GM 4L60E - No Forward or Reverse when HOT

[@viclopez3365]

Thank you Robert, awesome video, I’m so glad I came across this informative bit of knowledge. Keep them coming man, I’m in the process of tearing into my 16 year old son’s 2005 trailblazer, his first car and see what the problem is. It does exactly what you described, only it happens in less than 5 minutes of running time in the yard just moving it around. Thanks again

[@bennyconas6556]

Hey let me know what u find. I'm having the same issue and it's out of a 04 trailblazer also. 🙏

[@SouthpawAutoworks]

Father son time... Right on!

[@rpridgen]

Hey there Robert First off I want to thank you so very much for your videos on KZbin. I’m one of your subscribers and I’ve run into a problem with my 4L60e. I rebuilt it a few months ago and it seems to be a little sluggish in 1st gear as if it’s slipping. All other gears pull/shift as they should but starting off just isn’t the same as it was. I’ve pulled it back out 3 different times chasing other issues and rechecked all clearances (all to factory specifications). So far Parts replaced: All steels and frictions Seals Plastic accumulators upgraded to aluminum Molded pistons Low roller clutch (sprag) Forward sprag Torque converter Input drum (27 spline) Bushings Pump body and cover (complete) including 13 vein rotor and slide Boost valve (stock new) Transgo drop-in Pressure regulator valve 3rd gear check ball capsule (servo bore) Rebuilt valve body Line pressure: 60-65 at idle Pressure boost at shift is approx 180-190 After shift approx 90 then dropping to 60psi Reverse 90-120 Sharp spike with throttle blip in gear 60-120 All specs are verified through the ATSG book. Any ideas on why it’s acting like this? I was kinda thinking it was a bad torque converter but reverse is as normal as it was before…I’m at a loss…. Out of all the people I’ve seen and researched on KZbin by far I’m sure you’re the most knowledgeable person about the 4L60e. I know you’re very busy and I appreciate and value any info of your thoughts of what might be going on with this….it’s driving me crazy! Ha

[@SouthpawAutoworks]

New rebuild...right on. Appreciate all of the detailed info you've provided. When you say sluggish, it has me thinking it's possibly starting off in the wrong gear (2nd gear start). You also mention "as if it's slipping." Is it in fact slipping? Are the RPM's jumping up, as though it's going to neutral?

[@rpridgen]

@@SouthpawAutoworks yes…it seems the rpm’s are higher than normal for 1st gear to begin movement and then again it seems like it’s working hard to get going like the wrong gear. But, it will creep on its own from a dead stop when you release the brake. Do you think it could be the band dragging on the reverse drum? I did notice the servo didn’t have a lot of movement in and out (inside if the bore/w retaining clip) when I installed but it air checked good and I was able to rotate the assembly (reverse/input drum) with no issues at rest (no air applied). It does seem like 2nd gear…after shifting it’s all normal. Sometimes the shift can feel a little harsh but not all the time. I do have a video of the pressures while driving if that could help. I’ll post it on my channel so you can see it if you have time to check it out. Thank you again for your help…you’re the best in my book!

[@bennyconas6556]

Thanks Robert if the filter doesn't work ill swap out the pressure switch then the pump then the torque converter. All fails im getting another core lol

[@michaelthul6013]

I learned a thing or two on this one , Thank you for passing on your knowledge.

[@SouthpawAutoworks]

You bet!

[@JiggaJ1979]

Appreciate it, mine did the same thing the filter seems to have done the trick 🤞

[@richardlewis4288]

Awesome info!

[@SouthpawAutoworks]

Thanks for watching!

[@mikemanson6872]

What do you think of no reverse when the transmission gets warm? All other gears are not affected and all shifts are fine and smooth. Reverse works fine when I first start it up. Then gets to running temps and it’s gone. This warmer weather we have makes it worse too. Thanks in advance

[@vazfx16]

Great video. Thank you

[@SouthpawAutoworks]

You bet.

[@jcaleca60]

This is why I changed my transmission fluid every 30000 miles. Regardless of what the manual says.😮😊

[@SouthpawAutoworks]

Preventative maintenance is the way to go.

[@jcaleca60]

@SouthpawAutoworks yes

[@ferny6.0]

I got a question. I have a 2007 4L 60 E. All my gears shift perfectly fine. When my transmission is cold, reverse works but when it gets hot, it don’t engage

[@DustinKeating-yk3vq]

I changed my filter the other day and i was able to get 5 quarts of old fluid out my transmission so i replaced rhe 5 quarts but my transmission holds 11 quarts so i used my truck for a few days then i pumped my pan out and replaced with new fluid but it still looks dirty but im going to keep pumping the pan every few days and replace with new fluid and eventually it should start looking clean what you think about this what im doing

[@raystanton238]

For those that are just learning, that transmission is sitting upside down on that work bench.

[@SouthpawAutoworks]

LOL

[@remingtonlangworthy2511]

Whats your take on no 1st no 4th. no codes. I usually have to replace the pump to get 1st and 4th back.

[@SouthpawAutoworks]

Has me thinking... 1). Potential issue with the solenoid (bad valve seat, cracked snout, etc). 2). AFL valve. The same oil pressure that's used to stroke the 1-2 shift valve also strokes the 3-4 shift valve. It's called 1-2 signal oil pressure. If the there's a problem with this oil circuit, it will affect both shift valves. The AFL valve supplies the signal oil pressure. Check out these videos to learn more. 4L60E AFL Valve - How it Works: kzbin.info/www/bejne/gqKlnJebnLWdhM0 4L60E Shift Solenoid - How it Works: kzbin.info/www/bejne/fJKmmYqjmNh0nas 4L60E Shift Valve - How it Works: 1-2 Shift Valve: kzbin.info/www/bejne/oIHLnmpsh6mtbLs

[@frankdatank7751]

​@@SouthpawAutoworksWow, good explenation!!

[@SouthpawAutoworks]

Appreciate your comment.

[@jeffkovene4420]

Only reverse is inoperable upon heating up? What could this be?

[@m3talc0re]

What about the opposite? My trans will shift 1-2 when I leave the house, but refuses to shift 2-3 until maybe 4 miles or so from the house after coasting downhill for like 10 seconds with my foot off the gas. Then it will finally shift up into 3rd, sometimes. It will downshift while passing someone or going uphill fast, but won’t shift up to 3rd (or 4th? Not sure) until I’ve crested the hill and take my foot off the gas for a minute to let the rpm lower. Any ideas? This has been driving me nuts.

[@vadimnesen8060]

Put some strong magnets on the oil pan and your good.. for a little

[@mr2times68]

So in my case it makes sense with having an oil leak smh thanks for the information

[@jonjacson13579]

i have a 2001 s10 have all gears except reverse reverse works until warm