4L80E build

Status
Not open for further replies.
Nope, twice a year I go out to the twisted sisters for an extended weekend with some friends. Best driving roads in Texas, plus it's out in the hill country (most beautiful part of texas IMO). I don't like driving the vette all the way out and back, so I trailer it instead.
 
Oh sweet. We have the needles hiway and the Irion mountain road here. World class
I know what you mean!
 
Bummer. Looks like the exact same sounds came back. ~3 months later and 5k miles on it... You hear it most in 1st. Much quieter (and lower pitch) in 2nd and gone in 3rd and 4th.

During my disassembly of last transmission, there was visible wear on the rear planetary gears. I bought a used set from WIT because you can't buy new. They appeared to have a little visible wear on them but not like the one I took out.

Am I rebuilding something incorrectly?? I don't understand why this has happened twice unless my first planetary gave up the goose at 250k conveniently after I was in there the first time and if this used set was high mileage too. But both rebuilds I've done have developed this noise about 5k miles after a rebuild and I'm thinking I screwed something up.

I attached a video of me in 1st. It's the metallic whirling noise. It was silent immediately after both rebuilds and developed this.
Also attaching the photos of the planetaries I pulled out 3 months ago.




[Linked Image]

[Linked Image]
 
Last edited:
How's the trans temp?.....You may want to check cooler flow with the rear cooler line disconnected & a hose routed to a bucket before you pull the unit again.

You did replace the rear ring gear....The one splined to the Main Shaft?
 
Trans temp is always 110-130 with current temperatures.

I'm a bit tired and not sure what ring gear you're referring to. I don't remember something splined to the main shaft. I replaced the rear planetaries and and the sun shaft that goes into them. Replaced input shaft with billet and the forward drum with billet. I believe that was all.

I can check flow. Now that you mention it, when I did the first rebuild I installed a new cooler with AN fittings. It's AN6. Wonder if it's just too small... That would be frustrating... The factory lines are pretty small.
 
The factory lines are 3/8"....Same as -6 AN/JIC. I'm feeding my cooler with the factory 5/16" 4L60E cooler hard line on my 4L80E swapped Camaro with no issue.

Red arrow.....Rear/Output Carrier Ring Gear, Also known as Rear Internal Gear in the ATSG manual.

[Linked Image from i.imgur.com]
 
I did not replace that piece. didn't think that moved. I don't remember anything unusual there. Does it develope wear?


Don't see it on my WIT invoice. Dammit. Is this my issue... It would be unfortunate to have gone through 2 planetary sets because of it
[Linked Image]



[Linked Image]
 
Last edited:
It's part of the reduction process in 1st & 2nd gear, Runs on/Meshes with the same Pinion Gears as the Sun Gear.

I like to run the Reaction Carrier, Sun Gear, Output Carrier, & Output Ring Gear as a Matched Set when possible.

Reusing the Output Ring Gear could most certainly cause your issues as it got damaged along with the old Output Carrier & Sun Gear!
 
Well thanks for the insight. How do you request a matched set from WIT? Seems not possible on their website

Looks like I get to see aside a weekend to pull it out and replace the entire set again lol. [censored], I wish I realized that earlier. I'm curious what broke it the first time. Trans was completely silent before it popped the band for reverse. Reused the entire rear set up because it seemed ok but apparently I missed something.

You live and learn I guess lol
 
Also is there a way to ensure I'm getting sufficient lube to the planetaries? Or to improve lube to the planetaries? Because something happened from the first rebuild where they were quiet for >200k miles prior and 5k after the rebuild developed this noise, then I went back and replaced the planetaries and 5k later the sound is back. Could be the ring gear, but what would've caused the problem on the ring gear after the first rebuild when I didn't touch anything on the back half (just replaced clutches and seals and checked end plays. Didn't notice excessive wear)
 
Make sure the Center Support Bushing is oriented/clocked correctly, The Sun Gear Shaft Bushings must be Fluted & not excessively worn.

The seal in the center support that the cooler fitting interfaces must be in good shape.......If you forgot to remove the fitting before trying to remove the center support.....The seal & maybe even the fitting got damaged.

The hole behind that seal must be free of debris/obstructions as it's the main lube feed for the rear carriers. I remove the center support bushing & make d*** sure everything is clean.
 
Last edited:
So I couldn't figure out how to push the bushing out so I sent it as is. Didn't seem bad but perhaps I should revisit that this time. The bushing should've definitely been clocked correctly because I didn't touch it and it didn't make noise before.

The first time I pulled it apart there was 0 debris in my pan. It just popped the band. It's never had debris go through it, so I figured it was clean after I ran brake clean through the hole.


I was paranoid about the center support fitting seal and installed a new one and test fitted it prior to reinstall so I'm confident it shouldn't be that. I am just honestly not sure, because I've done everything suggested but somehow the first gear set got damaged. Makes me concerned and frustrated. But it's part of the learning process.

WIT doesn't have one of my planetaries in stock. Any other suggestions on where you get parts (maybe locally since I live in Bedford and You're in the area too) that are matched?
 
When I was building transmission in high volumes.....I would go around & buy cores from wrecking yards. About the only way to get matched sets.

Give Bishop International a call, They're in Dallas & will have the parts you need. Infact.....Cores are hard to find because of Bishop!
 
They gave me a quote for $95 for used planetaries, ring gear, AND sin gear shaft. That seems dumb cheap! I'll go over and pick it up early next week I think. Anything else you can think I should swap out?
 
Bought the parts. Gears looked ok. Unfortunately they told me they had no way of knowing if it was a matched set, which means it isn't lol.

The bushing in the planetary needs to be replaced.
[Linked Image]
 
Good call. I'll check when I get home. Totally forgot lol.

I'm going to pull the transmission and replace the gear set Saturday morning. At least Bishop is fairly close. Living in Bedford isn't too far away
smile.gif


Going to be rear frustrated this sound comes back in 5k miles.

My plan:
1) check cooler flow, pull rear oil fitting and turn truck on. Will record flow with video. Assuming it's good
2) pull trans and disassemble
3) clean case back out with brake clean.
4) remove bushing from center support and double check to make sure center support oil passage way is free of debris.
5) replace center support bushing (not quite sure how I'll do this)
6) install Output shaft onto planetary.
7) check end plays of stack up to the center support.
8) reinstall and send her home.
 
Status
Not open for further replies.

Similar threads

F
  • Locked
4L80E Rebuild questions (that have not been covered)!
2
Replies
35
Views
17K
F4k
Back
Top Bottom