Hi all. I've posted this in every site I've seen, and also seen many other people with this same problem, but nobody has an answer. After the truck is warm (maybe 10 miles) it will shift hard (into any gear) unless I give it a lot of gas. If I'm in heavy traffic and have to idle along with the flow, when it coast along fast enough to change gears you will feel it (and hear it). My tranny shop owning friend says my tranny is fine, it's the TPS. I've replaced the TPS and it's still doing it. Do I need to unplug my battery to clear the computer? On a budget and hate to keep pouring money into this money pit. Already had the tranny rebuilt twice. I'm ready to swear off Ford.

 

Did your friend actually drove the car with you and tested it while driving around the city?

Unplug your battery for 5 minutes or so should clear your computer.


1. How many years was the tranny fluid been drained?
Tranny is suppose to be drained and tranny filter replaced every 2 years or so. Dropping the tranny pan only removes 1/3 of the tranny fluid. Flushing is also critical. Complete tranny flush is only required for tranny that has been drained and maintained. If the tranny was not maintained and the tranny fluid has already created varnish, flushing the tranny fluid will destroy the tranny because those varnish will break into pieces and clogs and blocks the inside parts of the tranny (tranny's days is already numbered). Most tranny shops that does the tranny flush will use a reverse flow machine and that could do damage to the seals than good. I'd go for a regular normal flow flush machine. However, some folks that has a non-maintained tranny only drain the tranny fluid by only removing the tranny pan and gradually drain the tranny fluid again after 6 months hoping that gradual change will clean and not destroy the tranny.

2. What kind of tranny fluid you have in there?
ATF Type F or ATF+ is used for high friction tranny. Most of our vehicle uses non-high friction tranny and requires the use of Dexron III/Mecron. Some folks have decided to use Type F or ATF+ on their non-high friction tranny to get harder shifting and thinking that it better cleans the tranny and says that is should be alright (I'm not sure about that and why they want it). However, using Dexron III/Mercon on a high friction tranny would slowly trash the tranny.

 

We drove the truck and it actually jerked for the mechanic. He thought it was the TPS, so we went back to the shop and put it on the computer. It showed an irregularity with the TPS. The last time we rebuilt the tranny, I assisted and we took it completely apart. This was slightly over a year ago. However, this is an ongoing problem and was happening long before I had the tranny rebuilt. Just seems to be getting worse now. I known this guy for 30+ years and he is trustworthy. I just hate to pour another $100 into having it serviced and finding nothing wrong.

 

This come up some time ago and I was directed to change the fuel filter. It seemed to stop the jerk shifting on my '92 F150 4.9 A/T. You will need some special tool to get the filter off and expect a gas bath.

 

Thank you. I have already changed this with no effect. Here's a list: Fuel filter, tune up (plugs, wires, rotor, cap), TPS, MAP, cold temp sensor, cleaned throttle chokes good, run all kinds of fuel injector cleaners through the system. Ching, ching, ching go the registers at the parts houses. One place I go the man says he's learning my truck.

 

I guess you have been covering the bases. Mine did the jerking at about 10,000 miles the first time but could never get it to do it until one day we were working on my mechanics cabin and we went to lunch in it and it did it with him in there. It hasn't done it for quite some time and I'm at 158,000 miles. Right now I have power stering fluid dripping pretty good.

 

Thanks for the help. Word to the wise on the power steering pump. Replaced the one in my wife's Taurus earlier this year - new pump blew out the rack and pinion set. Just so much stronger than an old pump, the system can't handle it. Her car is only a '99.

 

I had the same problem, my mechanic made a simple adjustment with the (modulator?) It was a quick easy thing to do, made a world of difference, It still does it occasionally at slow speed when hot. I am debating whether to be greedy and have him adjust a hair more. I also had been told and thought it was the TPS but I was getting no error code, fortunately I met my mechanic lifting weights at the gym. Lucky

 

I just checked with someone about that, but I have overdrive, so I don't have a modulator. Thank you. One of these days somebody will hit on a cure.

 

Check this out:

http://www.dieselinnovations.com/techfiles/sonnax.pdf
https://www.ford-trucks.com/faq/9497...uminstall.php3
http://community.webshots.com/album/25691972abHADDhZFl

I don't know if you have an E4OD but if you do, maybe your friend could install a new accumulator sleeve, valve and valve springs. That may be why it doesn't shift smoothly anymore.

 

Search for threads on MLPS, sounds like it could be your problem.

 

Sounds like your tranny might be going into limp mode...this could be due to heat. Get a hold of a scanner and check to see if it's throwing any codes

 

No codes. Indicated a TPS. I changed that, a little improvement, but not much.

 

I love how people just throw money at a vehicle hoping it'll fix the problem and then complain that it's costing them too much. Diagnose, find the problem, then fix it w/ money. Sounds to me like you rebuilt the transmission when you didn't have to. Find a mechanic that knows how to fix it

I moved this to the tranny forum for ya, I tried to e-mail you but your e-mail is off. I also merged this thread, with the 2nd one you posted

 

Who would you suggest I have diagnose the problem? I have had the codes read at several different places, including a transmission shop. The only thing that ever came up was the TPS, which has been replaced. If you read what others are posting here they haven't had any luck either. One went to the Ford Dealer and they R&R'd his fluid for $100+ and told him if that didn't fix it he'd need to rebuild!?! I'm open to all suggestions. Ford Dealer is willing to hook it up for about $75.00. If he say's I don't know, then what?