I know this video is old, but I had to thank you for saving me a ton of grief. I have a 1995 Silverado K1500 with the 4L60E . It developed a brutal 1-2 shift and harsh drive and reverse engagement. I have been a mechanic for 40 years, but have done very little trans. work . I really thought that the trans was shot because it has 250000 miles on the clock. I was also told that by two trans. shops. I was going to drop the pan and check the solenoids and the 1-2 accumulator when I saw your video. My pressure was high also, and it would fluctuate if the pcm was tapped on. So I got a reman pcm for 130 bucks and viola!! Cannot believe how smooth it shifts now! Thanks again for making that video! Saved me 1500 bucks!
I have the same problem in my 95 silverado. Did you buy the new PCM or did you have it rebuilt? Or do you know of a place on the internet where I can buy it?
Good catch. I saw on a Transmission repai help board where one shop had a Suburban with an 4L60E with a hard 1-2 shift, but, the other shift were fine. He didn't say the line pressure, but someone suggested a weak battery would do it. Case solved.
I have circumstantially discovered harsh 1-2s in 2000+ 4L60e vehicles being "cured" by the replacement of weak or undersized batteries in 3 solid instances. Did not diagnose toward this solution, but it makes sense. Many Dodge/Jeep models are known for harsh shift due to EPC voltage caused by bad batt/alt
I need a mechanic like yourself in my area. My 1994 C1500 is running terrible and has a harsh 1-2 shift. I cant diagnose it because I lack the knowledge and experience. I finally took it to a shop and they shrugged their sholders in confusion.
@GaryFerraro The idle will surge on start up and at what seems to be random while driving. It will stumble at stop lights. Sometimes it will miss and sometimes it won't. Also, until it gets out of 1st gear my throttle response is "laggy" for a better lack of terms and will drop RPMs almost like the timing is serverly retarded. I have trouble shooted everything I can think of except my pickup coil, computer, and timing chain. I believe I am having an electronic issue, not mechanical. I am just a shade tree mechanic, though.
If you have a hard 1-2 shift and that's the only bad symptom of transmission....is there any way you could have internal failure and need a rebuild with just that one symptom?
Got a question I have a 4L80E that has zero amps on the pressure control solenoid once you drive 40ft. in gear. It has a new pressure solenoid internal wire harness, and just installed a reman ecu. Prior to replacing the ecu I had to take it on a long drive coasting with the TCC engage before the pressure solenoid goes zero. It shifts real hard. After a key cycle it would read normal 0.88amp and goes to 0.6-0.5amps while shifting. Now with the reman ecu it reads normal 0.8 amps at idle 0.6 while driving in gear. driving to a stop it goes to zero amps. Once I drive it again it shifts hard 1-2,2-3,3-4. I think the reman ecu is bad. Do you know the normal pressure solenoid amp reading while driving. When the issue occurs I can't increase the amps for the pressure control solenoid.
Hello I have 4l60 that was remanufactured I installed it had a hard 1 to 2 hard shift and at times felt like it was sliding into gear I installed a spineless accumulator and Corvette servo it stopped the sliding into gear and at low shifts smooth but when you hit the gas pedal I can still feel the 1to 2 shift not for sure what it is but the rest of shifts are smooth
This my sound like a dumb question but my 1997 GMC Truck well I wanna change my ignition switch and went out and bought one and after taking everything apart the ignition switch in my truck now has a bunch of car alarm wires spliced into it .Im not to good at solicing wires so could i just lay the old ignition switch to the side and hook up the new ignition switch ?And maybe take it later to a car alarm installer and have him splice in my alarm wires.Do you thing this would work?
Great diagnosis Gary! Got a 93 k1500 with the exact same issues. 160 psi line pressure at idle. This one comes to me with a new trans already in it! I have an ancient Matco Interceptor and saw at idle 1.015 amps commanded (20% duty cycle) and an “actual” reading of 1.005-1.015 amps. Getting into the “low” side of the pwm force solenoid at the pcm I measured only 400 mA, which charts out at about 160-180 psi! I even double Checked the pcm grounds for resistance issues and found none. WOW. I hate when my scan tools lie to me! “Actual current” Pffffft….Good find. What do you think causes the low current issue? Weak grounds for the driver inside the PCM. Incorrect programming? Great video.
I have a hard ahift 1-2 but every other shift is smooth and perfect. I don't know where to start in my diagnosis....I guess battery? I need some kind of guide to check off all the things I need to rule out....
Hi Gary. Do you think it's the same diagnosis and cure to my 604 41TE with harsh bump downshift to 2nd, and same with upshift to 3rd or 4th? It has new clutches, shift solenoid, speed sensors, T Position sensor and even the Transgo 604 valve body kit (new seal, expander, springs, corrected plate hole). Thanks.
07 Sierra Classic 5.3 4l60e is shifting rough from 1 to 2 but ONLY when I drive for 30 minutes...thoughts on if its 1-2 solenoid or the trans acc piston???
we have a 01 z71 getting a hard shift 1-2 only when its hot. trying to figure it out, when its cool or cold it does not act up its totally smooth any ideas. no codes.
old school van. Wait wouldn't the g30 normally have a 4l80e in it? normally the 4l60e would be in a lower trim like a g10 or g20. for example the 1992-99 suburban 1500 would have a 4l60e and the 2500 would have a 4l80e. thats odd to me 🤔
lol i know what you mean about people seeing you and coming in. glad the weathers cooler so i can keep the doors shut. ( i know this is 3 years ago but still lol )
I know this video is old, but I had to thank you for saving me a ton of grief. I have a 1995 Silverado K1500 with the 4L60E . It developed a brutal 1-2 shift and harsh drive and reverse engagement. I have been a mechanic for 40 years, but have done very little trans. work . I really thought that the trans was shot because it has 250000 miles on the clock. I was also told that by two trans. shops. I was going to drop the pan and check the solenoids and the 1-2 accumulator when I saw your video. My pressure was high also, and it would fluctuate if the pcm was tapped on. So I got a reman pcm for 130 bucks and viola!! Cannot believe how smooth it shifts now! Thanks again for making that video! Saved me 1500 bucks!
Good Job on getting that fixed
I have the same problem in my 95 silverado. Did you buy the new PCM or did you have it rebuilt? Or do you know of a place on the internet where I can buy it?
or do you think I can change another one of a yunk truck
I believe we bought that from Parts Authority, reman one@@migueltrevino3337
@@GaryFerraro thank you
They brought it to you because you are The Man 👍
Never could have rebuilt my 4T60E without you
Excellent diagnostic skills.
How are there only 200 likes! This guy is solid!
Always great info thanks for the time you take to make videos.
Great diagnosis,Gm usually have computer issues for engine and transmission
This video saved me awesome information
great diagnosis Gary!
Thanks John
Good catch. I saw on a Transmission repai help board where one shop had a Suburban with an 4L60E with a hard 1-2 shift, but, the other shift were fine. He didn't say the line pressure, but someone suggested a weak battery would do it. Case solved.
Thanks for the tip, I have seen bad alternators screw up the shifting, if you don't have the correct voltage at the trans it will not work correctly
@@GaryFerraro mine does the same it will shift hard in 1st to 2nd but all the rest of the gears are perfectly fine
Any Codes
I have circumstantially discovered harsh 1-2s in 2000+ 4L60e vehicles being "cured" by the replacement of weak or undersized batteries in 3 solid instances.
Did not diagnose toward this solution, but it makes sense. Many Dodge/Jeep models are known for harsh shift due to EPC voltage caused by bad batt/alt
@@timothydriggers5312same here did you ever find out what it was causing the hard shifting?
Excellent video.
I need a mechanic like yourself in my area. My 1994 C1500 is running terrible and has a harsh 1-2 shift. I cant diagnose it because I lack the knowledge and experience. I finally took it to a shop and they shrugged their sholders in confusion.
ok, running terrible meaning engine wise?
@GaryFerraro The idle will surge on start up and at what seems to be random while driving. It will stumble at stop lights. Sometimes it will miss and sometimes it won't. Also, until it gets out of 1st gear my throttle response is "laggy" for a better lack of terms and will drop RPMs almost like the timing is serverly retarded. I have trouble shooted everything I can think of except my pickup coil, computer, and timing chain. I believe I am having an electronic issue, not mechanical. I am just a shade tree mechanic, though.
@@megafan0258had the same issue it ended up being the tps
If you have a hard 1-2 shift and that's the only bad symptom of transmission....is there any way you could have internal failure and need a rebuild with just that one symptom?
Great video sharing
Got a question I have a 4L80E that has zero amps on the pressure control solenoid once you drive 40ft. in gear. It has a new pressure solenoid internal wire harness, and just installed a reman ecu. Prior to replacing the ecu I had to take it on a long drive coasting with the TCC engage before the pressure solenoid goes zero. It shifts real hard. After a key cycle it would read normal 0.88amp and goes to 0.6-0.5amps while shifting. Now with the reman ecu it reads normal 0.8 amps at idle 0.6 while driving in gear. driving to a stop it goes to zero amps. Once I drive it again it shifts hard 1-2,2-3,3-4. I think the reman ecu is bad. Do you know the normal pressure solenoid amp reading while driving. When the issue occurs I can't increase the amps for the pressure control solenoid.
Hello I have 4l60 that was remanufactured I installed it had a hard 1 to 2 hard shift and at times felt like it was sliding into gear I installed a spineless accumulator and Corvette servo it stopped the sliding into gear and at low shifts smooth but when you hit the gas pedal I can still feel the 1to 2 shift not for sure what it is but the rest of shifts are smooth
Normal driving is ok?
I have an 03 Silverado with the 4l60e, it only has the 1-2 hard shift after about 40 miles. After it cools down, no problem.
may have an issue in the valvebody
This my sound like a dumb question but my 1997 GMC Truck well I wanna change my ignition switch and went out and bought one and after taking everything apart the ignition switch in my truck now has a bunch of car alarm wires spliced into it .Im not to good at solicing wires so could i just lay the old ignition switch to the side and hook up the new ignition switch ?And maybe take it later to a car alarm installer and have him splice in my alarm wires.Do you thing this would work?
i guess you could but your alarm may not work
Thanks a lot! Gary👍👍👍👍
Thanks for watching
Great diagnosis Gary! Got a 93 k1500 with the exact same issues. 160 psi line pressure at idle. This one comes to me with a new trans already in it! I have an ancient Matco Interceptor and saw at idle 1.015 amps commanded (20% duty cycle) and an “actual” reading of 1.005-1.015 amps. Getting into the “low” side of the pwm force solenoid at the pcm I measured only 400 mA, which charts out at about 160-180 psi! I even double Checked the pcm grounds for resistance issues and found none.
WOW. I hate when my scan tools lie to me! “Actual current” Pffffft….Good find. What do you think causes the low current issue? Weak grounds for the driver inside the PCM. Incorrect programming?
Great video.
its usually a driver
Can I give you a call, does this work for a 2001 silverado
I have a hard ahift 1-2 but every other shift is smooth and perfect. I don't know where to start in my diagnosis....I guess battery? I need some kind of guide to check off all the things I need to rule out....
Hi Gary. Do you think it's the same diagnosis and cure to my 604 41TE with harsh bump downshift to 2nd, and same with upshift to 3rd or 4th? It has new clutches, shift solenoid, speed sensors, T Position sensor and even the Transgo 604 valve body kit (new seal, expander, springs, corrected plate hole). Thanks.
may or may not, what type of scan tool do you have? any codes present for the transmission
A lot of people install a corvette servos into these and report a smoother shifting 1-2 gear. What’s your take on that?
I install everyone and works great, a little while back couldn't get them for a few months but now ok, there back
07 Sierra Classic 5.3 4l60e is shifting rough from 1 to 2 but ONLY when I drive for 30 minutes...thoughts on if its 1-2 solenoid or the trans acc piston???
Would like it scanned for codes, that may give direction
@@GaryFerraro scan code PO894
@@brentlsu ok, that is why it shifts hard on the 1-2. That is a TCC slip code. If you clear it, should shift normal
@Gary Ferraro I cleared it and it did it again. I'm gonna have my friend put it on his scanner which is more fancy than my 80 dollar scanner
thank you GARY
Thanks for watching
we have a 01 z71 getting a hard shift 1-2 only when its hot. trying to figure it out, when its cool or cold it does not act up its totally smooth any ideas. no codes.
Did you ever find out the problem
Having the same issues.
My TCM was faulty. I replaced my TCM and it fixed my hard shifting issue.
Thanks for the Time.!!!
Thanks for watching
old school van. Wait wouldn't the g30 normally have a 4l80e in it? normally the 4l60e would be in a lower trim like a g10 or g20.
for example the 1992-99 suburban 1500 would have a 4l60e and the 2500 would have a 4l80e.
thats odd to me 🤔
I thought it would too with a 5.7 but it did not
Could the prom ever be the problem?
Purchase a computer and still have Same problem.
I think the prom contains the info on the car, i never had that happen@@robertsolis1232
lol i know what you mean about people seeing you and coming in. glad the weathers cooler so i can keep the doors shut. ( i know this is 3 years ago but still lol )
still the same nothing changed
After today's video are they really your competitor Gary???🤔🤔🤔🤨🤨
Shop is maybe 4 miles away from me. I know the manager, i don't really know the owner or who works there
What cause shift only 3rd gear 6R80
sounds like it's in failsafe, scan it to see if codes are present
@@GaryFerraro no code
Completely desmentl inspected ok air pressure with operation ok
@@mubinpanchi2893 did it come in with this problem or after overhaul?
@@GaryFerraro Before overhual same
It went to 270 😵😵😵
what the temp?