I have a 1997 Camaro Z28 with the 4L60E, the trans seems to function as it should except for about a 2 second delay of engagement when shifting into drive. Reverse is fine and all other shifts seem normal. Any suggestion as to what my problem may be would be greatly appreciated. This is the most informative video I have seen, thank you.
This is very fascinating! I got a Reman transmission with 15K on it - and I did a filler tube "flush" of 12 quarts using Dexron VI valvoline and Maxlife. The 15K fluid has a slight burnt smell and I noticed a smoother transmission after the 12 quart "flush" (really a 75% replacement but considering that leaks are the biggest problem (?) - seems like better not to shock the transmission with too much new lubricants!). And what else? I ordered the OEM Magnefine external filter that was made in Australia - it has a better design for both sides of a bigger magnet to grab the in-flow fluid metal - and then a 5 micron fiber filter. And an overflow valve that is better designed. Do you think that is OK - to hook up after the cooler - going back to the transmission? thanks
Richard and Trent at Precision Transmission block the 3-4 accumulator and pwn on every unit they do (given that they also add a z pack and wide band). What is your thought on this?
There are a lot of recipes that builders use in this transmission. I know a lot of builders that block the 3-4 accumulator for better shift feel. I usually don’t mess with it, but I still think it’s a fine modification. Slipping fourth isn’t really a common issue as far as I’m aware. I know many also use the wide band. I’ve used it with great success as well, but now I stick with the borg warner band. I used to use the zpack 3-4, but I’ve went back to the borg frictions. The 3-4 doesn’t fail because of poor friction issues, but for pressure loss. Changing the frictions and steels won’t fix the issue without addressing the leaks. I found some weird 3-4 shifts with the zpack that were cured by going back to oe frictions. Of course, this is all personal preference. If what others do works for them, who am I to say their doing it wrong?
Hi Larry, With most 4L60e's, the 1/2 accumulator, the spring goes in first, then the piston. So you just see the piston when you remove the accumulator housing and the spring lives behind it. The early 4L60e's (1993 and 1994) had the 1/2 accumulator with the piston in first then the spring. With the 3/4 accumulator, the piston goes in first, then the spring. That is the one in the transmission case. With the forward accumulator, the piston goes in first, then the spring. That is in the valve body. Some shift kits have you alter the orientation of the 1/2 and 3/4 accumulator pistons, but if you are putting it back to stock, it should be as I mentioned above.
i have stared and stared at these diagrams. Any guidance on a transmission that wont shift in 4th at all? All other gears shift great. Entire valve body and servo assemblies have been swapped with known good assemblies. Any help will be immensely appreciated.
I would check a few things. 1) use a scan tool to verify that 4th is being commanded. If not, maybe the computer thinks it’s in manual third. 2. If it is commanding fourth, drill and tap a pressure tap fitting on the servo cover and check to see if pressure is getting to the servo piston in forth. If it is, then the servo doesn’t have enough travel to apply the band. If there is no pressure, yet there is a command, it could be a leak in the 4th circuit, gasket covering a spacer plate hole, or a shift valve that didn’t move.
You Sir have a great understanding of these systems, along with a clear and precise way on relaying information. Thank you so much.
Thank you for the kind words!
what a great presentation. Learned so much
I have a 1997 Camaro Z28 with the 4L60E, the trans seems to function as it should except for about a 2 second delay of engagement when shifting into drive. Reverse is fine and all other shifts seem normal. Any suggestion as to what my problem may be would be greatly appreciated. This is the most informative video I have seen, thank you.
Nice Video! Thank you!
Great tutorial ! Thank you for sharing your knowledge and experience.
Amazing video...well done... what are typical steady state and shifting pressures per gear?
Steady states are usually zero. Normal adapts are usually within a few psi of zero, plus or minus
This is very fascinating! I got a Reman transmission with 15K on it - and I did a filler tube "flush" of 12 quarts using Dexron VI valvoline and Maxlife. The 15K fluid has a slight burnt smell and I noticed a smoother transmission after the 12 quart "flush" (really a 75% replacement but considering that leaks are the biggest problem (?) - seems like better not to shock the transmission with too much new lubricants!). And what else? I ordered the OEM Magnefine external filter that was made in Australia - it has a better design for both sides of a bigger magnet to grab the in-flow fluid metal - and then a 5 micron fiber filter. And an overflow valve that is better designed. Do you think that is OK - to hook up after the cooler - going back to the transmission? thanks
Very complicated. I love automatic transmission assemblies!!!!
Richard and Trent at Precision Transmission block the 3-4 accumulator and pwn on every unit they do (given that they also add a z pack and wide band). What is your thought on this?
There are a lot of recipes that builders use in this transmission. I know a lot of builders that block the 3-4 accumulator for better shift feel. I usually don’t mess with it, but I still think it’s a fine modification. Slipping fourth isn’t really a common issue as far as I’m aware. I know many also use the wide band. I’ve used it with great success as well, but now I stick with the borg warner band. I used to use the zpack 3-4, but I’ve went back to the borg frictions. The 3-4 doesn’t fail because of poor friction issues, but for pressure loss. Changing the frictions and steels won’t fix the issue without addressing the leaks. I found some weird 3-4 shifts with the zpack that were cured by going back to oe frictions. Of course, this is all personal preference. If what others do works for them, who am I to say their doing it wrong?
where im getting a little confused is. wheres the accumulator pistons in relationship to the springs?
really great share!!!
larry
Hi Larry, With most 4L60e's, the 1/2 accumulator, the spring goes in first, then the piston. So you just see the piston when you remove the accumulator housing and the spring lives behind it. The early 4L60e's (1993 and 1994) had the 1/2 accumulator with the piston in first then the spring. With the 3/4 accumulator, the piston goes in first, then the spring. That is the one in the transmission case. With the forward accumulator, the piston goes in first, then the spring. That is in the valve body. Some shift kits have you alter the orientation of the 1/2 and 3/4 accumulator pistons, but if you are putting it back to stock, it should be as I mentioned above.
why does the fluid go to the low overrun vale in park? thanks
Can the 4gear be engaged while the transmission is in 1gear to get first gear overdrive in a 4l60e
i have stared and stared at these diagrams. Any guidance on a transmission that wont shift in 4th at all? All other gears shift great. Entire valve body and servo assemblies have been swapped with known good assemblies.
Any help will be immensely appreciated.
I would check a few things. 1) use a scan tool to verify that 4th is being commanded. If not, maybe the computer thinks it’s in manual third. 2. If it is commanding fourth, drill and tap a pressure tap fitting on the servo cover and check to see if pressure is getting to the servo piston in forth. If it is, then the servo doesn’t have enough travel to apply the band. If there is no pressure, yet there is a command, it could be a leak in the 4th circuit, gasket covering a spacer plate hole, or a shift valve that didn’t move.
Excelent informartion
what do you suggest to make work a 95 (PWM) on a 94 (non PWM)
No reverse?
not impressed with the way they did the schematics.. especially the manual valve fluid routing, leaves alot to wonder about.