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Discussion Starter #1
Hello everyone,

So your transmission wont shift just like mine well we are gonna figure this out in the next few days. Join me in this troubleshooting thread with some input from a transmission expert from our very own community and anyone else who wants to comment as well. So lets get through this intro and into the troubleshooting.

Ive been having issues with my 4L60E Transmission not shifting. I have Park, Neutral and 1st gear only. Through a few messages with @Tranzman I have some information to give you a base of what we loosely know about my situation.

1. I have no trouble codes or lights on dash besides ABS/ Brake light. (May need a better scan tool for in depth check)
2. My transmission fluid is very low.
3. Disconnected the Transmission from the controller and forced limp mode. Confirmed 3rd and 2nd gear do work.
4. Is definitely not shifting from first though other gears are functioning.
5. VSS(vehicle speed sensor) is functioning.
6. I get up to around 10-15mph @ 3000rpm in first gear.

Now you may be thinking well "Well duh low ATF is the problem or at least part of it" you may be right i just checked it today and it was definitely low. I overfilled it when i got the truck running so i never thought to check it. The transmission is not leaking anywhere i can see but when i bought this truck 6 months ago it had been sitting for 2 years and just recently got the motor rebuilt and the rebuild was not complete so i finished it (not my first rebuild just me and transmission don't get along). I'm thinking the transmission was completely empty, torque converter included that's why its low now even though i overfilled it at first. Also if that is the problem i'm gonna feel really stupid but at least ill know next time.

I got underneath the truck and on the passenger side is a the connector i unplugged to force limp mode. 3rd gear has no torque but 2nd gear will get the truck rolling pretty good. both gears are there but they definitely don't have the low end torque of first gear. So by doing this we confirmed that my transmission is definitely in first gear when in drive but that second and third gear are still working as well even if just in limp mode.

My speedometer is working. Just replaced it like a month ago figured that was the issue cause my speedo wasn't working, might have been part of the issue.

Now for the speed at 3000 rpm was just to check if she was at an optimal speed to shift. at least I think. idk me and transmissions don't get along.

First things first im gonna fill up with ATF and see if i'm that stupid. If that doesn't work then i'm gonna need some help. So for this thread could we assume that the transmission fluid is full and that it just wont shift and all this other information is correct just in case the low ATF isn't the problem.
 

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Randy
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Thanks for the post. It is very hard to diagnose things without some back ground, so thanks again for that as well. To answer a couple of things.
Your statement of "Now for the speed at 3000 rpm was just to check if she was at an optimal speed to shift." That question of RPM & MPH is a qualifying question. It allows someone not able to drive it, to get a feeling of
A) should it be able to shift. minimum throttle 1-2 will happen at 12-15 mph and rpm didn't go over 2000
B) what gear it is really in. 1st @ 3000 = approx 15mph 2nd @ 3000 = 20-24mph 3rd @ 3000 = 30+mph. we have had people that thought it was a specific gear and turns out it was actually another gear altogether.

For transmissions that do not have a visual leak to the ground and are low. Two possibilities come to mind.
A) leaking fluid into the radiator from the internal cooler. this should cause a strawberry milkshake colored coolant.
B) the transmission has a squirt passage from the lube circuit to the rear bushing, so it will not run dry. On 4x4 it shoots the stream of fluid directly at the input seal of the TFC. This is why it has a double lip design. It holds fluid in the transmission and in the TFC. this seal material get very hard after thermal cycling a couple of thousand times. the squirt stream can and does go past the seal and overfills the TFC. A simple fill plug removal will drain excess fluid and tell you where it went.

Transmissions are the only component that use mechanical, hydraulic and electrical all in one. it is also stupid and can only as it is told. The mechanical distress as burned clutches or bad parts throws wrenches in the diag process.

On to the no shift condition. 3 things come to mind, all will need a better quality scan tool to help diagnose.
1) VSS must show a reading in the transmission section of the data base. the computer is capable of using a back up ABS source for speedometer signal.
2) shift solenoid command must show the state change or gear commanded. The solenoid state in each gear is:
1st solenoid A or 1-2 ON/ solenoid B or 2-3 ON
2nd solenoid A or 1-2 OFF/ solenoid B or 2-3 ON
3rd solenoid A or 1-2 OFF/ solenoid B or 2-3 OFF
4th solenoid A or 1-2 ON/ solenoid B or 2-3 OFF
3) the PSM (pressure switch manifold) must show the correct correlation of switch positions to match manual lever position. if it shows 1st for all positions, the computer will command 1st only. this is to big to type out, so I put the two into an attached file.
 

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Randy
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You also stated that the motor was partially rebuilt and you finished it.
Was the motor out?
Could the wire harness be caught, cut or have any loose grounds?
 

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Discussion Starter #4
You also stated that the motor was partially rebuilt and you finished it.
Was the motor out?
Could the wire harness be caught, cut or have any loose grounds?
No the motor was in there. Just needed the transmission to have 3 more bolts put in to hold it to the engine block, spark plugs/wires, exhaust manifolds, and the intake put on. Also rebuilt the vacuum system. Nothing major just the small annoying stuff
 

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Discussion Starter #6
I purchased some more parts today, specifically a Transfer case rebuild kit with new bearings, seals and gaskets
 

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Discussion Starter #7
You also stated that the motor was partially rebuilt and you finished it.
Was the motor out?
Could the wire harness be caught, cut or have any loose grounds?
Ok so I put about 3 quarts In And drove her around the property. She still won’t shift also she keeps eating the oil. She won’t manually shift either (at least when not in limo mode) still. Whenever it gets dry here I’ll get under the truck and pull the fill plug on the transfer case to check if it’s overfilled. I have a rebuild kit for the transfer case on the way rn as well. She bogs down under acceleration but that is probably the OEM fuel filter and pump so I’ll cross that bridge when I get there. Idles fine though
 

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Discussion Starter #8
Ok so I put about 3 quarts In And drove her around the property. She still won’t shift also she keeps eating the oil. She won’t manually shift either (at least when not in limo mode) still. Whenever it gets dry here I’ll get under the truck and pull the fill plug on the transfer case to check if it’s overfilled. I have a rebuild kit for the transfer case on the way rn as well. She bogs down under acceleration but that is probably the OEM fuel filter and pump so I’ll cross that bridge when I get there. Idles fine though
I put 8 quarts in when I first got her running in December
 

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Ok guys im back. i did a little work. put a new alternator on her and a new exhaust last weekend so now she is charging and is getting correct emissions data that she wasnt getting before also she is revving higher, easier. i took her on the road got her up to 30 in first gear still no shift, i let off the gas and she idled down to about 2000 rpm before she fell into 2nd. she didnt slam into 2nd kinda like she just rolled over into it. then as soon as my foot touched the accelerator she downshifted hard. what do you guys think?? another thing. i need to bleed the brakes lol had both feet on the peddle and i was standing on it :ROFLMAO:.
 

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Randy
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How did the scan go? What data can you share?
 

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Is it possible the transmission was new or rebuilt, and didn't have any fluid in it yet? The motor was being rebuilt, maybe the tranny too?
 

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Randy
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If you have been driving it. That scenario seems unlikely. The fact that you have 1st gear tells me that you have power to the solenoids. The computer controls the grounds. So it is not switching the solenoids off. Without scan data, it is anyone's guess.
 

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My mistake. I realized after posting that he said "got it running" or something. It was a long post, and I had assumed that it was being rebuilt, so I thought maybe the transmission was new and dry.
 

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New member here
Hopefully I'm not too late on the end of this post but having something similar here. I'm helping a friend out that has a "99" s-10 with the 4.3, automatic and 4x4. The vehicle had sat for about 6 years then had the fuel pump replaced and a new filter but was still a no start so I told him I'd have a look at it. First off was new plugs, wires, distributor, cap, and new distributor all of which were needed. After that it would start, idle up a bit then slowly idle down until stumbling and dying out. Tried dribbling some fuel into the throat and it seemed pretty healthy then. Replaced the spider injection assembly, and replaced the fuel filter which seemed to help a tiny bit but still had same issue. Further checking the fuel pressure it would go up to about 60psi after a few cycles, then on starting would drop to 40..45 and the engine would die out. Replaced the "new" fuel pump and it seems to run good now. Upon road testing it, the transmission would shift 1st, 2nd. fine then when it should shift into 3rd (around 30 mph) it seems to go into neutral, manually moving the shifter to 2nd it grabs that gear. From what I've been able to come up with the 3-4 solenoid is not acting right but I'm not positive that will cure the issue and don't want to "waste" money if that won't do it. Once warmed up it seems to have a "buck or misfire" just for a half second or so on acceleration but seemed fine when not fully warmed up. Probably 2 separate issues but I'm crossing my fingers to find some help here. Thanks for having this place up by the way.
 

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Discussion Starter #17
New member here
Hopefully I'm not too late on the end of this post but having something similar here. I'm helping a friend out that has a "99" s-10 with the 4.3, automatic and 4x4. The vehicle had sat for about 6 years then had the fuel pump replaced and a new filter but was still a no start so I told him I'd have a look at it. First off was new plugs, wires, distributor, cap, and new distributor all of which were needed. After that it would start, idle up a bit then slowly idle down until stumbling and dying out. Tried dribbling some fuel into the throat and it seemed pretty healthy then. Replaced the spider injection assembly, and replaced the fuel filter which seemed to help a tiny bit but still had same issue. Further checking the fuel pressure it would go up to about 60psi after a few cycles, then on starting would drop to 40..45 and the engine would die out. Replaced the "new" fuel pump and it seems to run good now. Upon road testing it, the transmission would shift 1st, 2nd. fine then when it should shift into 3rd (around 30 mph) it seems to go into neutral, manually moving the shifter to 2nd it grabs that gear. From what I've been able to come up with the 3-4 solenoid is not acting right but I'm not positive that will cure the issue and don't want to "waste" money if that won't do it. Once warmed up it seems to have a "buck or misfire" just for a half second or so on acceleration but seemed fine when not fully warmed up. Probably 2 separate issues but I'm crossing my fingers to find some help here. Thanks for having this place up by the way.
No problem. Put this post up to help similar situations. I told a transmission shop in my town and he said it sounded like my solenoid went out. Haven’t taken it down there. This coronavirus and the flooded oil market are a big part in all this (lost my job) so I haven’t been able to take it to him yet to have him look at it.
 

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Randy
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As a general rule if the vehicle attempts a shift change the solenoids work.
Both solenoids are on for 1st and turn off for 3rd.
3-4 clutch failure is the #1 failure in 4L60E's
 

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As a general rule if the vehicle attempts a shift change the solenoids work.
Both solenoids are on for 1st and turn off for 3rd.
3-4 clutch failure is the #1 failure in 4L60E's
My truck if having the 3-4 shift problem, as well as not going into reverse right away, takes excessive gas to get 1st going then jumps in. Codes said solenoid, random misfires, slipping.... Replaced both solenoids, filter, fluid, changed TFC fluid. Did not fix problem...
 

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Randy
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What codes does it have? Follow the codes, random Missfires have been know to alter the PCM input and lower pressures.
 
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