Unusual noise when shifting out of 1st gear.

[Marty395]

I have been hearing what sounds like a bottle of rocks being shaken when shifting out of 1st gear from a standstill. I can only reproduce the noise when accelerating above 2000rpm. I've had the transmission, transfer case & both diffs serviced about 50k ago. I also just replaced the plugs, t-stat and the TB was cleaned. Is it time for another transmission flush? What are the recommended service intervals for drive train fluids? Any help is appreciated.

Thanks,

Marty

 

[jrSS]

Diffs ans transfer case 50k....tranny 100k. What fluid was used in the tranny?

 

[Old Coot]

Is it gearbox noise? or detonation of fuel in the engine? Engine knock can sound like that under acceleration, especially so when the ignition timing is advancing. I switched to 89 octane in my Caravan when we started getting the winter blend fuels and it went away. It may be worth a tank full of higher octane fuel and see what happens.

 

[Marty395]

Diffs ans transfer case 50k....tranny 100k. What fluid was used in the tranny?

I'm not sure, the service was done at a GMC dealership (don't judge me). I would assume they knew what they were doing. I would have liked to go with royal purple but was told they could not...

 

[Marty395]

Is it gearbox noise? or detonation of fuel in the engine? Engine knock can sound like that under acceleration, especially so when the ignition timing is advancing. I switched to 89 octane in my Caravan when we started getting the winter blend fuels and it went away. It may be worth a tank full of higher octane fuel and see what happens.

I'm not positive if its gearbox noise or engine knock. I guess by process of elimination I'll find out. I'll try higher octane fuel ( maybe a little octane boost as well), check timing and flush trans. I've got 117k on the dash so I'm sure a little preventive maintenance wont hurt any.


Any other suggestions?

 

[Sparky]

I know this sounds funny but seriously, check your hood prop rod. Wrap a rag around it or something right where it sits next to the fan shroud and take it for a test drive.

Mine was doing the exact same thing and it bugged me that I couldn't figure it out. Then I read something either here or on the old site about the prop rod and it got me thinking. I now have a piece of foam wrapped around mine and no more rattle at 2000-2500 RPM

 

[Marty395]

I know this sounds funny but seriously, check your hood prop rod. Wrap a rag around it or something right where it sits next to the fan shroud and take it for a test drive.

Mine was doing the exact same thing and it bugged me that I couldn't figure it out. Then I read something either here or on the old site about the prop rod and it got me thinking. I now have a piece of foam wrapped around mine and no more rattle at 2000-2500 RPM

Thanks. I will try that asap. Sounds like an easy fix, cheap too.

 

[Old Coot]

I know this sounds funny but seriously, check your hood prop rod. Wrap a rag around it or something right where it sits next to the fan shroud and take it for a test drive.

Mine was doing the exact same thing and it bugged me that I couldn't figure it out. Then I read something either here or on the old site about the prop rod and it got me thinking. I now have a piece of foam wrapped around mine and no more rattle at 2000-2500 RPM

Until one isolates the problem, it can be difficult to determine the root cause of it. This might sound funny to some ... but, I like it. Great idea!

 

[Sparky]

Thanks. I will try that asap. Sounds like an easy fix, cheap too.

If that does prove to be it make it a little more permanent than just something wrapped around it. I used some duct tape to hold the foam on the rod on mine. Don't want to have it come off the rod and somehow get sucked into the fan or wrapped around the pulleys or belt!

 

[jeffro312]

This is probably a long shot... but just the sound u describe reminds me of when...

i test drove my rainier before i purchased this and heard a simular noise passenger side mostly it seemed. higher rpms and shifting. ended up being a exhaust manifold... you sheild could be rattling also... just another thing you can check...

not sure of your exact noise but i got a fast ticking noise kinda sounded like a harly just no where near as loud. best way i can describe it

 

[Mommymobile8]

I'm not sure if this is related to the problem your having but a while back my voy was making that noise like rocks inside the tranny from take off and usually when it was shifting into other gears, but I replaced the torque converter fluid and filter and it solved the problem, no more noises..I'm not sure but if there is something wrong w the torque converter it might show a CEL, as mine did..

 

[Marty395]

This is probably a long shot... but just the sound u describe reminds me of when...

i test drove my rainier before i purchased this and heard a simular noise passenger side mostly it seemed. higher rpms and shifting. ended up being a exhaust manifold... you sheild could be rattling also... just another thing you can check...

not sure of your exact noise but i got a fast ticking noise kinda sounded like a harly just no where near as loud. best way i can describe it

Now that you mention it, my exhaust does rattle when parked and running...

 

[Marty395]

I'm not sure if this is related to the problem your having but a while back my voy was making that noise like rocks inside the tranny from take off and usually when it was shifting into other gears, but I replaced the torque converter fluid and filter and it solved the problem, no more noises..I'm not sure but if there is something wrong w the torque converter it might show a CEL, as mine did..

I do not have a CEL, but Ill look into it. Thanks.

 

[AbsoluteZero]

My S10's catalytic converter would make a "rocks in a can" sound at low rpm. The guts were loose.