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-   -   4L60E Won't start off in drive (https://www.hotrodders.com/forum/4l60e-wont-start-off-drive-506009.html)

ChevyAddict 03-18-2018 08:00 PM

4L60E Won't start off in drive
 
Thanks for any help I get with this to start off. We have been messing with this truck for over a year now and have a problem with the tranny that's confused even our GM cert son in law.

I have a 2000 Tahoe 4x4 with a 4L60E. Last year I lost second gear. So we had our son in law rebuild the tranny. Tranny pan has been dropped a total of 5x this year. The truck keeps throwing a code for the solenoid B being bad. I can drive the truck but I have to start out in second gear. I know that if the B solenoid is bad we would also have no over drive, but I've had overdrive every time. At one point I could put the truck into 4 Lo and reverse and drive would work, but that's stopped working now. I've had it scanned over and over and it always is the same code for the solenoid B. Last time we took the solenoids (all of them) and the harness and had them checked by another mechanic. All of them checked out good. We changed out the PCM with one we know is good, still no luck. So question is what should we look at next? I need to get this fixed. I love this truck and between the tranny problems and the ABS problem I'll be posting about in another post I've had no real problems out of it.

KutzlerTranz 03-19-2018 04:36 PM

Does the code throw as soon as you turn the key on??
Did you swap the solenoids from a to b and try it?
Are the pins Ok on the harness, Or is pin B pushed through?.
Is the wire harness pinched twix the Bell housing/Engine?
Did you reset the spring contacts on the sol plug by prying the contact tighter with a sharp pic??
Did anyone do an ohm check at the computer of that circuit? Positive is your E pin.

As you can see there area lot of questions here. I would pull the plug first and check pins E/A and B against a diagram to verify that the pins exist and the corresponding truck harness pins are in place. Very rare to have connection issues there unless somebody forced something.

If that is ok, Then pull the pan again and clear the codes, swap solenoid plugs (cross connect) and see if your code comes back. If it does,
Then You will need to start looking for internal and external harness issues.

I would suggest putting an ohm meter on the b circuit at the computer end and start manipulating the harness in small sections looking for harness issues were sharp brackets have wore through the insulation.
Reading between the lines, means you are also going to be checking the pin B circuit for shorts to ground also,needing 2 (good) ohm meters.

You should be seeing 20-30 ohms twix E & B And A & E. If in doubt, remember, the A solenoid should be a mirror image of what the B circuit should be.

KutzlerTranz 03-20-2018 10:52 AM

Ok, Reading this over i am guessing you mean that it does not move at all in the overdrive or drive range.
Question #1)
Is this what you are saying??
1) If this be the case, Your input sprag is in backwards, or flipped over. Going into would cause a bind-up if this is the case, Unless the sprag missing.
2)You could be dealing with a forward piston issue. Since these pistons are bonded, and it worked before, its unlikely, unless the sealing ring on the input shaft was cut, then over-run oil would charge both pistons in the second range.
Question #2)
Or are you saying that in the overdrive and drive range, The transmission starts in 3rd ??
Then drops to second, when shifting into manual 2nd, so the vehicle will move easier. (this is normal under a code with the power cut to the E pin)

If the truck does not move in overdrive with the trans unplugged, it is NOT an electrical issue.
If the code is thrown before the vehicle is asked to move, it IS and electrical problem.

You may have Two problems that overlap.
If this is the case, you must fix the 'Code throws in Park' issue first.

Question #3)
What code are you getting & in the definition of the code, does it say,
1) "Circuit" or "Voltage High/Low"
2) "Performance"

Question #4) ??

Is there only one code, and if so, What are the rest, And which code is first on the list?

Transmech 03-28-2018 08:54 PM

You said " I can drive the truck but I have to start out in second gear." Why do you have to start out in 2nd gear?

Answer me this... If you are sitting in the drivers seat, and you start the engine and put the shifter into the D4 position, and take your foot off the brake, will the truck start idling, or creeping forward? Yes, or no? This is the test for a broken input sprag. If it won't move in this manner, the input sprag is broken.

If it will move during this test, does it feel like it might be in 3rd gear? Is that why you are putting it into 2nd? Because it feels like it is dragging on acceleration from a stop?

You say you had a mechanic "check" the solenoids.. Why did you not just replace them BOTH? They are cheap enough..

I'm not quite sure I understand what the problem is. You say you have to start off in 2nd gear.. What is happening that you have to start out in 2nd gear???????? I had to read your post multiple times as it kind of jumps around a lot with irrelevant information that is not pertinent to your issue and is in fact causing me confusion.

ChevyAddict 04-23-2018 09:50 AM

Sorry guy's I'm not meaning to be confusing. This is just new to me.
OHM values have been tested on all solenoids and the internal harness as well. The code does not throw until you try to force it to take off in drive.

"Or are you saying that in the overdrive and drive range, The transmission starts in 3rd ??
Then drops to second, when shifting into manual 2nd, so the vehicle will move easier. (this is normal under a code with the power cut to the E pin)" Is the correct assumption. Once I get it rolling in second I put it in drive and it drives fine until I have to stop, just like the shift solenoid is bad.

The only codes that the truck has are p0775 and P0500 (abs). I've read that the speed sensor on the wheels won't affect the transmission, so I was more worried about the transmission working first. The ABS parts are on the way.

ChevyAddict 04-23-2018 09:55 AM

On another note, this weekend the transmission actually was driving in Drive. After putting the truck in reverse and backing down our long drive in 4L, the transmission decided it was going to drive in Drive, after taking it out of 4L. After driving it for 2 days, however, it's right back to no take off in drive. Could it be something in or on transfer case causing this? Or perhaps the neutral safety switch?

KutzlerTranz 04-25-2018 09:30 AM

I can think of about 273 things that could have been done wrong during the reassembly of your transmission.
There could be multiple mistakes stacked on top of each other.
In all honesty, there comes a time when its best to throw in the towel and start over and seek professional help.

The problem is not electrical. It is internal and unfortunately you may actually have to pay someone to fix it the correct way.

fwiw, I have been fixing transmissions for 40 years and i still make mistakes.
My neighbor kid can read a book for 2 hours and become certified. Its a start but not enough to finish, as your finding out.

I wish you well in your en devour.:)


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