1999 F350 7.3 engine cranks and idles fine, but as soon as it is put in reverse, truck dies. Just replaced exhaust backpressure sensor(EVP), and the line from the exhaust manifold to sensor. Know that VSS is bad, but what causes it to die when put into reverse?

 

I assume that you have an automatic transmission, does it do the same when you pull it into low?

 

Yes it is an automatic trans. Yes it does the same when put in low,but fine in drive.

 

I don't have an auto but I do remember something about a short in the wiring to the overdrive switch. Remove the cover from the bottom of the steering column and check there.

 

Will this cause the problem with the truck dying when I put it in reverse?

 

My '97 does this and I read a post here that stating that I needed to change to an updated transmission filter that was released from Ford. My torque converter stays locked up and stalls the engine. I have the E4OD transmission.

 

here is the info on the filter:

Stall when engaging transmission (automatic, usually manual low or reverse):

Torque Converter Clutch.
This may be caused by the TCC being engaged at idle. On trucks built before 9-20-95 the correction is a new transmission front pump and/or torque converter. On trucks built after the above date, it could be cause by a loose transmission filter. In this case, install a flat magnetic strip (from a Tempo ATX or Ranger A4LD transmission) in the trans pan below the filter pick up to retain the filter in place or use an updated filter from Ford that has bumps cast into the plastic to help it stay in place.

 

To give an overview of the problem...
The trouble started when the truck accelerated slow and rough from stop to engine rpm speed 1500. Then the truck would drive as normal. Whenever the truck dropped below 1500 rpms it would shutter in overdrive. As long as it was above 1500 it ran great.
I checked overdrive switch and wiring as suggested. It is fine. I then cranked truck and it ran rough,while in idle, then it smoothed out once it warmed up. I put it in drive and the tach fluctuated between 750 and 1000 rpms. This suggested possible CPS problem. I put truck in reverse and tried to back up and it died.
I pulled up DTC's and got P0340 (CPS) and P0500(VSS) errors. We already knew to replace the VSS .I have now replaced both sensors.
I have dropped the transmission pan and checked for all possible signs of trouble here. Filter is good and no metal in transmission fluid or pan. Gasket is good. My transmission filter is the Ford updated one. Pulled transmission lines for cooler and the bypass line to check for blockage,and found none.I am now putting transmission back together.
Could there be any other cause for this problem?

 

Other people have had posts with the same problem. Shorty after the stalling started to develop the transmission would give out completely and require rebuilding.

 

There was never a TSB on it, but there was a Ford Service broadcast about that issue. Here it is:

Reverse Engagement Stall:
Some trucks with the 4R100 transmission may stall upon shifting into reverse. This is usually caused by the torque converter clutch being engaged at idle. Engineering is investigating. Broadcast Message 1222.
If this condition occurs under cold temperatures only, it may be due to increased viscosity of the ATF. Ford is recommending changing the ATF to synthetic in this case. Broadcast Message 1435.

The problem is there was never anything else that followed it up. I ran synthetic on my last transmission and never a problem. It stays thinner in cold weather, and can take a lot more heat then conventional tranny fluid.
Tranny fluid is basically a 10 weight oil, so when it gets hot it breaks down fast.

I wish I could help more, but this might give you a place to start,

Austin

 

I would like to thank everyone who has responded about my situation. All of these responses have been helpful. I have learned alot through this forum.
I plan to try a Sonnex kit to help with line pressure to T/C to see if this helps. I have not pulled any DTC's pertaining to the transmission at this time, so am trying to identify problem early to avoid complete rebuild. Got truck to run in reverse just no power, also still have shutter between 4th and OD. CPS was bad!!! Thanks again everyone.

 

Synthetic ATF and filter change cured this fault completely for me. Try it before you spend money on anything else.

 

Wow, 10+year old thread. Nice pull.

 

Trying to help those using the search feature. I found some reference to the solution, but no one who had actually done it.

 

Yes sir. I get that, and it is a great thing to do. As these trucks age, we find new and better solutions to problems, it is good to put these with the old solutions too.