94 f150 5.0 E4OD 4X4. Hey guys short drive yesterday and noticed I wasn't getting tourqe converter lockup when I should. Then this morning started shifting hard. So I pulled codes and got a 628. In my book there is two definitions, one says cars only. The other,wich I assume applies to my truck is excessive converter clutch slippage. Am I looking at just a new converter or do you guys think I might have more going on. Im just not sure where to start so I thought I would turn to you guys.

 

Ok so when I got back to the shop this afternoon I checked trans fluid I was down alittle over a quart. I reset computer and drove it home and it seems ok,it is only about a 4 mile drive tho. So do you guys think that being a quart low on fluid would cause that converter clutch slippage?

 

It could. It might also be an electrical problem in the wiring between the PCM and the transmission. I would also find out why you were a quart low. Transmissions aren't supposed to lose fluid. If the fluid has more than 10k -15k miles on it, then flush it as well.

 

I do have a small leak not sure where its coming from just yet. I keep an eye on the fluid, I guess it just got away from, me summer is our busy time.

 

Ok guys, truck started shifting hard again yesterday and I got code 628 again. I'm taking it to my buddies shop tomorrow to flush the trans, they have the machine that let's the trans do the pumping. I doubt this will solve my problem but it needs done anyhow. I'm noticing that the truck only does it after its warm. When the truck is cool it shifts great. But once its warm I have noticed that sometimes it doesn't seem to shift like I think it should,especially down into first when going slow up a hill,I have to basically floor it to get first and sometimes it won't shift into first at all, it will just lag in second.but when cold it downshifts into first no problem. It does the same thing trying to go from 3 down to 2 sometimes. You guys think the cheap tps from advanced could be causing all this?

 

I find it odd your not getting the codes for these other problems. I have come to terms with I hate the E4OD. Your not getting any other codes at all?

 

I find it alittle strange too. But no, I'm not getting any other codes. I have been checking codes after every time I drive and its not setting the code until it goes into limp mode. That's why I was wondering if the tps or Mabey mlps could be "working" enough to not throw a code but still be affecting things. I don't know. I love my truck, its in great shape,runs great looks great and is very solid just have this trans problem.

 

The TPS has three positions, C/T, P/T and O/T.
If you put a scanner on it, it will tell you what position the TPS is in as you drive. A code reader has no way to tell you this. You might have to have someone else watch the scanner as you drive.

C/T = Closed Throttle.
P/T = Part Throttle.
O/T = Open Throttle.

 

Thanks sub. Mabey we can hook it up while I'm at my friends shop today and see what's goin on.