Hi All,
Hoping some transmission Guys will step in . So a long time ago I purchased said 4L60e from what used to be Kiesler transmission . Terrible transaction that got ugly. When I got it in there was immediately a problem. Here’s the problem:
Put it in manual 1st . Floor it and it almost immediately shifts to 2nd or 3rd, it’s hard to tell . If you keep your foot in it and shift to 2nd manually it acts like it’s in neutral. If you don’t shift it manually and lift a bit it goes back into 1st .. Other than that it performs perfectly . Put it in 3rd or 4th floor and it shifts hard and on time . Have probably put 50k or more miles on it .

Have checked all electrical function at the plug on the trans while driving and all is correct .
Have removed the shift linkage and put the trans lever in first and same problem.

Talked to a local trans guy and he said replace the valve body .

What do you guys think ?

If I do go that route can I do it in the car ?
What do I get for a valve body ? I know 0 about transmissions .At the time Kiesler told me the valve body was specifically designed for their trans and they wouldn’t reveal what mods were done . I thought it was crap as they lied about a lot .

This is a mild street car 340

Thoughts?

Which TCM/computer are you using?

I don’t know it’s a standalone. Also early on they sent a replacement . All of the electrical functions tested ok

Does that trans have kick down or TV throttle valve cable linkage?

On an operational note, the 4L60e's are computer controlled and don't use a vacuum module or a throttle valve cable to kick down like the 700R or 2004R's do.

It is either a computer controller issue of a problem inside the transmission itself. If i was facing this, I would change the fluid and filter, and then swap in an aftermarket stand-alone controller in. They are not cheap, but you get what you pay for. Here's one example.

https://www.usshift.com/usq4.shtml

If there are still problems with the shifting, you may want to have your transmission rebuilt by a quality transmission shop who specializes in 4L60's or just buy another transmission outright. Trying to order and swap in a valve body in the car may help, but it may not either. Such is the nature of our hobby.

Correct. It has a tps

Thanks for the reply . The controller was replaced . I was able to test the function while driving the car . Rigged up a couple of volt meters at the transmission harness plug and watched them going down the road .

The problem is in the tranny . Just wasn’t sure if there was something else other than the valve body to consider.

I’ve talked to a couple of shops , they just say replace the valve Body .

You can check out this link to find both upgraded hard parts, shift kits and technical info on setting up and improving the 4L60. With 50k miles on it, it might be prudent to freshen the entire transmission if you are going to be in there.

https://www.sonnax.com/gm_4l60e

Your Mopar is rejecting the GM trans is the issue

Could be a wiring problem from the trans connector to the solenoids or speed sensors.Are you able to rig something up to get codes?

I have wondered that, but wouldn’t it affect it otherwise? Meaning in drive or overdrive it works perfectly.

No I don’t think it’s that smart . It just has a stand alone controller .

I wouldn't trust their computer even though you replaced it once. I get it that changing to a different TCM is an expensive part to throw at the problem. 4L60's have their own inherent weaknesses, but they can be overcome with aftermarket parts including that goofy 3.06 to 1 first gear ratio.

I can't for the life of me understand why on earth someone would choose THAT transmission to retrofit into ANYTHING! They are one of the worst transmissions ever, I run a mopar specialty shop and still end up replacing more 4l60E transmissions than all others COMBINED!

Pretty much what I was thinkin

I'm curious to hear your input regarding a list of the main points of failure in the 4L60's that have met their demise in your shop? Is it generally just burned up clutches and bands or are the failures randomly spread throughout the transmission guts? Thanks in advance.

Solinoids, sensors, the sun shell breaks (we upgrade em all to "the beast"), clutches burn up mostly 4th gear but all of em are suceptible, the valve body spacer plate wears out so the check balls don't completly seal off and sometimes they get stuck in the plate or blow all the way thru.

Thanks for the info.

This is a response I would have expected from the facebook crowd. Responses here are typically intelligent and thoughtful. Yours is neither. Never once in my post did I ask for an opinion on the quality of the transmission. In the future if you don’t have anything constructive, just keep scrolling. Or head over to Facebook. You’ll fit right in .

Pretty informative if you ask me. He explained very well why that is a not a good choice for a trans. He might have taught you something for future use. You did ask what we thought.