Hello everyone, Im looking into buying an 85' rx with 139K miles. When idling and revving its great and has no bad symptoms. Once I go into gear and get up to some speed it starts getting really loud (like it revving really high) and sounds like a lawnmower almost. I put it in neutral going downhill and it still made the noise. The original owner said it was a "shuttle valve" problem. She said her mechanic said it was going to require dropping the trans and fixing the valve. The car is great besides this and I really like how it handles. Please advise on what this "shuttle valve" is because Ive done plenty of seaches and havent found anything about transmissions or this valve.



Thanks,

Mick

I dont know of a "shuttle valve" but I know of a "shutter valve" that would give a loud hissing or honking noise if it was to screw up on ya. Do this, pull off the top of your air cleaner and listen to see if its coming from there and get back to me.







-Shawn

Then rip that valve off and replace it with a block off plate.. https://www.nopistons.com/forums/pub...#>/biggrin.png

shutter valve is on top too, its under the carburator. when it gets really bad car will run on one rotor (its a huge vacuum leak)

The Sutter valve is a emissions control system

I took the intake manifold off my 12A, And removed the sutter valve( It looked like a mini choke butterfly) plus yanked the valve's solenoid that was connected to it. I filled the holes with some metal filler.



After that she ran alot better, But I dont have to pass DEQ https://www.nopistons.com/forums/pub...#>/biggrin.png



But I also removed the Air pump, Air control valve and the Port air valve a rats nest of vacuum hoses, andCovered the holes with block off plates..



I dont know about it having anything to do with the tranny.? Do you have a 5 speed or a automatic??

my brother's exhaust sounds exactly like a lawnmower at 2 through 5rpm hehe.



but hes missing a bolt in his header https://www.nopistons.com/forums/pub...R#>/violin.gif

When I got pulled over the first thing the cop said to me was "That thing sounds like a chainsaw! You're gonna fix that, right?"

I put some Supertrapp tips on it so it sounds like a slightly quieter chainsaw. BTW, the shutter valve isn't a problem once you put Webers on it. https://www.nopistons.com/forums/pub...#>/biggrin.png