Hi all,
I have a 4L60E in my 1995 S10 4.3 CPI V-6 truck with 62K original miles on it since we bought it new. I am doing some maintance work and upgrades to the transmission because the fluid needed changing and it needed a new dipstick and tube with seal. So far i have pulled the valve body and have it completely disassembled and cleaned. Im looking to keep it stock to get the longest life out of it but i want to address some of the problem areas now that i have it apart. Let me know if these are good ideas to do:

New GM Dipstick Tube and Lower Seal and Dipstick Indicator

Sonnax .490 Boost valve without O-rings

Sonnax TCC Apply Valve in pump part#77805E-K

Unknown brand O-ringed Valve to put in Valve body to convert to On/Off style Lock Up see attached picture to see the valve itself. Transgo has a valve called ISO CONV on/off valve, is this a better valve?

Transgo separtor plate and gaskets (my original plate has some rust on it so need to replace) also, do i need to drill larger holes in the new plate under the filter screens if i use the .490 boost valve?

Sonnax Heavy Duty 2-3 Shift Valve part#77754-41 applies overrun clutches in 1st and 2nd also not just 3rd like OEM. is this a good idea?

Also can i cure these other 2 problems while im here? :

There is a 2-3 upshift clunk during light throttle upshifts, or when I get on the gas in 2nd and let off and it clunks into 3rd.

And there is a 2-1 downshift clunk into first when going uphill under very light throttle and as the truck slows down it will clunk into first gear.

Also, how can i test the EPC Force motor Solenoid to see if it works properly?

Thanks so much

 

More holding pressure/force in any gear is a good idea. I've never looked at that valve, mostly because I'm all about doing things on a bidget I suppose. It looks like you are doing just about every modification under the sun for the valve body. I'd recommend replacing an accumulator piston or two. I noticed they make pinless ones. I've seen one trans fail from one that wore out and I'm suspecting my cousin is having problems from his as well. These are HIGH mileage transmissions though BTW... 200K+

Have you looked at the transmission mount as a cause of the clunk? Not many miles on the truck, but you can't always rule it out. The only other thing that is moving in all those instances is the 2-4 apply band. You may not notice when it releases from 4th-3rd because there is enough road or engine noise to cancel it out. Or can you actually feel the clunk?

EPC Force motor Solenoid? I'm guessing you are talking about the solonoid that controls line pressure for transmission fluid apply circuits? I don't think there is a way to check it. When I rebuilt mine I put 12V to it which was probably not a good thing because it sounds like it's either pulse width modulated like the torque converter control solonoid or something else.
I put up a post where I listed at least 4-6 engine sensors that affect the operation of this solonoid and how it affects line pressure and shift feel.