4L60E Information Thread (Includes 4L65E/4L70E)

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).

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.

I have a question @NickTransmissions

If my drum assemblies appear to be installed correctly (1/4 in below the pump resting surface), and the reverse drum is fully interlocked to the sunshell, should the reverse drum rest on the thrust bearing between the drum assemblies?

When I put the reverse drum onto the input drum, it seats onto the thrust bearing. However, when I put the drum assembly into the case, with the reverse drum properly interlocked to the sun shell, it seems to raise the reverse drum off of the thrust bearing by maybe an 1/8th inch. I'm assuming this is normal, but I'm leaving nothing to chance after the last 2 trauma builds I went through.

NOTE: The sun shell does not have the 4 square cut holes for the washer tabs, so I left the washer out.

EDIT: For clarification, it is a 2004 4L65E with all manner of upgrades (Transgo HD2 Kit, reinforced sun shell, 5 pinion planetary gears, corvette servo, sonnax boost valve, Hi-Per Blue Pistons, and some other stuff I can't rightly remember atm.)

Hey @NickTransmissions,
Hope you’re doing well. I really appreciate all your expertise, and sharing your knowledge with the rest of us!
I’m collecting the tools and things I need to swap my transmission, after an apparent forward sprag breakage. (This is what Performabuilt believes is the problem). The Alldatadiy manual suggests I need the tool:
J 21366 Converter Holding Strap
I’ve only found this tool a couple places online and it’s priced between $150-200+, and seems like a pretty basic metal strap. I was hoping you might have a suggestion or, ideally, a cheaper version of this tool you can suggest, which will get the job done. I searched this thread, but didn’t find a tools list. (This would be a great addition imho, but maybe I missed it)
Please let me know your thoughts when you have a moment.

Sam Harris said:

Hey @NickTransmissions,
Hope you’re doing well. I really appreciate all your expertise, and sharing your knowledge with the rest of us!
I’m collecting the tools and things I need to swap my transmission, after an apparent forward sprag breakage. (This is what Performabuilt believes is the problem). The Alldatadiy manual suggests I need the tool:
J 21366 Converter Holding Strap
I’ve only found this tool a couple places online and it’s priced between $150-200+, and seems like a pretty basic metal strap. I was hoping you might have a suggestion or, ideally, a cheaper version of this tool you can suggest, which will get the job done. I searched this thread, but didn’t find a tools list. (This would be a great addition imho, but maybe I missed it)
Please let me know your thoughts when you have a moment.

Click to expand...

Hey Sam, you dont need any converter holding strap for any task, just a tool to align the pump halves when you go to reassemble it, assuming you're going to attempt the repair yourself. I can put a list of special tools into this thread sometime soon...

NickTransmissions said:

Hey Sam, you dont need any converter holding strap for any task, just a tool to align the pump halves when you go to reassemble it, assuming you're going to attempt the repair yourself. I can put a list of special tools into this thread sometime soon...

Click to expand...

Thank you for the advice. I’ll be pulling the trans and shipping from Texas to Pennsylvania.. having the folks who built it fix the problem. Good thing I kept my original.. hoping I don’t blow it up before I get this one back.. and I would like to build the original one of these days. The manual says it’s to avoid any damage to the pump if I recall correctly, but if you say I don’t need it, that’s good enough for me. I’ll be doing this on jackstands, so will be as gentle as possible.