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4L80E - Whining noise in first gear

22K views 6 replies 6 participants last post by  dieselherb 
#1 ·
Ive got a 96 suburban, (labeled 2500, VIN says its a 1500) with a 6.5/4L80E combo. 228,500 on the clock. Trans never been touched. Not sure its even had a transmission fluid and filter change. In first gear when taking off i hear a whirring sound, sounds like an old electric motor spinning up or an old school bus/heavy duty box truck transmission (you know the funny noise they make in first gear). It doesnt slip any, no early or late shifts. All is fine except that noise which is barly noticable over the noise of the diesel, and latly with the heater motor on all the time i dont hear it much at all. The transmission has pulled many miles with a trailer probably never more than 8,000 pounds or so tho. The truck has every fluid cooler known to man, including a big trans oil cooler. The fluid is red but you can tell its a little dirty. I cant tell if it smells burned or not..... it stinks...and all trans fluid stinks...i cant tell the difference. Occasionally when i left off the throttle i feel a thud. The trucks been wrecked before and fixed so i suspect an engine or a transmission mount. (Will a trans mount do that?) Does it sound like i need to be saving for a new transmission? I am only 22 y/o, just bought the truck from my boss for cheap. Love the truck but i am poor. I am trying to start my own business which will involve pulling a 5,000 or 6,000 pound trailer around daily mostly in town. I just need this thing to last until i get to making some decent money and then i can take care of it along with the injectors, exhaust, glow plugs, and ECM upgrade that i want, plus getting the AC fixed. Now, does it sound like i have something to worry about (do i need to start saving my pennies?) Or is the noise i hear normal and a fluid and filter change be all I really need (seeing as its never had one)?? Little bit confused here. I may take the truck on vacation later this year also, 2000 miles round trip. I dont need to get half way there and lose a transmission. Id really be screwed then. What would the expected cost be to have one of these rebuilt??

Thanks ahead of time guys. I need an idea on whats going on and what im in for.
 
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#2 ·
Make sure that all motor mounts are serviceable. Take off the inspection plate to the torque converter and take a close look where the torque converter bolts to the engine flywheel. I am willing to bet the thud you are hearing is stress as the engine is torquing from first gear and causing the whine at the torque converter/pump area. Look for the engine mount on the driver's side to be seperating. from its base. Even the transmission's mount could be doing the same, stranger things have happened. Good luck.
 
#4 ·
the thud you are feeling when you let off the throttle, is that the only time your hear/feel it? does it do it going into gear or when you hit the gas again after coasting? the noise you hear could be caused by a cirty tranny filter. that many miles with no tranny service i would drop the pan and change the filter. good luck, ill check back
 
#6 ·
the thud could be a u joint liek stump jumper said, its also common for a vehicle with that many miles to start to get excessive backlash in the rear end gears which can also cause the thud you describe
 
#7 ·
The whine you hear is the straight cut of the gears(heavy duty) I have two.
 
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