shift feel is hard on the 4L60E because 1-2 is band coming on, 2-3 is band coming off and clutch pack engaging and 4th is band on again. a band will never feel like a clutch pack and vise versa. this is why shift timing is important on the 2-3 shift as there is a lot going on. as well as why it's important to fix 3rd gear leaks as the circuit can easily be starved of oil. this is why we up the pressure, increase shift hole sizes for quicker shifts and fix internal leaks (input shaft to input drum, block both 3-2 valves inboard,etc), it is mandatory on a 4L60E.Thanks for the list, helps with all the guess work . I have a 99 2500 with the 4l80 and it is SMOOTH, but i haven’t considered the swap.
I just figured i couldn’t feel or hear as much of the shift cause it’s a diesel. The 60 shifted great, just didn’t like the continuous in/ out in/ out lock up but after blocking the PWM i was happy with it. And no matter what i did, i could always feel a firmer shift to 3rd ,but it wasn’t a issue just more noticeable than other gears. Maybe the band release? Idk
Are they pretty much the same Internals as far as rebuilding? They the same length or did you have modify the drive shaft? Did you have to get a new/different pcm or can you program your existing one? Or is it as easy as wiring the harness up
And i dunno if i asked, but about my pressure issue, since it’s getting line pressure, wouldn’t that mean the pump is working? I don’t have experience/knowledge in torque converters so i dunno if that could effect anything with my pressure issue or not.
we want to see FULL pressure gives us a good indication that the pump is healthy. as you increase throttle, the engine makes more power (simplified), if you don't get pressure rise then the clutches can't hold because they require more and more clamping force as the rpm increases. once a clutch pack slips, its the beginning of the end. this is why you can nuke a brand new transmission easily: low fluid.
Real easy to make the 4L80E shift firmer: block the 3rd and 4th accumulators with a block off plate. I like the Sonnax LB1 valve here, run the stock 4L80E spring you do not need higher pressure until you get over 700fwhp! you are just making the pump work harder than it needs to and robbing HP. Increase shift holes, don't go crazy on 2nd feed 0.075", 3rd can go .100" range and leave 4th stock, around 0.050". there are a few other (free) things you can do and you don't need to spend $100+ on a Transgo kit...
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