Yet another E40D Thread

[SOCAL_Redneck]

Why does it always seem like I end up with a truck that has those one off issues no else has had.
So I'll try to make this as short and sweet as possible. I have a 1994 F250 7.3 IDI extended cab 4x4. So when I'm in town or in traffic anywhere from 25-45mph, my transmission acts like it can't decide which gear to stay in. I have no trans or overheat lights on except for my ABS light which sporadically flashes on and off. I can be at 1500rpms cruising, then the truck will shift and jump up in rpms for no reason. There's no hard shifts, just sporadic shifts when I'm in town. You almost can't notice it, but you can see and hear the motor fluctuating rpms and gears. Some more history on the truck, I recently bought it about a month ago. The previous owner had just done some work on it last December 18', one of the upgrades was with the gearbox, which in the invoice they mention the shift points were adjusted. Could that be the source of the sporadic shifts? Also, I almost want to think it could be an issue with the overdrive, but this is only because the overdrive knob is broken and wires not connected. Any suggestions or insight on similar issues would be great.

 

[Slicknik]

It's called hunting , when your trans can't figure out what gear to be in , so it hunts . Had the same issue , does your tach work under 1k? If not there are three item you need to swap,

1. The tach sensor in the motor

2. The speedo sensor in the trans

3 the speed sensor in the diff.

I did 2, 3 and then 1 and I did them one at a time to find the problem , ended up being the tach sensor in the motor, it's location is rt in front of the IP , the wiring runs in the alternator loom so it will make it easier to find . After that my truck shifted 10x better. Also You need to fix that switch, because that throws codes for OD1 by the switch light blinding letrinf you know there is an issue. Cheap fix just get another switch. It also will allow to control when the truck shift into OD and you can shift down for engine breaking as well.

Feel free to message me for further assistance ,

 

[SOCAL_Redneck]

Slicknik thanks for the insight. No tach under 1k, definitely going to check those sensors out and hopefully that's the end of it. There isn't an OD light on, just the ABS light that is flashing. I'll have to pay more attention to it to get the correct code from the blinking pattern. I had just mentioned the OD because the shift knob is broken at the end where you engage the OD. So in the back of my head I was thinking that could be apart of the issue, but from what you explained, I feel the sensors are the main source of the problem. Thanks for the help!!

 

[Slicknik]

Abs light flashing or the e-brake light come on? You may have a vacuum leak in your system, hows your brake pedal? Does it fall to the floor ? Does it sink when sitting at a light? Have you replaced the vacuum Booster? Vacuum pump ? Master cylinder ?

Also no tach under 1k , 1000% replace the sensor in the block first , it's a little expensive, 89$, make sure you take it with you to the auto parts store to match

No need to buy another transmission just needs that sensor , your truck probably shift fine at 1/2 to full throttle but 1/4 throttle it hunts I bet.

Make sure to clean the area around the sensor first because there is a lot of grease build up, also it's a good time to check your wiring to your alternator and clean battery post.

Post a aftermath after you do the sensor swap,

 

[Scooch]

I'd be checking the tach sensor before anything. Pretty cheap part that fixes alot of e4od issues and if you have no rpm reading under 1000 I'd bet money that is part of the problem

 

[trackspeeder]

What you are experiencing is the converter locking and unlocking You will get this often when driving around town.

 

[IDIBRONCO]

What you are experiencing is the converter locking and unlocking You will get this often when driving around town.

That's what I was thinking too. OP, how much change in RPS is there when you see and hear it shift? If it's just a few hundred, then it's probably your torque convertor.

 

[SOCAL_Redneck]

Slicknik The sensor is on the way and yes it shifts perfect 1/2 to full throttle.

I'll have to get back to you on the ABS light, I just put a 4" rough country lift on it. For which I had to go to a specialty shop to get the alignment done, since I got turned down from my local mechanics.

Should have an update come this weekend, thanks for all the help everyone.

 

[LowTech]

I have question on this. I often hear about the tach being an issue. On the trucks it seems like you have a tachometer in the dash, on the early 90's vans we do not. So how does this work for us?
Do we have a sensor and just no gauge?
If so, how would we know if it was bad?

 

[IDIBRONCO]

Do we have a sensor and just no gauge?
If so, how would we know if it was bad?

Yes. Replace it with a known good one. I'm sure that there's other ways to test them. I'm just not aware of them.