4L60E Information Thread (Includes 4L65/70/75)

NickTransmissions · Aug 16, 2024

Bumping this thread up with a new video on measuring servo travel/adjusting band clearance in 700R4s and 4L60Es....This vid is one of a two-part series and focuses on GM factory servo and hardware. PT2 will focus on aftermarket servo set ups (Coming soon).

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NickTransmissions · Sep 21, 2024

Bumping this thread with a new video on 700R4 and 4L60E Forward Drum Repair...The most common pattern failure, by far, is the 3-4 clutch pack burning up...The primary reason for this in my view, is leaks developing at the base of the input shaft where it's pressed into the drum...Over time, milage, stresses and other factors combine to weaken the drum to the point it's no longer making a perfect seal at the 2-3 feed circuit and fluid begins to leak into the case under high pressures when it should be going directly to the 3rd clutch piston to apply and hold the 3-4 clutch pack...When this starts happening, 3-4 clutch failure isn't far behind.

I show a potential repair procedure using Loctite retaining compound, that if ultimately proves itself to work under operating temperatures, will be a viable option for those looking to repair drum assemblies with mild to moderate leaking in lieu of replacing the drum.

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Vbb199 · Nov 6, 2024

Nick i have a question for you, relative to 4L60e stuff for anyone here. I build automatics myself, mostly 3 sp and 4 sp. not for a living but for myself and friends, from stock to higher hp.

Whats your goto method for deleting the PWM function of the tcc solenoid?

Some install the transgo SK-4L60E with the bigger valve
Some pin the valve with 700r4 spring or two check balls
Some remove the outer O ring and file/grind a notch straight to the filter.

What do you do? And whats the consequences of one vs the other?

NickTransmissions · Nov 6, 2024

Vbb199 said:
Nick i have a question for you, relative to 4L60e stuff for anyone here. I build automatics myself, mostly 3 sp and 4 sp. not for a living but for myself and friends, from stock to higher hp.

Whats your goto method for deleting the PWM function of the tcc solenoid?

Some install the transgo SK-4L60E with the bigger valve
Some pin the valve with 700r4 spring or two check balls
Some remove the outer O ring and file/grind a notch straight to the filter.

What do you do? And whats the consequences of one vs the other?

Those will all work but I like the Fitzall valve as it completely seals the bore and is appx $25.00. The others convert the PWM to On-off as well and ill use those methods if the bore is otherwise fine when vac tested.

Vbb199 · Nov 6, 2024

NickTransmissions said:
Those will all work but I like the Fitzall valve as it completely seals the bore and is appx $25.00. The others convert the PWM to On-off as well and ill use those methods if the bore is otherwise fine when vac tested.

How do you feel about the big pressure spike? Ive heard things about it allegedly tearing up converter bushings and this and that but i havent seen any evidence of it myself. Im speaking more so when the PCM/TCM on/off pressure tables have been modified to match what you physically want the converter to do if that makes sense.
Most stock management has the converter slipping in and out, and it can be changed for full lock/unlock with no slip, but you can still see some slip on a monitor/laptop until you fully lock the valve out.

Does the pressure become dangerous to anything with a blockoff/pin + PCM modification

NickTransmissions · Nov 6, 2024

Vbb199 said:
How do you feel about the big pressure spike? Ive heard things about it allegedly tearing up converter bushings and this and that but i havent seen any evidence of it myself. Im speaking more so when the PCM/TCM on/off pressure tables have been modified to match what you physically want the converter to do if that makes sense.
Most stock management has the converter slipping in and out, and it can be changed for full lock/unlock with no slip, but you can still see some slip on a monitor/laptop until you fully lock the valve out.

Does the pressure become dangerous to anything with a blockoff/pin + PCM modification

Ive been using those and similar valves for close to 15 years and so far, no issues but have heard/read other builders report those concerne. Use Transgo's TCC reg valve from their SK4L60E shift kit if you have reservations about the Fitzall valve - Ive never had any issues with them either.

Vbb199 · Friday at 6:25 PM

Hey nick i have a question... ive googled around and i cant seem to find clear answers. Maybe you might know.

I have a 4L60e in a 2003 trailblazer. I dont think its the original, so i dont really know if its an actual 03 or not, but its working and functioning now, except the tab that holds the servo side cover in place broke off, so now i gotta swap cases. The only numbers i can see on it until i get it out is the casting number(24207965), and some sticker from the reman place thats got 03tdd712076113 on it. I'll have it out shortly and can get the GM sticker off of the top , if its still there. Its a 2pc case.

The prospective case im eyeing however is identified as a 4L65e case. 5KCD on the gm sticker, 24220974 cast into the side of it.

Can i simply swap my internals and valve body and all over to the 65e case? Or is there differences in the valve bodys and the casing?

If ive got to freshen up the 65e valve body thats ok, but if i didnt have to, that'd be great.....

If you have the time, or care to, perhaps you can enlighten me...

I appreciate it either way....
Thanks

NickTransmissions · Friday at 9:07 PM

Vbb199 said:
Hey nick i have a question... ive googled around and i cant seem to find clear answers. Maybe you might know.

I have a 4L60e in a 2003 trailblazer. I dont think its the original, so i dont really know if its an actual 03 or not, but its working and functioning now, except the tab that holds the servo side cover in place broke off, so now i gotta swap cases. The only numbers i can see on it until i get it out is the casting number(24207965), and some sticker from the reman place thats got 03tdd712076113 on it. I'll have it out shortly and can get the GM sticker off of the top , if its still there. Its a 2pc case.

The prospective case im eyeing however is identified as a 4L65e case. 5KCD on the gm sticker, 24220974 cast into the side of it.

Can i simply swap my internals and valve body and all over to the 65e case? Or is there differences in the valve bodys and the casing?

If ive got to freshen up the 65e valve body thats ok, but if i didnt have to, that'd be great.....

If you have the time, or care to, perhaps you can enlighten me...

I appreciate it either way....
Thanks

5KCD indicates a 2005 unit/case so you'll need to grab a 2004+ pump body that does not have an O-ring groove on the outer diameter if your existing transmission's pump body has an O-ring. The pump body and case were changed starting in 2004 - the change allowed the use of a perimeter wedge seal that sits between the pump and case and seals that area off.

Beyond that, you can swap everything over as-is.

Vbb199 · Saturday at 8:57 AM

NickTransmissions said:
5KCD indicates a 2005 unit/case so you'll need to grab a 2004+ pump body that does not have an O-ring groove on the outer diameter if your existing transmission's pump body has an O-ring. The pump body and case were changed starting in 2004 - the change allowed the use of a perimeter wedge seal that sits between the pump and case and seals that area off.

Beyond that, you can swap everything over as-is.

I've heard you can remove the o ring on the earlier pumps and use the wedge seal with them, is there any truth to that? Thanks for you time nick.

NickTransmissions · Saturday at 9:14 PM

Vbb199 said:
I've heard you can remove the o ring on the earlier pumps and use the wedge seal with them, is there any truth to that? Thanks for you time nick.

Try it if you want but be prepared to do the job twice if it doesnt work out.

Or simply get the correct pump body for that 05 case - not sure why that would be difficult as they're everywhere.

Vbb199 · 2024-11-21T05:38:12-0500

NickTransmissions said:
Try it if you want but be prepared to do the job twice if it doesnt work out.

Or simply get the correct pump body for that 05 case - not sure why that would be difficult as they're everywhere.

If im not mistaken, 2003 or 2004 is the year the O ring pump seal got replaced with the Wedge seal style; im sure you know exactly when.

Either way... "for the books" - i removed the O ring of my presumed 03 pump installed it and it works in the 05 transmission without leaking or issues.

NickTransmissions · 2024-11-21T06:51:02-0500

Vbb199 said:
If im not mistaken, 2003 or 2004 is the year the O ring pump seal got replaced with the Wedge seal style; im sure you know exactly when.

Either way... "for the books" - i removed the O ring of my presumed 03 pump installed it and it works in the 05 transmission without leaking or issues.

Glad it's working (i.e. not leaking) but keep an eye on it...I've been told by folks who tried it said it started to leak after a while...DYIers have a bit more flexibility when it comes to risk and your appetite for it will always be greater than a transmission builder's given we do this for a living and can't afford comebacks due to knowingly mixing incompatible parts together to save a few dollars...

Vbb199 · 2024-11-21T07:33:57-0500

Honestly im just experimenting around , i have the 05 pump, but the rotor exploded and i'd have to remachine the pump at my shop, where as the 03 pump ive already machined, put new rotor/vanes in and upgraded....

Guess we'll see what happens.
Thanks for your help again Nick

4L60E Information Thread (Includes 4L65/70/75)

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