Got a 95 F150 5.8 automatic. It shifts hard sometimes. We recently dropped pan and drained converter and blew lines out and installed new fluid and filter and no help. No performance issues or slipping, just a harsh shift especially in lower gears. It shifts smooth sometimes. Any ideas

 

I'm dealing with the same problem right now. Did you pull any codes? Mine is throwing a code 452. Vss signal fault. A vss will cause those problems for sure. I have not figured out where the fault in the signal is yet. But I would start by pulling codes. If you don't know how, use the search function on the forum you should find out how to do it. Also search vss. There is a lot of helpful people here also.

 

I pulled codes since this has been happening and I forget the number but it says something about ABS internal fuse being blown and I forgot to mention that ABS light comes on intermittently

 

Sounds like you read the RABS codes
You need to read the PCM Computer stored codes in Computer Memory (CM).
If you do not know how go to this link below:
Ford Fuel Injection » How To Run a Self-Test

 

I read codes from the PCM but did not write the number down. I have a code reader. I remember the code had something to do with the ABS. I searched the code out on on the internet and read that it has to do with the ABS internal fuse and is not a replaceable fuse it claims. I also read since then that the ABS can mess up the speed sensor which in turn can cause shift problems. I'm just not sure which direction to go with it now. Thanks.

 

Read the codes again and post up the exact numbers.. not the code definitions since those you find on the web are often wrong or misintrepreted.

 

As far as I know there are no codes for the RABS system in the PCM Computer.
The RABS system is not even wired to the PCM Computer so the PCM has no idea what the RABS is doing in our era trucks (198*-1996).

 

I am having a intermittatly (?) shifting problem also. Is it true that the ABS in the rear end can damage or cause false signals from the VSS? I have never had a problem with my speedometer just hard shifts and shifts too soon. Thanks.

Will

 

This transmission is COMPLETELY computer controlled by the same computer the runs the engine, so any sensor issue can and will affect transmission operation.

 

I thought that if the VSS was acting up it would show on the speedo. My speedo has never acted up. I actually have another thread on this, but I was curious about the ABS in the rear end. I replaced rear seals about a month ago and seen the big skinny gear attatched to the ring gear but everything looked ok. My right real seal is still leaking, so I have to get back in there again. Just thought I might know what to look for as far as the shifting problem I have. Thanks

 

in my 94 i was having a problem with it shifting hard and late and i unplugged the tps and that made it shift correctly again

 

Did you replace it or leave it un hooked? I have replaced the TPS 4 times in the last few years. What is really strange is that the CEL does not come on when it is acting up. It only comes on when it is running correctly. Whats up with that!? haha.

 

Where is the TPS? If its easy to unplug it would be worth a try at least

 

I ran the code reader again and strangely enough it did no show any codes at all except 33 which the book for the reader said was verification of the codes being pulled or something like that. I don't wanna replace anything unless I'm sure its bad. Thanks for the replies.

 

SERVICE CODE 33: VERIFY VACUUM IS PRESENT AT EGR VALVE

Service Code 33 in Key On Engine Running indicates that the EVP sensor input did not change after the EVR solenoid was instructed by the processor to open the EGR valve. Because a Code 84 was not received in the Key On Engine Off Self-Test, it is known that the EVR solenoid functions electrically. It is also known that the EVP sensor is in the expected closed valve range because Code 32 and 34 were not received in either Key On Engine Off or Key On Engine Running Tests.

Possible causes:

-- Vacuum hose leaks

-- Obstructed vacuum hose

-- Obstructed EVR solenoid filter

-- Damaged EVR solenoid.

-- Damaged EVP sensor.

-- Damaged EGR valve