[BubbleHead]

Need some opinions here, and ideas if you have some.

Under VERY LIGHT throttle conditions, and just above 2000 rpm's, I have a loud rumble that I can feel through the pedals, shifter and seat. If I goose the throttle, it goes away until it drops back down to 2000rpms.

The trans was rebuilt last summer buy a local Vette/Chevy mechanic (or someone in his shop) and I also have a Yank 3500 stall converter.

I've noticed it in the past/last year with the A/C on. Within the last 2-3 weeks, it's become common place.

Checked the fluid level, when hot and on a level surf, looks fine and is just above half way in the area marked "hot". Fluid looks clean and doesn't smell burnt.

Any ideas, tips, tricks, things to look for?

 

[-=Jeff=-]

it shifting okay?

you should have had Chuck Johnson at FLP build the trans

 

[Guest]

it shifting okay?

you should have had Chuck Johnson at FLP build the trans

Put in a ZF-6 while he's at it....

 

[Patrick]

Put in a ZF-6 while he's at it....

Funny, I think he mentioned that before.:surprised

 

[grapeknutz]

Check your motor mounts and trans mounts they might be bad.

 

[BubbleHead]

I'll have to check the motor and transmission mounts, thanks for the suggestion.

Jason Smith did the rebuild for me, but I'm not 100% sure if he did it for himself. He also did the 700R4 in my Jeep and that baby is nice and tight still.

I'm worried it maybe the torque converter.

Does anyone know how to tell if a TC is going bad?

The 6 speed swap may become a reality if the tranny shits the bed on me. Time to start saving.

 

[BubbleHead]

Jeff, it shifts fine. I'm starting to think something in my exhaust system has come loose or is loosening up. I'm hearing a metalic jingle from the back.

I'm wondering if the spring/hangers are loose.

 

[-=Jeff=-]

Jeff, it shifts fine. I'm starting to think something in my exhaust system has come loose or is loosening up. I'm hearing a metalic jingle from the back.

I'm wondering if the spring/hangers are loose.

Yeah I probably is something else

 

[BubbleHead]

Update... I have a little more info that I noticed today. If I have the heat on, which I believe activates the a/c compressor, I get the vibration.

If the climate control is turned off, no vibes at all. My a/c works fine as does the heat so, I don't think the compressor is bad but who knows.

So, my question now is why does the load of the a/c compressor (if it's engaged when the heats on) cause a vibration just above 2000 rpms under no or light throttle conditions? I've even experienced it under deceleration.

I'm all ears if anyone has some ideas.

 

[-=Jeff=-]

Update... I have a little more info that I noticed today. If I have the heat on, which I believe activates the a/c compressor, I get the vibration.

If the climate control is turned off, no vibes at all. My a/c works fine as does the heat so, I don't think the compressor is bad but who knows.

So, my question now is why does the load of the a/c compressor (if it's engaged when the heats on) cause a vibration just above 2000 rpms under no or light throttle conditions? I've even experienced it under deceleration.

I'm all ears if anyone has some ideas.

Do you have headers? or stock manifolds?

Are all the factory A/C brackets still there?

 

[BubbleHead]

HMMMMMM... you got me thinking now.

I have headers and all the brackets are still there, except for one. I left off the small support rod that goes behind the alternator.

I'm going to experiment this week and see if I can get the vibration to show up with the Vette in park. I may need the motor under a load for the vibe to show up, but I could get lucky.

Thanks Jeff, you have given me something to look into. I may get lucky and the support rod I left off could be the problem. :excited:

 

[VetteTech81]

HMMMMMM... you got me thinking now.

I have headers and all the brackets are still there, except for one. I left off the small support rod that goes behind the alternator.

I'm going to experiment this week and see if I can get the vibration to show up with the Vette in park. I may need the motor under a load for the vibe to show up, but I could get lucky.

Thanks Jeff, you have given me something to look into. I may get lucky and the support rod I left off could be the problem. :excited:

Man.. this is a hard one to diagnoses from a desk.. LoL.. There are a lot of things that could probably cause this problem... Here is another question when did this vibration start happening.. right after the header install or soon after? otherwise I am thinking the missing brace might not be ther problem..

-Rick

 

[BubbleHead]

Man.. this is a hard one to diagnoses from a desk.. LoL.. There are a lot of things that could probably cause this problem... Here is another question when did this vibration start happening.. right after the header install or soon after? otherwise I am thinking the missing brace might not be ther problem..

-Rick

The headers, trans and torque converter all went in at the same time. After everything was done, I would get the vibration, but only when the A/C was on.

About 2 weeks after I did all that work, the Vette went into the bodyshop for the rest of the summer.

Now, the vibrations became noticeable all the time in the last few months.

I'm going to look into the bracket because it could be a problem along with the only lead I have right now. I'm also going to check all the accesory brackets incase something is coming loose. But, if you have any ideas, I'm listening.

 

[BubbleHead]

P.S. I do appreciate your guys help with this problem!:thumbsup: :thumbsup:

 

[VetteTech81]

P.S. I do appreciate your guys help with this problem!:thumbsup: :thumbsup:

No prob. thats why were here.. Let us know what you find with the bracket and the TV cable..
-Rick

 

[VetteTech81]

Any Update? Did you install the govenor weights yet?

 

[MVR 155]

Tim,
When I put the longtubes on my vette I had to fabricate a spacer to get my AC brackets to work, while I had one of the brackets off I would also get some vibration when the AC was on, without the bracket(s) in place I would be certain this is the culprit to your problem as you described it.

Good Luck

Mike

 

[BubbleHead]

Tim,
When I put the longtubes on my vette I had to fabricate a spacer to get my AC brackets to work, while I had one of the brackets off I would also get some vibration when the AC was on, without the bracket(s) in place I would be certain this is the culprit to your problem as you described it.

Good Luck

Mike

Thanks Mike!:thumbsup:

 

[War Machine]

DAMN!! I left off 2 or 3 of those brackets. :surprised :surprised

I know at least 1 on each side, ALT and A/C. There might have been 2 for the A/C and I might or might not have put it back on, I don't remember. I don't have the A/C charged yet b/c it's been so cool out but now it's starting to warm and the wife will want to use the A/C. I guess I should find a way to put 'em back on, no?

 

[Topman]

similar vibes

My 94 conv has a vibration too, and its weird sometimes the car seems OK, just not like when I bought it, the mufflers sound louder (its got the power effects system on it).
tonight I took a ride and could hear the muffler rattling against the bottom somewhere . I am convinced its the transmission mount, I had downshifted the other day and felt like something broke , thats when the car sounded different , can even hear a whining noise
(probably my driveshaft getting chewed up by the crooked transmission). I'm not sure where the mount is but I'm sure if I jack the car up high enough I'll be able to change it myself.
Just mentioning this for you Bubblehead, someone suggested checking this and you never posted if you checked it yet.