We have a 99 Savanna 1500 5.7 ltr engine with 138k miles on it. Never had a problem with the transmission, but recently I noticed a whirring/whining sound when putting the van in reverse or drive. It doesn't make the sound when in neutral or park. No leaks and the transmission performs fine. I took it to my mechanic and he couldn't tell where the sound was coming from. He checked the transmission and drove it and said it wasn't the transmission. He thought it might be the belt tensioner or idler pulley, but the noise seems to be coming from under the van and not near the belt tensioner. The noise can only be heard at low speeds with the windows open as normal driving sounds drown it out.
Any help on what this is will be appreciated. Getting ready to take a 2000 k trip this summer and don't want to break down on the road.
First question: Did he put on a hoist and run it in reverse and listen from underneath - or did he just drive it with you?
Second question: Does this noise occur when idling in gear, or only when driving?
Third question: If you shift into neutral while rolling and you hear the noise, does it go away?
I believe your vehicle has a two piece driveline, and if it only occurs when rolling, you could be hearing a carrier bearing starting to fail.
Some slight noise is inherent and can be heard especially in reverse and at low speeds - this is normal. However, if this is a new noise, then I would investigate further. Like you say, last thing you want is to be on a trip and have to get towed in somewhere to have repairs done.
Good luck
fred
05' Layton Lite 170LT Cascade edition
06' Chevy Silverado K1500
We-No-Nah Rendevous, a Ljutic, a Remington, a Hard Rock Pro, a Polaris 450 & Raleigh the Hunter
I have a similar whine/whistle in my truck that I recently noticed. I was setting in a drive-thru with the window down and heard this high pitched sound. When I shifted the transmission into neutral it was gone. I put it in Park and the sound wasn't there either. However, if I was idling in Reverse or any forward gear I could hear it. The transmission seems to shift just fine and I haven't noticed any leaks or strange behavior except for the sound when idling.
However, I think I also have a carrier bearing going out. I get a high pitched whirring sound up to about 35MPH, but it's only when the temps are below freezing. Now go figure that one In warm weather I never hear it, but in the winter it's very easy to hear. I'll get around to that one soon.
Thanks to all for your responses so far. I don't know what diagnostics the mechanic ran but he did tell me he got out his stethoscope and listened to the transmission so I'm assuming he had it up on a rack. He said he also drove it.
The noise occurs when idling in the drive way. If I put it in neutral and coast the noise is not present. The noise does increase a little with speed.
Thanks again. Just trying to get an idea...I'll probably end up taking it to the dealer.
If he did run it on the hoist and listened to the trans, then I suspect you may have another problem.
Since you can reproduce the noise sitting at idle, then set the e-brake, open the hood and get a little water and spritz it on the serpentine belt, see if the noise goes away or changes.
amann_joy wrote: Never had a problem with the transmission, but recently I noticed a whirring/whining sound when putting the van in reverse or drive.
Sounds like the tranny fluid pump to me. You can try changing fluid but doubt it will quiet the noise if that is what it is. Can also get the mechanic to check the pump pressure at the test port to see if it is within spec. A ride down the road is not going to tell you everything.
thanks for all of the suggestions. I took it to the dealer yesterday and "their best transmission guy" checked it out and said there wasn't a problem with the tranny. They acknowledged the sound, but said that with high mileage this sound is not abnormal. Not like a dealer to say nothing is wrong when there is something, I guess. He said he would not have a problem taking the van on a 2000k trip.
We're heading out next Saturday so I'll let you know if they were right. WHS I will try your suggestion, but with my son sitting with his foot on the brake. 6MISFITZ, nice rig. I have the same 4 kids and 2 dogs.
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In warm weather I never hear it, but in the winter it's very easy to hear. I'll get around to that one soon.
