DenaliXL
Contributor
Posts: 122
Reg: 02-25-07
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04-18-12 12:42 PM - Post#2216551
Almost sounds like a belt noise but it doesn't do it if I'm at the same rpm's when not towing a heavy load. I wouldn't think the belt or accessories know what the load is.
Its been happening for years (at least since I got my big trailer) and I've always been curious. Drives fine. Trans and convertor have been changed during these years (at 117K) to an aftermarket so its not that unless its in the design. Its at high rpm like when the peddle is on the floor going up hill in tow mode with approx. 8000lbs on back. If I feather the throttle to make it upshift and lower the rpm's, it's gone the second it shifts.
Any thoughts?
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JaVeRo
Member
Posts: 280
Loc: East Texas
Reg: 02-02-06
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04-18-12 01:10 PM - Post#2216556
In response to DenaliXL
Would you describe the sound as maybe a whistling noise? Maybe sucking air somewhere that only happens when the vacuum is high like pulling a load?
It's just a wild guess.
I have no idea how you would find it.
James
2003 S10 Blazer 4wd (wife's)
2001 S10 Crew Cab (wife's mail truck)
1996 K1500 (mine)
1979 GMC 3/4 ton 2wd 4spd with a "Gilley's" bumper sticker, my first brand new truck.
2006 K1500 Company Truck
2006 K2500 NV4500 4.10's |
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DenaliXL
Contributor
Posts: 122
Reg: 02-25-07
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04-18-12 01:12 PM - Post#2216558
In response to JaVeRo
Interesting thought but not like air being sucked.
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DEI8FAN
Member
Posts: 670
Age: 54
Loc: Western, N. Carolina
Reg: 02-01-05
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04-22-12 04:24 AM - Post#2217781
In response to DenaliXL
My Z71 does it, I haven't found the source either.
1959 El Camino
1970 El Camino
1981 Corvette
2004 Z71
2005 Monte Carlo
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fbi9c1
Frequent Contributor
Posts: 1692
Loc: Los Angeles
Reg: 08-07-07
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04-22-12 12:20 PM - Post#2217908
In response to DEI8FAN
How about coolant is blowing out the overflow and onto the belt(s)?
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DEI8FAN
Member
Posts: 670
Age: 54
Loc: Western, N. Carolina
Reg: 02-01-05
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04-23-12 04:19 AM - Post#2218137
In response to fbi9c1
No not at all. It sounds like it could be a leak on the breather assy. But it haven't found one. It only does it pulling a load in 2nd on a grade at 3500 rpm or better. (We have some pretty good grades around here)
Only thing I come up, It must be the design of the filter-intake setup.
1959 El Camino
1970 El Camino
1981 Corvette
2004 Z71
2005 Monte Carlo
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DenaliXL
Contributor
Posts: 122
Reg: 02-25-07
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04-26-12 06:33 PM - Post#2219500
In response to DEI8FAN
Definately not coolant but appreciate the suggestion.
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DEI8FAN
Member
Posts: 670
Age: 54
Loc: Western, N. Carolina
Reg: 02-01-05
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04-27-12 03:57 AM - Post#2219595
In response to DenaliXL
I am going to pull my camper through the Smokey Mountains this morning. I'll give it another listen.
1959 El Camino
1970 El Camino
1981 Corvette
2004 Z71
2005 Monte Carlo
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lady3bglover
Forum Newbie
Posts: 24
Age: 47
Loc: Alvin, Texas
Reg: 05-01-12
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05-03-12 01:49 AM - Post#2221834
In response to DEI8FAN
And you're on your stock 3.73's?
02 Silverado
Ls6/Ls2, Flaco Perf & Tuning
FLT Lvl 5, CDS 3400
Posi and 4.10
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DEI8FAN
Member
Posts: 670
Age: 54
Loc: Western, N. Carolina
Reg: 02-01-05
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05-03-12 03:53 AM - Post#2221846
In response to lady3bglover
Yep, its a 2500lb pop up, and I still cant tell where its coming from.
1959 El Camino
1970 El Camino
1981 Corvette
2004 Z71
2005 Monte Carlo
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lady3bglover
Forum Newbie
Posts: 24
Age: 47
Loc: Alvin, Texas
Reg: 05-01-12
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05-03-12 05:36 AM - Post#2221872
In response to DEI8FAN
You didn't mention what trans and stall did you swap to, and what color is your trans fluid?
Are you able to read trans temp?
Just asking so we can weed through.
02 Silverado
Ls6/Ls2, Flaco Perf & Tuning
FLT Lvl 5, CDS 3400
Posi and 4.10
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DenaliXL
Contributor
Posts: 122
Reg: 02-25-07
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05-03-12 09:30 AM - Post#2221960
In response to lady3bglover
The 4L65E was rebuild with heavy duty internals and I believe the new convertor to be stock stall. Fluid is pink and trans temp guage reads same as before rebuild (gets to ~ 212 degrees on a long summer drive approx. matching engine temp.).
The reason that I did not include these details is because the sound did not change before or after the rebuild so I'm assuming it's not trans related.
Edited by DenaliXL on 05-03-12 09:31 AM. Reason for edit: No reason given.
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lady3bglover
Forum Newbie
Posts: 24
Age: 47
Loc: Alvin, Texas
Reg: 05-01-12
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05-03-12 10:26 AM - Post#2221972
In response to DenaliXL
I have an FLT Lvl 5 (65e) w/70e output shaft and a Circle D 3400 Converter.
You on the other hand have a rebuilt 65e and the stock converter, or was the converter worked on as well?
If my trans temp hit 212* I'd have a cow. And I'm not even towing staying well under 200* even when I'm fast lapping the daily driver. (Ok 427rwhp I think I'm entitled to have a little fun.)
When your not towing, and crusing at 70+ Mph, do you ever see your Rpms jump a litle, even if you're speed is steady?
This is where I'm going an I think it's a good shot in the dark. I think you can't figure out where the squealing is coming from b/c it's in the coverter, and it's coming from the clutch not being fully engaged, causing friction, and there's your high temp.
If I'm wrong, I tried. If not, don't waste your time with a rebuilt stall. I learned my lesson.
02 Silverado
Ls6/Ls2, Flaco Perf & Tuning
FLT Lvl 5, CDS 3400
Posi and 4.10
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DenaliXL
Contributor
Posts: 122
Reg: 02-25-07
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05-03-12 11:48 AM - Post#2221998
In response to lady3bglover
The convertor was replaced with new aftermarket. Same noise with the old and new.
I've often found that after a long drive in hot weather, engine and trans temperatures become the same. I am assuming the engine has 212F stat.
So you are thinking the convertor is slipping? Interesting thought for sure. I'm no expert on the electronic tranmissions but two thoughts come to mind:
- wouldn't a modern convertor have some sort of electronic lock up?
- wouldn't the computer throw a code pointing to the trans if the engine rpm where that radically different from the vehicle speed?
Now that you mention it, I have when towing, and not everytime that I tow, gotten a code that equated to rpm not within expected range. Forget the code number but it didn't mention trans/convertor slip as a possible cause.
Scary thought for sure.... trans was built by a well known expert that claimed it could now easily handle towing 12,000+ lbs while I'm towing around 8,500lbs.
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lady3bglover
Forum Newbie
Posts: 24
Age: 47
Loc: Alvin, Texas
Reg: 05-01-12
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05-03-12 12:03 PM - Post#2222004
In response to DenaliXL
Right now I think your clutches are glazing, so the bad stuff still really hasn't come yet.
Get the code, it's easy to Google. 
02 Silverado
Ls6/Ls2, Flaco Perf & Tuning
FLT Lvl 5, CDS 3400
Posi and 4.10
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