Been having ongoing issues with my truck ever since the transmission was rebuilt. It is a little irritating. If I take off from a stand still, it will go through first gear just fine, it'll shift into second fine. Then as it gets to the top of the gear, it's like it has a little flutter or kind of a slip. About a 3-400 rpm fluctuation. It seems to be related to what the torque converter is doing. If I'm doing around 40 and step down, it'll downshift and do its thing just fine. But if I floor it, it will downshift and do the flutter once it gets to the top of the gear. But if I gradually step down and don't let it downshift to where the converter unlocks, it will pull hard and not do it's flutter thing. I took it back to them twice already. First time they put high performance springs in the valve bad and thought it fixed it. It didn't. I took it back and they went ahead and rebuilt the trans with a new case just in case in some freak of nature that case was warped. They said it was fixed. Still not. Just been putting up with it for awhile. I'm tired of it again and going to take it back. Just trying to get some insight of what it is doing. New to the group so not sure on how to do everything. But I do have a video of what it does when it does it's thing.

 

I think the first step would be to let folks here know what we're working with as Ford has had quite a few different transmissions through the recent years. Also, was the torque converter replaced...and if so, with what?

 

Sorry. I was in a mood when I posted. It is a 2003 f350 7.3 with a 4wd 4r100. They did indeed replace the torque converter. They put in a triple disc billet converter. Few things about the truck. Has 180/30 full force Injectors. X3 with custom tunes from 1023 diesel. Let me know anything else you need to know. It was $3200 out the door for the full rebuild.

 

Hopefully Mark Kovalsky will chime in...he is the 4R100 guru, retired Ford engineer that specialized in that transmission.

 

I'm not yet retired, but I left Ford in 2007.

The flutter is probably the torque converter locking or attempting to lock. Without data, I can't say for sure.

Quite often problems like this are caused by aftermarket tunes. When I was developing tunes at Ford it took us a year to get everything done properly and tested. It seems to me that the companies that make tunes can crank them out A LOT faster. Are they being as thorough as they need to be?

 

I was beginning to wonder that. I had them revise the tunes ones and still wasn't happy. Their customer service is absolutely terrible. So I did away with that and bought a hydra with customs tunes from Brian Jelich. Having issues getting the chip to work in the truck. But wanted to post here while I figure out what's going on with that. Mark, what info do you need to get an idea.

 

If you watch the desired tc slip numbers for the torque converter and the actual tc slip. While the flutter is happening, the fluctuation in numbers on the actual is consistent with the rpm flutter while driving. If it "slips" the numbers go up, if I grabbed etc etc

 

It would take me weeks working with this and a good data logger to figure out what's going on with the tunes. I don't have the time to invest in that.

 

I completely understand. I didn't know if you had a quick way of knowing what could be going on. But with the info you have been given. Your best bet is the tuner not taking the time to go over everything. And ignoring what I'm telling them with the revisions.
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