I just had my torque converter and solenoid replaced on my '94 E350 RV with a E4OD trans and 98k miles.

Now when at speed (40 to 67 mph) and lightly on the throttle it will skip a beat likes its coming out of gear for a moment then bang back in. It's like running over a 2x4. It's not easy to duplicate but its not going away either. Now I know there are several sensors that could possibly make this happen but why would they act up now?

I should mention that I had the pads and rotors serviced at the same time. When I got the truck back the ABS light was on but it was on before. Seems brighter tho. It did just go out about 40 miles ago and I can't say if my trans has acted up since as I live in the hills and its usually on a long straight slight decline that it does it. It usually is in OD when this happens but doesn't have to be.

The truck is back in the shop waiting on a diagnosis. Will an average code reader tell my mechanic what's happening?

thanks-

 

Do you hear the engine rev higher when this happens? Or does it seem to lose power for an instant?

There isn't much diagnostic capability in a '94. What is available can be read by almost any reader.

 

It happens so fast you can't tell if it revs or not. It just feels like it slips out of gear for 1/4 of a second. At first I thought the engine was missing a beat but its the trans for sure.

 

First thing to do since you're sure it's the trans is to replace the MLPS. It's the sensor on the driver's side of the transmission. Some call it the neutral safety switch.

If that doesn't fix it, you'll need to rebuild the trans. When that doesn't fix it I recommend checking the secondary ignition and maybe replacing the coil, plugs, and wires.

 

Thanks Mark. I wondered about the MLPS just don't believe in coincidence. Why would it go out just when the the TC is replaced? Does the Throttle Positioning Sensor have to be readjusted when a TC job is done? The speed sensor?

The word from the shop today is it was low on fluid. I find that hard to believe it would cause the problem. If it was an issue at full throttle maybe but we're talking at idle or a scant above. They are keeping it for another day or so.

appreciate the help.

 

There is no reason that the MLPS would go out when a TC is replaced. The TPS does not need to be adjusted after a TC job. There is no way to adjust a speed sensor.

I don't see how low trans fluid could cause a misfire, either. And I'm still convinced that's your problem. Let me know if changing parts on the trans fixes your problem. I'm really interested.

 

Interesting that you think it could be a misfire. There are 2 issues that might cause one. One, when I had the work done I had them replace 1 sparkplug I couldn't access- 2nd from the front on the right side. It takes small hands, and an assortment of swivels and extensions. First thing I did was to check that the wire was on well. It is.

The other thing is this engine is prone to manifold warpage. The rear manifold bolt on the right side (again) broke off. I was able to drill and tap it out but the repair is not 100%, more like 93%. There is still some leakage. I recently had the exhaust cones (1st part of the tailpipe) replaced and the muffler shop says it was a common problem due to excessive heat, causing warpage.

If, at light throttle, air was introduced wouldn't it cause a backfire and not a misfire?

thanks for the help. I will find out soon as I'm scheduled to put 400 miles on it at the endof this week.

 

Air in the exhaust won't cause a misfire.

 

Well I got my RV back today after sitting in the shop since Friday. Mechanic says it was a quart low on fluid tho I have my doubts that 1 quart would cause this problem. I'm wondering if the ABS light had more to do with it. We will find out as I'm headed out on a 400 mile round trip.

Mark, what did you mean when you mentioned 'secondary ignition'?

thanks- will post Monday when I return.

C-dad

 

Secondary ignition is the distributor cap, rotor, ignition coil, spark plug wires, and spark plugs.

 

Well the fluid level didn't have much to do with it.

Mechanic changed the TPS today and it seems to have worked. Will put on another 400 miles this weekend and find out for sure.

 

The work done seemed to fix it but not for long. We put 400 miles on the RV this weekend and by the time we got home it was pretty annoying. When we finally got home both my wife and I noticed an odd smell. Trans fluid was leaking on the driveway. There was a line about 125' long at the bottom of the drive running up to where we park. I went to check the level and my beloved mechanic had apparenly broken my last dipstick and welded pieces of 3 sticks together to make one. I couldn't even get it back in to check the level. I cut it off so I at least had a cap.

Out of options here. It gets towed to the not so local Ford dealership asap.

Any tips?

thanks-
C-dad

 

Fortunately the tow driver told me the Ford dealership didn't work on RV's. A quick call confirmed this and it was sent to a transmission shop instead. The rear seal was completely out of the trans and the bushing was beat beyond its life. Shop owner could find no other leaks and said it was from an engine misfire. I knew it needed a tuneup but wanted to sort the trans problem first. So I had him do a complete tuneup (plugs, wires, cap, rotor, pcv & air filter). It didn't fix the trans problem! grrrr.

My thinking is its either something my original mechanic installed (TC,solenoid pack & pump) or something he had to disconnect and reinstall to do the TC job. I picked up a new MLPS and will install it but have to wonder if its not one of the new parts or maybe a computer circuit was damaged by not disconnecting the batteries before doing the work. I'm leaning away from a TPS issue because he didn't need to deal with it on the TC job, or did he?

Again the symptoms are: when at speed (35 to 65mph) and a very light throttle it bangs like its going in and out of gear in 1/4 of a second. On my way home yesterday it did it lightly 5 or 6 times around town and twice quite hard with the OD off.

Any help is appreciated as I've been dealing with this for 2 months now.

thanks-
C-dad

 

Just in case anyone is following this thread the MPLS change didn't solve the problem. I took it on a 200 mile run Wednesday and for 50 miles I was hopeful. I noticed the ABS light had gone off then it started 'bumping' again. The light came back on but went off and the problem didn't go away. I was at a stoplight and it felt like someone bumped into me. Nobody there. It became very annoying in city traffic then climbing a grade close to home I had the OD off and WHAM. It sure feels like it has no idea when to engage or not.

So I called my original mechanic and we discussed it and I told him if he knew what was wrong I'd give him one more shot before I took it to the Ford dealer 65 miles away. Turns out he had taken the trans out and had the second shop, a trans shop, do the work. The same shop that couldn't find the problem or its source. I'm now convinced I have a bad TC or solenoid. What a PITA.