Valve Body issue or electrical?

[mcfixstuff]

I have been having issues with my 1994 Explorer the last couple months. The transmission started giving me issues while cruising at 32-45mph. It doesn't want to sit in 4th gear. It either dumps into overdrive from 3rd, or if I put the transmission into OD lockout, the RPM needle will just bounce around, and will give me a very annoying ride while cruising at those speeds. I know the transmission should not be going into overdrive at 950rpm at 35 miles an hour.
I took out the valve body to replace a few parts like the solenoids, and gaskets. When I opened up the valve body, it was immaculate. No gunk, completely clean. The 3-4 solenoid was not the right size, so I just cleaned off the old one with brake cleaner and put everything back together.

The car shifts fine when cold, but once it warms up, it loses its grip on reality between 32-45mph. I am wondering if this is electrical since overdrive is controlled electronically, or if it's still an issue with the valve body.
Anything I can do to test the electrical side of things?
No slippage in any gears during hard acceleration. When entering the freeway, it shifts through all the gears fine, just when I'm cruising I have troubles. I have checked the fluid levels so many times. They are all good. I do have an issue where there's a hard shift from 1-2, and it clunks into reverse and drive, but that has been there forever.
Where do I start. I do not want to try to rebuild the valve body myself. I'll just buy a rebuilt one and slap it in if its either the solenoids or the valve body.

Thanks!

 

[ChildIdenticant]

It doesn't want to sit in 4th gear

4th is OD.

It either dumps into overdrive from 3rd

It's not staying in 3rd?

I put the transmission into OD lockout, the RPM needle will just bounce

OD lockout meaning the selector is on "D"?

When I opened up the valve body, it was immaculate. No gunk, completely clean.

gunk presence is not primary indicator. Lips or galling on the bores/pistons is. If free movement wasn't verified then not much diagnostic value to that inspection.

No slippage in any gears during hard acceleration

Hard acceleration meaning more pedal than normal, or definite WOT?

The car shifts fine when cold, but once it warms up

Estimation of running time/distance traveled before the problem normally occurs? Will it shift fine while cold going up a hill?


All questions aside , the tempurature dependency on the problem , with claim it shifts fine until warmed up, suggests valve body physical/mechanical issue.

 

[mcfixstuff]

4th is OD.



All questions aside , the tempurature dependency on the problem , with claim it shifts fine until warmed up, suggests valve body physical/mechanical issue.

Can you explain why I feel 5 different shifts if 4th is OD? 1-2-3-4-?

Also, to avoid all the hassle of troubleshooting, would you be pretty confident a reman valve body from RockAuto would be the best fix?
I really don't feel like paying someone to diagnose it, which would cost the same as the reman valve body, if just slapping a reman on would fix it.
I'm looking at This one.

 

[MakinJeepsWeep!]

What trans/motor?

 

[mcfixstuff]

What trans/motor?

I didn't realize there were options in the 1st gen. It's an A4LD paired to a 4.0 OHV

 

[ChildIdenticant]

regarding your perception of 5 gears, can't think of an explanation.

1994 Explorer 13 MPG average

I am going to test it, but a year ago, since I was unable to source a decently priced intake hose to replace my broken one I went with one of those "cold air intakes" and I use that term humorously, because there is no cold air being sucked in, to replace the broken hose and it made me delete...

www.explorerforum.com

There you indicated trans issue was solved with fluid level. Changeing fluid can give temporary false positive of fix, just like it appears here.

I can't tell you for sure obviously, but the information across your posts all point to a vb issue, imo.

You don't have to completely disassemble the VB to verify movement. IIRC almost every piston's end can be accessed to push. I used rubber coated dental tools. If any are sticking, then you have much higher faith that the VB is the issue. If nothing sticks, the gaskets are the cost . There is of course the case that the pistons/bores are worn altogether which can't be measured assembled. Much less likely in general though.

You used the correct torque sequence info when reinstalling , right?

Btw, did your hard shifts begin/change shortly after installing the new vacuum modulator (you called it governor, the governor is a different part entirely)? If so , and you replaced with adjustable version, the shift hardness is what that adjuster is for.

If you never found a place that sells VB gaskets, there is a shop local to me that does, transstar. Don't know if they do shipping without a shop account though. I also have 1 or 2 extra I think.

 

[transman304]

The “shift “ you feel is the torque converter clutch locking up. What you are experiencing could be caused by simply adjusting the bands. The front band is 4th. What was the condition of the fluid that was removed?
Brad

 

[mcfixstuff]

The “shift “ you feel is the torque converter clutch locking up. What you are experiencing could be caused by simply adjusting the bands. The front band is 4th. What was the condition of the fluid that was removed?
Brad

I dropped the pan and changed the fluid at 127k miles, when I got the truck. The fluid was dark in a cup, but still red on a finger. Didn't smell awful, and I wouldn't call it neglected. About 142k miles I noticed the constant bouncing between 3-4 and lockup, so I flushed all the fluid. Now all the fluid is brand new. Problem didn't get worse or better. It is the exact same. The main issue I notice is the transmission wanting to go into 4th and lock up at WAY too slow of speeds. 35mph for example, at 950rpm. If I put the shifter to 3 which is labeled as just D, the car will cruise but the rpm needle will bounce and I'll feel it. Almost like it's trying to lock up, but can't because of the selection I'm in.
I have NO idea anything about adjusting bands. Automatic transmissions are foreign to me, so any ability I have to look at something and take a good educated guess at what's wrong, goes out the window when I'm working on the A/T. I had an anxiety attack just looking at the valve body out of the car.
I work part time at AutoZone while I'm paying my way thought college. I don't have much money at all to send it to a shop, which is why I'm asking if my issue will most likely go away with a remanufactured valve body which includes new solenoids, from Rock Auto. If there's instructions on how to check and adjust bands, I can give that a shot, but I just don't want to be stranded and not have a way to get to college or work. I have a motorcycle as a backup, but I injured my knee, and can't start it because it's a 400cc kick start only.

As for the vacuum modulator, I adjusted it to delay longer before shifting, assuming it'll help my transmission from dumping into O/D at 35mph, but it didn't. It did the hard shift between 1st and 2nd before the adjustment, before I replaced the modulator, since I've had the truck.
Also one more note, I'm 99% sure the transmission has been replaced at some point, because I was leaking transmission fluid when I got it, and found the bolts you access from a floor panel under the carpet, were all loose, and one was actually just chilling there on top of the transmission, completely out.

Attached is photos of my valve body in case it offers any clues.

 

[mcfixstuff]

Okay, I'm thinking it's electrical now. Drove around with a multimeter hooked up to the 3-4 solenoid and TCC wire off the ECM. 3-4 Is doing fine. Exactly what the computer wants it to do. When it's in 1-2-3 the voltage reads 13.98. As soon as the voltage goes to 0.24 it shifts to 4th. Voltage does not change when in 4th and TCC is locked. Stable.
Next I tested the TCC wire. At idle, it reads 14.10v. While accelerating from a stop it'll start to dip from 14 to 6.20 volts and fluctuate all over the place in between, when it shifts to second, it pops back up to 13.98 for a second, then goes haywire again. When i'm cruising around 35 and it drops me into overdrive & lock up (the issue i'm having), the voltage is between 2 and 3 volts, still fluctuating. When I'm on the freeway going 55+, the voltage drops to 0.22v when in 4th and lockup (and there never is symptoms cruising on the highway, just city speeds).

Is this a ECM issue? It's not expensive to get a cardone Reman on amazon. Is that voltage reading normal? My hypothesis is that the solenoid is being eratic with the low voltages, and the computer isn't supposed to fluctuate the voltages like that.....but why???

No codes in continuous or normal.

This is telling me the solenoids are doing what they are told.....but where do I go from here?

 

[Nadams01]

Okay, I'm thinking it's electrical now. Drove around with a multimeter hooked up to the 3-4 solenoid and TCC wire off the ECM. 3-4 Is doing fine. Exactly what the computer wants it to do. When it's in 1-2-3 the voltage reads 13.98. As soon as the voltage goes to 0.24 it shifts to 4th. Voltage does not change when in 4th and TCC is locked. Stable.
Next I tested the TCC wire. At idle, it reads 14.10v. While accelerating from a stop it'll start to dip from 14 to 6.20 volts and fluctuate all over the place in between, when it shifts to second, it pops back up to 13.98 for a second, then goes haywire again. When i'm cruising around 35 and it drops me into overdrive & lock up (the issue i'm having), the voltage is between 2 and 3 volts, still fluctuating. When I'm on the freeway going 55+, the voltage drops to 0.22v when in 4th and lockup (and there never is symptoms cruising on the highway, just city speeds).

Is this a ECM issue? It's not expensive to get a cardone Reman on amazon. Is that voltage reading normal? My hypothesis is that the solenoid is being eratic with the low voltages, and the computer isn't supposed to fluctuate the voltages like that.....but why???

No codes in continuous or normal.

This is telling me the solenoids are doing what they are told.....but where do I go from here?

The tcc solenoid has constant power and is wired with the 3 4 shift solenoid. The pcm sends a ground signal when certain parameters are met to lock it. Test the white wire at pin 53 for a ground signal or wire a switch to ground it.

 

[mcfixstuff]

The tcc solenoid has constant power and is wired with the 3 4 shift solenoid. The pcm sends a ground signal when certain parameters are met to lock it. Test the white wire at pin 53 for a ground signal or wire a switch to ground it.

Pin 53 on my 1994 is a Purple/Yellow wire, which matches to the PCM pinout I found here. That was the wire I was using when looking at the TCC signal and getting erratic voltages except for at idle or 55+ cruising.

 

[mcfixstuff]

The tcc solenoid has constant power and is wired with the 3 4 shift solenoid. The pcm sends a ground signal when certain parameters are met to lock it. Test the white wire at pin 53 for a ground signal or wire a switch to ground it.

Is it normal for the voltage to jump around like that, or is it supposed to only be on/off?

 

[MakinJeepsWeep!]

I didn't realize there were options in the 1st gen. It's an A4LD paired to a 4.0 OHV

Thats my bad not paying attention.

 

[ChildIdenticant]

can't start it because it's a 400cc kick start only

Handy knowledge: Key on , apply clutch lever, shift to 2nd. While holding clutch lever get the bike briskly rolling & hop on. Release lever instantly & apply a little throttle. Easy with a twin. Little harder with a thumper.

 

[Nadams01]

Is it normal for the voltage to jump around like that, or is it supposed to only be on/off?

It should have power when the key is on. 12v. Somebody correct me if in wrong but the voltage isn't what is a actuating either solenoid but a ground signal is. If it doesn't have great ground it could jump around as you mentioned. Any wire damage to either solenoid when you had the pan to down?

 

[mcfixstuff]

The issue has been solved in another forum.

Culprit: Frayed wires by the charcoal canister under the hood.

Is the TCC voltage supposed to change when you press the accelerator?

I have been having issues with my TCC locking up WAY too soon while driving. I hooked a multimeter onto the wire for the TCC on the PCM, and when I'm at idle, it stays at 14.04 volts. When I accelerate the voltage starts to drop, once I am over 20mph, it reads around 2-3 volts, and the TCC...

www.explorerforum.com