NEED HELP Trans torque converter or possibly even rear drive shaft 03 Trailblazer

[mattpaul89]

So the other day I was in the process of performing a crankcase relearn with my scanner tool and right around 2500 RPMs started making a nasty grinding sound i could even feel the vibration under my feet so I thought it might have been the flexplate but after looking at it I didn't see any noticeable damage from what I could see and now when I start it you can hear a winding noise like a power steering pump or something but I know for sure it's not power steering related it's coming from the trans torque converter area and the winding sound does not go away no matter what gear it is in it does get louder in certain gears like reverse or drive as well as with acceleration I'm not sure if this is related or not but I didn't notice a little bit of play in the u-joints as well as a little bit of a clunk when shifting in into or out of park.

 

[mattpaul89]

New item added to shared album

photos.app.goo.gl

 

[mrrsm]

Sounds like an Alternator Bearing is going... and the Noise is more pronounced with the Rise in the RPM. Try isolating the Engine Accessories by removing the Serpentine Belt and after starting the Engine...VERY BRIEFLY Raise the RPM to approximate that in your GIF or Video and listen whether or not the Dreadful, Harsh Sounds repeat. If it does not... Consider having suspicions of these Four Items for Very Close Inspection:

(1) Alternator
(2) Belt Tensioner
(3) Idler Pulley Bearing

As per Jimmy from "1Road":

(4) Water Pump Bearing (Check Wobble at the Outer Fan Cage)

 

[azswiss]

Agree with @mrrsm, sounds like an alternator bearing. Another test would be to listen for any changes in the sound as you load up the alternator. With the engine running and the noise happening turn on the high beams and step on the brake at the same time. If you hear any abrupt changes in the noise as you load and unload the alternator then you know it is in the belt drive area.

 

[TollKeeper]

I will 3rd the course of diagnosis.

 

[mattpaul89]

Agree with @mrrsm, sounds like an alternator bearing. Another test would be to listen for any changes in the sound as you load up the alternator. With the engine running and the noise happening turn on the high beams and step on the brake at the same time. If you hear any abrupt changes in the noise as you load and unload the alternator then you know it is in the belt drive area.

No it's coming from the under the car is definitely transmission related I'm just not sure exactly what when I get home I'll take a better video does anybody have any suggestions on how I can narrow it down and pinpoint the actual issue how would you diagnose a trans related problem and if anyone has any suggestions as far as me making the video and what you would like me to focus on to better help you help me with the diagnostic steps?

 

[TollKeeper]

Finally got a chance to listen to the video... That aint no Alt/Water/Power Steering/etc..

This is just a hunch, as I know very little about the system, but there should be a fuse, or plug, to disable the SAIS pump.

This will generate a CEL light, but its a matter of diagnosis right now.

 

[TollKeeper]

For reference for the pump..

Just for clarification... I know some years had this pump, and other years did not.. Which ones are which.. I dont know!

 

[mrrsm]

Not Likely. The SAIS Pump operates at a FIXED RPM and therefore would not be subject to any changes in Harsh Sound Frequency and Amplitude so evident in the OP's Video with the Rise and Fall of the Engine RPM. The SAIS Pump is Easily eliminated from this Diagnostic calculus ... by removing THIS Fuse:



Even though the VOP mistakenly IDs the SAIS Pump as a "Brake Pump" ...You can get a Better Idea of what the SAIS Pump actually sounds like (...running steady via 12 Volts DC) for comparison at around 1:00 into this Video "In Situ" right under the VOP's Envoy near the Driver's Underside Door Section. This happened because the VOP (Video Original Poster) had a problem with her SAIS Pump NOT turning off due to an Internal Short Circuit:

Since the Flex-Plate connects to the Torque Converter via the Three 120 Degree separated 15MM Bolts... with the engine idling, the TC can thusly operate the Vaned Hydraulic Transmission Fluid Pump when the 4L60E is either in Park, Neutral or of course ...in Gear.

However... if any of the Slotted Aluminum Vanes (TABS) have managed to Shatter or Break free from the Center of the Pump Cavity... then they might rub around inside and create all kinds of "Crunchy Havoc". In some cases those small "Aluminum Dominoes" will wind up dropping down into the Fluid Pan indicating the obvious need to replace the Pump Assembly:

But... If the Trans-Fluid Pump is still providing enough Fluid Pressure to "Hydro-magically" Shift Gears at Speed... there may be something happening with Crankshaft Tail Mount Bolts holding on the Flex-Plate after that area Fractures and Cracks loose...making One Helluva Racket:

https://www.youtube.com/shorts/kPQyBHIkzE4

 

[mrrsm]

THIS Video more closely emulates your "Whining" sound... when viewed from the perspective of the Flex-Plate and Torque Converter in this LS Performance Engine - Transmission:

 

[mattpaul89]

Yes that's it bro right on the money what was the problem in this video?

 

[mattpaul89]

Yes I would have to say that was the initial noise I heard followed by the winding and my first thought was flexplate but when I pulled that Chrome cap and look up at it with the flashlight I didn't see any obvious fractures or anything of that nature but again the angle was not the best either

 

[mrrsm]

The Failure Dynamic has a few vectors:

(1) Failure to Install the Torque Converter with the CORRECT SPACING in between the TC Mount Pads and the Contact (3) pads of the Flex-Plate such that the Outer Orbit of the Flex-Plate is NOT bent or warped out of traveling in a "Perfect Circle" and in a Straight Line. Measure for these proper separations and install Hardened Washers in between that balance the Proper Distances on ALL THREE PADS:

Listen to Nick...

(2) Damaging the Mating Slots of the TC as it slides into the opening of the TC Pump via Clumsy, Careless Installation Technique... requiring that it pass 2 sections to get "Stabbed-In". Internal Stator Vane Bearing Assembly Damage or Friction Plate Internals can also make noise if NOT properly Lubricated by a Working Fluid Pump.

Remember... The 4L60E Torque Converter is NOT a Solid State Mechanism... it HAS Internal Moving Parts that CAN become Damaged:

(3) Excessive Wear of the Crankshaft Thrust Bearings such that the TC "Hunts" longitudinally TOO MUCH and thus, the Flex-Plate-TC will move in and out and can destroy the Inner TC Pump Vanes (TABS) as illustrated in the first Video.This Flexing can also occur around the Center Bolt Matrix at the Crank-Shaft ... work hardening the Plate until it Cracks.

(4) Improper Installation and Torque applied upon the Three TC Flex-Plate Bolts. In some cases...there is an OVAL Hole that needs to be set on one particular TC Boss Pad out of all Three. Also... Having JUST ONE LOOSE BOLT is enough to set the stage for it to self destruct.

(5) Installing the WRONG Torque Converter or one with Internal Damage. Always Pre-Fill the TC prior to Installation. Gradually TOP OFF the Transmission with the Engine Idling in Park. DO NOT OVERFILL THE 4L60E.

(6) BAD MOTOR MOUNTS...can Contribute to TC Failure since the Massive Rotational Parts are always fighting against Torque and Angular Momentum from the Input Power of the Engine... getting "jounced around" and if the Engine moves too much, it can only add to the problem.

 

[mattpaul89]

Here's a video I just took bare with me I'll get a better video any suggestions on where I should focus the camera?

New item by Matthew (Matt)

photos.app.goo.gl

 

[mrrsm]

Well... if the issue has finally been narrowed down to the Stator Support Bearing (inside of the Torque Converter) ...we won't be able to see very much. However, performing a similar Park Neutral Shift Change and throw in a Brake Application while varying the Throttle RPM Up & Down... this might reveal "The Sweet Spot" of this irritating noise.

By the way... Please re-visit the Video I added above to Post #3 coming from Jimmy at "1Road" in which he too had a similar "Whining Sound" that turned out to be caused by a Worn Out Idler Pulley Bearing.

 

[mattpaul89]

So I forgot to mention that my reverse will not ingage I had to push it out of the garage and as I was pushing it backwards i could hear what sounds like gears grinding is that normal when dealing with bad torque converter? or is that a transmission problem? This is a real head ache to pinpoint and I thought the transmission or torque converter would signal the check engine light I don't have one code

 

[mrrsm]

Those SNAFU Sounds = A FUBAR Transmission...

The ATSG Comprehensive OBD2 Diagnostic Guide for The 4L60E,65E,70E & 4l80E,85E Trans

This is a VERY comprehensive 185 Page PDF Service Guide covering the OBD2 Diagnostics for The GM 4L60E, 4L65E, 4L70E, 4L80E and 4L85E Transmissions. It contains a great many contributions from the Members of the GM Automatic Transmission Service Group (ATSG) imparting arcane knowledge, tips and...

gmtnation.com

https://at-manuals.com/wp-content/uploads/2016/manuals/4L60-4L60E%20Catalog.pdf