4L60E Parts

[Joshuasvt]

Started noticing fuel economy decrease last October - went from 360 miles a tank to 300ish. Shop has checked fuel trims, etc, no issues everything looks normal. Ran seafoam through the engine and gas tank and switched to ethanol free gas (5 tanks now). That made a slight difference (increase) in fuel economy, so I was chalking the decreased mpg to winter blend gas and traffic, but it's declining again.

We made a Costco trip a couple days ago and loaded up the truck with stuff. When we got home I noticed a burning smell. The only other time I've smelled this particular smell is when the clutch burned out on my SVT Focus. I pulled the dipstick and it smells burnt. So I'm wondering if the decrease in fuel economy is somehow related to a possible transmission issue. I haven't noticed any slipping yet. My daily commute is 25 miles each way in stop/go traffic on the highway. I work in Seattle and the commute has gotten worse since last fall. The trans is constantly shifting between 1st 2nd and 3rd - which I know is bad for the 4L60Es.

With all of that said, if I am to rebuild the transmission, what parts should I go with that will keep it running strong as a commuter? Haven't decided if I am going to do it myself or take it to a shop. I know it's best to have a pro do it, but I'm mechanically inclined and very interested in doing the job myself (at least once).

I'll take any advice

 

[Joshuasvt]

175k on factory transmission

 

[OR VietVet]

Reach out to rockola1971 for best trans build info. I personally put a Corvette servo in mine and that woke the trans up. The servo cost shipped to you is almost nothing compared to what it helps the trans with.

https://blog.oregonperformancetransmission.com/

As a side note, I am a former ASE Master Tech and even then I knew that R&R trans was what could do no problem but a build of one was not in my training so I left it to pros. Same with differential builds. Could I learn to do all of it? Sure could but I never did. That may change when a trans or diff problem comes my way though.

 

[rockola1971]

175k on factory transmission

You are putting the cart before the horse. First you need to identify if there is something actually wrong with the transmission. It is indeed not good for the tranny fluid to smell burnt. But what color is it? Its odd that you "noticed a burning smell" and it being the tranny fluid as the culprit putting out that smell. I guess if you had a tranny fluid leak then you would be able to smell it if it were burnt. Speaking of...Whats your fluid level look like in the tranny? I would be more inclined to think that the smell that was similar to a burnt clutch smell is coming from your brake pads because you have a caliper hanging up. Which would cause lower gas mileage.

If your tranny does indeed need a rebuild I dont recommend you learning on your own tranny and I recommend you having someone that is experienced with the 4L60/E models to hold your hand on your first build. You need to know what to inspect and what is or isnt a defect. You dont know what you dont know. There are specialized tools specific to the model that you must have to do a proper rebuild. Reverse clutch removal tool and shaft seal sizers are a few. Most people just dont have these specialized tools. There are steps that must be done during a tranny rebuild to test your build BEFORE it is completely done. You dont want to finish a build, stick in the vehicle, add new fluid to find out that you cut a seal or put a check ball in the wrong place and have to find out the hard way right after your tranny smokes the clutches that you just installed new. By all means save yourself some money and pull yours and take to tranny shop and then bring back and install yourself. They are interesting to look inside and see how it works but definitely not near as easy as taking apart a starter and replacing brushes or rebuilding a brake caliper. I encourage you to watch a youtube video of a start to finish rebuild of a 4L60E to see what all has to be done. Have a transmission case washer at home? Most dont. Cleaniless is king for a tranny rebuild.

 

[Joshuasvt]

I personally put a Corvette servo in mine and that woke the trans up.

Interesting. What does the corvette servo in our transmission exactly. How does it change it? I’ve read (here) about people using them, but never learned how they change the trans.

 

[Joshuasvt]

But what color is it?
Normal red trans fluid color. No discoloration.

Whats your fluid level look like in the tranny?
Fluid level is normal.

I would be more inclined to think that the smell that was similar to a burnt clutch smell is coming from your brake pads because you have a caliper hanging up. Which would cause lower gas mileage.

Just had the brakes serviced by my mechanic. They’re good to go. MPG loss started prior to brake service.

If your tranny does indeed need a rebuild I dont recommend you learning on your own tranny and I recommend you having someone that is experienced with the 4L60/E models to hold your hand on your first build.
Understood Was just a thought I was toying with.

You dont know what you dont know. YES!

I encourage you to watch a youtube video of a start to finish rebuild of a 4L60E to see what all has to be done. I’ve been researching this for a while now. It’s something that is always peaked my interest.

With all that said, I was curious about what parts I should look for. Thanks for the advice.

 

[OR VietVet]

Interesting. What does the corvette servo in our transmission exactly. How does it change it? I’ve read (here) about people using them, but never learned how they change the trans.

Click on the link I supplied and they will explain better than I can. Plus, plenty of you tube videos showing install and what happens. Firmer shift.

 

[rockola1971]

Interesting. What does the corvette servo in our transmission exactly. How does it change it? I’ve read (here) about people using them, but never learned how they change the trans.

The corvette servo applies about 50% more holding power to the 2-4 band. This only affects 2nd and 4th(OD) gears. If you are getting on it hard like a launch from a dead stop then shifting from 1st to 2nd can result in a 2nd gear slip and will prematurely wear down the 2-4 band to the point eventually you will have no 2nd and 4th. It also helps tremendously with the boneheads that insist on towing in 4th.

 

[OR VietVet]

The corvette servo applies about 50% more holding power to the 2-4 band. This only affects 2nd and 4th(OD) gears. If you are getting on it hard like a launch from a dead stop then shifting from 1st to 2nd can result in a 2nd gear slip and will prematurely wear down the 2-4 band to the point eventually you will have no 2nd and 4th. It also helps tremendously with the boneheads that insist on towing in 4th.

I knew I should have just said wait for Mike to explain.

 

[rockola1971]

With all that said, I was curious about what parts I should look for. Thanks for the advice.

Ok....you asked for it.

Clutch, steels, seals kit (High energy alto)
Bushing kit
Corvette servo
Beast sunshell
Kevlar 2-4 band
valve body update kit
filter and pan gasket
new fluid
torque converter
Most likely a valve body separator plate
Pump rebuild kit
planetary gear set
And any other hard parts that fail inspection