Transmission problems..

[cbc_03]

Hi guys, new here but not new to forums in general. I have a 2005 GMC Envoy SLT 4x4 with around 130k miles. Car has no CELs nor has it given any previous indication of impending transmission failure. Last week I took it for a quick drive to a nearby store (maybe 5 miles roundtrip). While I was getting ready to park at home, I heard a small popping noise that came from under the car. After this I lost all gears. The car only accelerates but will not move. I tried in reverse, drive, 1st and 2nd. The car will stay put in Park like normal, but once you shift out of Park, it's like every gear is in neutral. Right after this popping sound, I also noticed that the brake pedal now sinks all the way to the floor (not sure if this is a coincidence as I don't see how brakes and trans are related but thought it'd be good to mention as it happened at the same time).

After doing some research, I checked the shifter linkage as this appears to be a common problem. Linkage is intact and making shifts properly. More research led to me doing a transmission fluid change along with a new trans filter. I drained the fluid and immediately noticed the fluid abnormally thick and almost black along with some very fine metal shavings, nothing big or lumpy. I removed the pan, everything looked normal. Removed the filter. Began fitting new filter when I heard something fall inside the filter neck. I removed the new filter and checked and I found this small metal square. I have no idea where it came from and I cannot find where it belongs. I started to fit the filter back in again when another square dropped down. The second one looks exactly like the first and they appear to be magnetic as they stick to each other. I tried looking these pieces up but I can not find anything regarding these two squares. They 100% fell out from the transmission, that much I am sure. So my question is, can you guys identify these squares? Does this mean my trans is toast? Or could my issue be related to something else? (transfer case, diff, etc) Again, I have not noticed any indication of an oncoming failure nor are there any CELs present. This happened out of the blue. Any insight will be much appreciated! Thanks in advanced

 

[Wooluf1952]

Welcome

In case you haven't heard:
http://gmtnation.com...eres-the-story/

I've never seen those parts. A little more info might help.
Did you buy this truck new?
Is this the first trans fluid & filter change?
Is there a magnet inside the pan on the bottom?

 

[cbc_03]

Just read through that thread. Thanks and sorry if my link to the image violated any rules..

Had this truck since new. Maintenance has always been done at the dealer until the factory warranty/maintenance expired.
This is indeed the first trans fluid & filter change.
Yes, the magnet on the pan itself was covered in fine metal shavings but from what I've been reading, this is normal.(?)

 

[Tiggerr]

Idk what those pieces are... pieces of sunshell maybe? If your fluid was black...no foreward or reverse? ..doesn't sound good...I'm thinking it's time for a rebuild...

 

[Reprise]

I was curious about what those pieces could be - so I found my ATSG manual and took a look.

From the best I can figure (and the fact those pieces couldn't have traveled far from where they broke off), those look like vanes from the pump rotor (inside the pump housing). There are either 10 or 13 of them, and the best way to envision them is like a paddlewheel on its side (those are the 'paddles' that circulate the fluid within the pump.)

You can purchase a whole new pump, or a rebuild kit for the pump. However, many times when those vanes separate from the rotor, they apparently score the inner casing, and then it's new pump time anyway.
Since the trans has to come out of the car to fix it, you might as well consider a full rebuild (or swap another one in, depending on your plans for the truck.
If you rebuild (or swap) - be sure to use a new converter. Not a 'rebuilt' one...not your 'old' one...a brand new one. A good rebuilder (if you use one) will not suggest a reman or used converter - because he doesn't want to have to rebuild it a second time.
If you do swap / rebuild, and take the old one apart, let us know what you find when you open up the case.

 

[Mooseman]

But how would such large pieces move from inside the pump, through passages, and then into the pan.

The sunshell seems to be the most likely source. Are they slightly curved?

 

[Reprise]

But how would such large pieces move from inside the pump, through passages, and then into the pan.

The sunshell seems to be the most likely source. Are they slightly curved?
View attachment 80688

I did consider the sunshell - especially the area you circled - but those 'tabs' are too thick, when you look at what the thickness is of what he's holding in his hand. Just one pic, but they look pretty flat, as well. The one piece looks like it was nesting up against a clutch (?) for some time?

Along with that - if it were the shell - that's even farther back, and if it would be hard for the vanes (?) to get sent through to the intake - I'm thinking it would be harder for a piece that large to get from the shell area to where he found it - ?

At this point, we're all just guessing (I'm not a mech...just a guy who posts to a owner enthusiast site... ) - so hopefully, the OP is curious enough to find out and let us know at some point. I know I've spent enough time trying to guess!

 

[cbc_03]

Sorry for the late reply guys, and thank you for your input on what those pieces might be! I subbed to this thread but never received any updates... Here is where the pieces fell out of exactly:

The pan is still off at this time as I am not sure if I should put it all back together with new fluid as it is or if I should just drop the trans and take it from there. Of course I would like to avoid dropping it but if you guys think it is time for a rebuild I guess I have no choice. I have worked on smaller cars before (Japanese, American, and Euro) but I have not done big jobs on a truck like this one. How difficult is it to drop the trans in these trucks? I am not a mechanic but I am not a novice either, that being said I know there are some jobs that are not recommended to DIY even for experienced backyard mechanics. Is this one of them? Should I tow the truck to a specialist? Also I have read that it may be a better option to source a used low mileage trans as opposed to getting the one I have rebuilt. Is this true?

Thanks again for all your help and I will be sure to check back often for your replies!

 

[Mooseman]

They came out of the filter inlet? Then I would think they came from the pump then and would recommend a rebuild as I would assume it also sent shrapnel throughout the whole tranny. And just seeing the little bit of fluid looks pretty dark to me so I would get it rebuilt.

As far as getting a good used one or getting this one rebuilt, that is entirely your call and depends on your plans for the truck. In either case, I would get it installed by the yard or the tranny shop rebuilding it for warranty purposes, especially on the used one. Doing this on your back on jack stands is not fun unless you can get it really high up. And there's also the transfer case to deal with. You should shop around.

 

[Reprise]

Agree w/ the @Mooseman on this one. It's hard enough doing valve body work on your back. You'll need a transmission jack, and a decent height to raise the truck (prolly 22in or more)in order to get it out from underneath.

If you don't do that, then the truck has to be towed to the mech, as it cant be driven as-is. so there's no point in refilling w/ fluid. Filter, up to you (putting it back in only affects whether more (?) pieces make their way to the pan. No fluid means less mess for the mech, too.

Definitely show those two pieces to whomever you give the job to.

if you wanted to just replace the pump, and see how that goes - i think you still have to remove the trans from the truck, so no help there. Do NOT attempt to remove w/o a trans jack - the thing weighs ~ 250lbs, and will likely flip 180" if not secured properly.

Good luck, whichever way you decide. I took mine to a mech, if that helps you decide. Not enough room in my garage, and i work alone. I didn't enjoy paying the $, but I'd like hurting myself even less (which would be even more $$$$)

 

[mrrsm]

This information is confirmation of @Reprise and @Mooseman 's earliest recognition and mention of the Transmission Fluid Pump as being the Prime Suspect in this disaster. This is because as another possible source of the metal tabs... The 4L60E Transmission Fluid Pump uses a Gerotor Style eccentric inner and outer offset design that achieves fluid pressure by using the two symmetrical Aluminum Rectangles like the ones you held in the palm of your hand, right along with 11 others that are slid into the Slotted Outer Rotor.

They move in and out of those slots as the rotor rotates from the clockwise power coming off of the inner spline and it follows the egg shaped interior of the pump vessel. This makes for a weird path necessary to pick up and pressurize small quantities of the Transmission Fluid per Vane. However... It remains a real mystery as to what caused the destructive problem in the first place... and how the Vanes could possibly wind up dropping down inside the Transmission Fluid Pan. Here is what the Vanes look like and where they are supposed to be inside of the Fluid Pump when things are working properly:



This video is a sub-set from a series covering The Full Rebuild of the 4L60E Transmission... focusing on the re-assembly of just the Transmission Fluid Pump and providing a description of what causes them to fail. The relevant OT viewing begins at around 4:10 into this Video:

 

[Reprise]

That's where I thought his pieces came from, as well, @MRRSM .

What I didn't know was that it was a gerotor-style pump, or that the vanes moved within the rotor - your picture illustrates it perfectly, though. Thanks for finding / posting that.

As for how they 'slipped' out of the assembly - my guess is that whomever takes it apart is going to see some more broken pieces in the pump assembly, perhaps because the rotor seized - ? From what I could find out online, it's not exactly unheard of for this area of the pump to suffer failure - which usually means someone has likely developed a more robust alternative to the OEM part(s).

Wish I'd known that before I had mine rebuilt last fall - I would have spec'd out a HD pump to go along with everything else that got upgraded.

 

[mrrsm]

In the early going... the Slotted Rotor in the 4L60E was fitted for only 9 Rectangular Inserts... but this was "All in Vane" when they were finally upgraded to Thirteen (God how I hate Engineers who insist on using Odd Numbers that bring a Curse right along with them...). You are correct in the idea of updating the Transmission Fluid Pump with a Rotor and Vane Kit that really does bring along some "PIECE" of Mind. I also agree that this particular transmission the OP is thrashing out right now is essentially... a Metal Salad waiting just above the Fluid Plates and Gasket to fall out when exposed. Unfortunately... This Poor 4L60E has Bought the Farm for sure. :>(