cjac Posted December 16, 2015 Share Posted December 16, 2015 I have a high pitched whistle sound when traveling down the road. When I let off the gas it stops, get back on the gas the noise comes back. I've checked u-joints and seem to be ok but can lube them. Vacuum line under hood are good. Don't know what else I can check. Quote Link to comment Share on other sites More sharing options...
centralman Posted December 16, 2015 Share Posted December 16, 2015 Have you tried running your car on idle, then simulate pressing the gas by pulling the throttle cable and see if the noise exist? If it does, may indicate a leak in the intake system. Quote Link to comment Share on other sites More sharing options...
shibs Posted December 16, 2015 Share Posted December 16, 2015 belt slipping, check the tension on the belts. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted December 16, 2015 Share Posted December 16, 2015 Though belts can certainly make a noise when slipping, I know that I wouldn't use the words 'high pitched whistle' to describe any I've heard. But easy enough to check them. Quote Link to comment Share on other sites More sharing options...
Bob C Posted December 16, 2015 Share Posted December 16, 2015 I would vote for a vacuum leak somewhere. Check all of the vacuum hoses, the intake system, etc. I changed out all of my vacuum lines when I bought the RV 3 years ago because I know that they can create problems that are hard to isolate. Quote Link to comment Share on other sites More sharing options...
linda s Posted December 16, 2015 Share Posted December 16, 2015 Front wheel bearings? My old van the sound would stop when you backed off on the throttle. made very high pitched sound Linda S Quote Link to comment Share on other sites More sharing options...
Derek up North Posted December 16, 2015 Share Posted December 16, 2015 Front wheel bearings? My old van the sound would stop when you backed off on the throttle. made very high pitched sound Linda S With that symptom, I'd guess front wheel drive? Quote Link to comment Share on other sites More sharing options...
cjac Posted December 16, 2015 Author Share Posted December 16, 2015 All the vacuum lines are good. I sprayed carb cleaner around the intake and at the base of the carb. All was good, belts are tight. Might it be my drive shaft center support bearing? How would I check? Quote Link to comment Share on other sites More sharing options...
fred heath Posted December 17, 2015 Share Posted December 17, 2015 Any protrusions from the coach? Could be wind related. Quote Link to comment Share on other sites More sharing options...
Maineah Posted December 17, 2015 Share Posted December 17, 2015 I kind of agree with slipping belts. the alternator belt needs to be pretty close to bow string tight or it will slip at speed. Quote Link to comment Share on other sites More sharing options...
FredNewell Posted December 17, 2015 Share Posted December 17, 2015 Any chance it could be an automatic transmission with a fouled filter? Not my specialty... I had a Chrysler that whistled... badly needed transmission service. Maybe a Toyota automatic won't do this... just a guess. Quote Link to comment Share on other sites More sharing options...
Maineah Posted December 17, 2015 Share Posted December 17, 2015 Another thing you might look at is squashed exhaust pipe. Quote Link to comment Share on other sites More sharing options...
zero Posted December 17, 2015 Share Posted December 17, 2015 I have a high pitched whistle sound when traveling down the road. When I let off the gas it stops, get back on the gas the noise comes back. You need to determine if it is a noise that increases with the truck rolling, or with an increase in engine RPM. What does it do when the truck is not moving and you hit the gas then? If no noise -they you can likely rule out anything that relates to the engine or alternator. That is other then an exhaust leak or restriction that will get worse when you put a load on the engine an get quiet when you let off the gas. If it is a rolling noise - and you've ruled out the wheel bearing and universal joints - what about the driveshaft center support? I has a sealed ball bearing and needs to be replaced now and then. There is no effective way to lube it. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted December 20, 2015 Share Posted December 20, 2015 I am guessing driveshaft or differential. If it was a belt slipping that much it would have burned up by now. The load versus no load is a big hint Quote Link to comment Share on other sites More sharing options...
cjac Posted December 20, 2015 Author Share Posted December 20, 2015 Going down the road and push in on the clutch and the noise stops. Let off the clutch and get back on the gas again the noise comes back. (84 toy mrv 4 speed) Quote Link to comment Share on other sites More sharing options...
PapaFred Posted December 20, 2015 Share Posted December 20, 2015 Mine was doing that when I got to Maineah's house, he tightened belt and it never did it again. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted December 20, 2015 Share Posted December 20, 2015 Belts are easy to check & tighten. Quote Link to comment Share on other sites More sharing options...
zero Posted December 20, 2015 Share Posted December 20, 2015 I can't think of any possible way that a belt noise can be stopped by pushing in the clutch pedal. One has nothing to do with the other. When you push in the clutch - the input shaft of the transmission, output shaft, driveshaft, differential, axles, etc. are all still spinning but with no torque-load on them. I would jack the back wheels off the ground, get under it, and check parts for how smoothly then spin. My first suspect is still the driveshaft support bearing since it gets no outside lube and has to dry out at a certain point. But there are lots of spinning parts to check. Quote Link to comment Share on other sites More sharing options...
cjac Posted December 21, 2015 Author Share Posted December 21, 2015 I will take a close look at the drive line. Might just have to change the u joints and center support bearing since there is no grease fittings. Couldn't hurt with 80,000 miles. I imagine its all factory original. Thanks everyone! Quote Link to comment Share on other sites More sharing options...
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