VS 4l60e problem

[Portunio]

Hi all,

My VS Stato has got a v6 ectoech with a 4l60e trans, the trans is supposed to be a stage 2 unit fitted with corvette servos.
Over the last two months it started flaring up when shifting from 1st into 2nd, it wasn't too noticable but over the last few days its gotten to the point where it won't shift into 2nd untill 6500rpm - if at all. it also won't select 2nd when kicking down from 3rd, it will kick down to 1st and hold that at redline instead.
Also we don't think its selecting overdrive under load, at 100kph on the freeway, with the shifter in 4th position, it will sit at about 2800rpm on throttle. But off throttle if you move the selector from 4th into 3rd and back again there is a noticable drop in rpm.
We checked the fluid level and its ok, but the fluid in the trans is black.
We were thinking of changing the shift solenoids and changing the trans filter and re-filling it with fresh oil but we aren't confident that will solve the issue. Has anyone got any thoughts as to what the issue might be, or any tests we can perform before spending a whole bunch of money just on a guess?

Thanks,
Marty

[The1]

if the oil is black most likely the damage is done, i would have been looking at it when it started slipping 2 months ago. If it has a shift kit in it, then the pressure will be increased and with the forward accumulator on alot of 4L60e's being plastic it gets brittle and either sticks in the bore of the valve body or cracks and leaks, this supplyies the forward clutches with fluid and pressure so once this goes then the everything starts to slip and if not fixed straight away then damage will be done, it's a $10 part to and GM servicing says it should be replaced or new seals applied to it every 80,000KM. How does it go changing from Drive into Reverse? Sloppy?

Your highway issue sounds like the Torque converter isn't locking up which will drop the revs from that to about 1500rpm which could be the solenoid or TCC itself worn out.