available at most parts suppliers.

 

I prefer to start with what came from the factory. Using an additive is not my favorite way to go. But it would be worth a shot if the straight transmission fluid method does not completely eliminate the issue.

I do like to hear first hand reports of how those products work for someone!

 

Sorry folks, I totally lost this thread through a computer crash and just realized I had responses to this message from months ago! Anyway, thanks for input. Haven't really used the truck much, but now it's time to fix it. Tapping brakes does stop the shudder (momentarily) so I'm going to service the trans (E40D, Triton 5.4) and throw in some "shudder stopper" and see what happens. Would an "overfull" level also contribute to this problem?
Thanks again,
Seann

 

You don't need that snake oil. Get all the old tranny fluid out and put in some fresh Mercon V. It should go away. If not, you've got a hefty bill waiting.

 

Seann, like the others say don't use that product till a full fluid change of the right stuff fails to fix it. At that point toss it in before you call the trans shop to find out a rebuilt E40D can buy you a nice used car instead.

Over full on anything is sometimes worse then low or empty... IDK on this issue.

 

I had the same issue in my chevy blazer. changed the fluid and filter and that was it. it had about 15K on a rebuilt 700r4 so I knew it was about time anyway because of all the debris that sluffs off during break-in.

I wouldn't use the "shudder stopper" unless the fluid change doesn't work and the only other option is to replace the torque converter. and I'm not sure if an overfull trans would cause your problem but it's not going to help anything, I know that much. if you do go with the shudder stopper drain out some fluid first before adding it.