I have a 1995 pontiac bonnevillie ssei the car wont go over 45mph its like the tranny gos into netrual then the rpms go up till i let off the gas.i checked the tranny fluid its good.as soon as you get under 40 mph the car will take off again till it hits 45 mph.and i need a dirgram of the relays under the hood on the firewall i think there is 8 of them i dont know what they work.thanks

Based on the symptoms, I would think its a torque converter problem.

I hope its not that!!!

There are lots of things that will prevent your car from going over 45, but your description of it feeling like the trans goes into neutral and engine revs up sounds like a torque convertor to me as well.

I'm not getting how that'* a torque converter.

A torque converter works with rpm in all gears. If you are getting to 45mph then you have at least first and probably second and or third, unless you are revving very high to reach 45mph.

If the torque converter was starved for fluid, that should also occur in all gears.

How many miles on the transmission?
When was the last filter/fluid service?

Definitely not a TC issue. The TC is always going, as long as the engine is turning. The only thing that ever changes in the TC is the lock up at a certain speed. Even if it failed to lock up, you would still get forward motion, just at a slightly higher rpm than if it had locked.

Does it just hit 45, then the rpms go up without the road speed going up?
Have you tried manually putting it in 2nd, and see how it behaves?
Try driving in manual 2nd, and then keeping it in manual 3rd (if that'* an option), just don't put it in OD.
If you're hitting this "wall" at 45, and the rpms jump up, the trans isn't going into the next gear. Depending on how hard you are accelerating, that could be 3rd or maybe OD.

Did this suddenly happen, or has it been getting worse over time?

The car did this once before for a mile then stopped.the car will light the tires up but as soon as you hit 45 thats it.now when you hit 45 if you crack down on the gas it will hit 80 mph.the tranny was put in 3 months ago the fluid is fine nice color..could it be a relay.i need to know what the 7 relays are on the firewall i need a dirgram.my fans aint kicken on now sence this happened

The rpms stay normal when speeding up to 45 mph but if you crack the gas down it will speed up past 45 mph

If you move the shifter from OD to D, does the car operate OK?

Its about the same.the tranny shop said its something eltronic