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This transmission is from a 2008 chevy truck...Question about the servo pin in a 4l60e. It had a slow leak from a rotted trans cooler line. It didn't get noticed until the transmission started slipping.
The leak was fixed, fluid refilled, and it ran for a little while until 2nd and 3rd gear started slipping. I got it for $25, and trying to learn/figure out what happened....
The 3-4 clutches look dark but not burnt up, and the band looks the same. All other clutches are perfect and look new. The captured steel ball in the servo does not leak.
In removing the input drum the band wouldn't let it go and I had to take the servo cover off..
So I disassembled the servo to test the pin bore, and I discovered that the pin does not go all the way through the bore. It gets stuck at a machined ridge at the end of the bore.
See the pictures. The one with no pin is of the ridge - seen as a straight line reflected by a flashlight. The one with the pin is where the pin gets stuck and as deep as it goes.
Even though the servo retains the pin, should this ridge be there?
This is just for fitting and checking clearances - not actual function.
I have a 700r4 case (older version I know) and the pin bore does not have any ridge machined into it like this one - and he pin slides all the way through without getting hung up on anything.
If I remove the ridge, do you think it would hurt anything?
Interesting.
I am trying to figure out if my trans is a 60e or 70e.
It has the black harness connector and no 4l60e stamped on the case - but it has 4 pinion planets..
Do you know any other indicators of the difference between a 60e and 70e?
I heard the valve body is completely different but they share the same case - can you post a pic a 70e valve body?
I have a 700r4 case and this ridge is not there - yet the servo is the same...
No differences other than a hardened input shaft and 5 pinion planets.
valve body/pump/etc the same
I would take a properly built "60e" to WAY more power than a stock 70
Also didn't the 4l60e have (6) 3-4 frictions and the 4l65e and 4l70e had (7) 3-4 frictions.....
Not debating durability, just referencing that cause he is trying to figure out if it's a 60e or 70e.
I think I saw in his other thread he has a 70e harness but 4 pinion planets so if the transmission has been gone through I guess it's unlikely the 3-4 clutch pack would be the stock one anyways
Yes I am rebuilding it.
Yes that is my other thread with the black plug (supposed 70e) wire harness.
This trans is a stock - never opened up before, and I do not plan on putting it behind anything other than a stock Tahoe or truck etc etc...
The shaft has the ring and the pump has the speed sensor and the harness has the extra wires for it.
Just want to make sure I get the right rebuild kit for this trans - not a trans expert but I am sure there are some here, so I appreciate any info.
Seeing the black wire plug, and the absence of '4l60e' stamped on the case just got me wondering....but being that it has 4 pinion planets I guess it is safe to assume it is a 60e...??
If you're rebuilding it then it doesnt matter if it is a 4l60e, 65, 70...the only real differences will be the servo (if you don't have the corvette ratio...they're $10), the 3/4 clutch stack (which you should upgrade regardless), the planets (seriously...it doesn't matter), and the valve body calibration. Put a transgo "orange box" SK4l60e in it and you vb calibration will be better than any series 4l60.
If you don't have a band worn to hell then you shouldn't be worried about this ridge in the case either. DON'T file it down, or try to drill it, or anything like that. The servo pin bore has to seal 3/4 clutch oil...if you screw up the bore and create a leak you can prettymuch kiss your 3/4 clutch goodbye after rebuild.
01-02-2019, 09:47 AM
4l60e servo pin 
