When I drive my 2000 monte ss in the summer after a while it will start shifting hard. I installed a trans cooler and it helped with the problem but it didnt cure it. I have heard about a pressure control selinoid . Could this be the problem?

over drive shift valve need to be checked. is adjustable on most transmissions. check plug for shift senser

just because you disconnected the shift cable from the trans doesnt mean the car is now out of gear. The interlock switch is located next to the shifter in the center console. Remove the bezel around the shifter and you should see a small tab that reads (shift interlock) pull it out of its holder and the shifter should once again move

trans low on fluid or going bad

I have been hearing a possible solution for this problem is changing the oil filter in the trans oil pan. But ive been looking all over for a solutionand thats the only legit one ive found. It said when the oil gets clogged it doesnt flow to the transmission as nicely as normal therefore leading to lagging changes

try the least expensive option first and flush the trans. make sure its a power flush and the trans cooler gets flushed out. and try an trans additive with the new fluid. 200 bucks is cheaper than 2000 dollars.

it is a skill level 6 to take this out. it is only two hoses and 4 bolts.

If the van shifts ok when cold but hard when hot then the pressure control valve in the trans is bad. When the fluid temp climbs past a certain point the PCS sensor shorts out and stops controlling fluid pressure. This usually causes a whine from the trans (pump) and hard shifting. This is because the PCS can no longer control the pump pressure so the pump now runs at full pressure and shifts as if you were using full thottle all the time - the opposite of what your doing, which is to feather the throttle trying to ease the shift. So now the trans calls for a full pressure shift when your using part throttle and it slams. The (PCS) part is cheap enough but the trans has to be removed to replace it and that's not cheap.

Give this a shot, it often works and it's cheap enough to try.

First, have a good mech carefully check the rediator trans cooler section to be sure there's no leakage of coolant from the enging to the trans coller section of the radiato. This is important!, if antifreeze is leaking into the trans fluid via the cooler it'll cause problems that are otherwise impossible to diagnose and eventually complete trans/torque converter failure.

If there's no radiator problem then power flush the trans and change the filter, then install an aftermarket trans cooler in series with the built in cooler (the instructions with the cooler detail this). It's about $60 for the cooler and maybe one hour to install it.

This whole process will drop the trans fluid temperature 40-50 degrees and often that's enough to get back into a temperature range that will allow the PCS to work reliably again.

If it doesn't work your not out much, if it does work you'll probably get another couple of years out of it.

Al

sounds like a plugged trans cooler.have it checked for proper flow should be less than 10-15psi if so it needs to be replaced. check to see if the trans cooler lines go into the radiator. if so you will either have to replace the radiator (trans cooler is part of radiator) or buy and install an aftermarket cooler

i had the same problem after spending $500.00 for toyota to look at it they didnt fix it and suggested i it was the auto trans and i should get it overhauled costing thousands. i didnt believe them and started to do some of my own research into the problem. the coolant temp sensor at the rear of the intake manifold tells the ecu when the engine is at correct operating temp then allows the auto trans shift into overdrive. to rule out any problems with the auto trans i disconnected the plug to the temp sensor and went for a drive when the engine was cold and it shifted straight away into overdrive no problems. you can't leave this disconnected because the engine is hard to start when cold as the temp sensor also tells the ecu that it is cold and allows the cold start injector to inject more fuel into the engine on cold start up.to overcome this i cut the wire to the sensor plug and installed a switch which i installed into the centre console.now i start the car flick the swith use overdrive then swith back to normal after car has warmed up . engine fault light appers on dash when switched on but doesnt matter. i have had this modification for 2 years now no problems.

You need to rebuild the transmission,it's over heating. May want to check your transmission cooler first .
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