HELP...4L60e not shifting correctly...
 

Alright, I am lost as to what is wrong with my swap. I put a 5.3 LM7 and 4L60e into my son's '82. We got it going in July and have put some miles on it, probably less then 500 miles.

Last week while I was out of town it started not shifting into 3rd gear for him and he limped it home. He checked the fluid and it was low, but no signs of a leak. He topped it off and just let it sit till I got home....

Anyway, I got back yesterday and took it out for a drive while he was at work. I warmed it up first and took an easy drive around the block to warm up the tranny. Checked the fluid level and it was full. The color is a bit dark, but not burnt looking and did not smell burnt. I took it easy and went down the road a ways. Here is what it does...under a moderate acceleration (about 1/2 throttle) is shifts thru the gears fine and even barked the tires going into 2nd. The converter locks up a little soon for me in 4th, but that could be a programming issue...I did a few stops/starts to get the truck into first and then run thru the gears again. Under very light to light throttle (1/4 or less) it goes fine thru 1st, shifts into 2nd and then when it is time to go into 3rd, it just free spins and the motor shoots up in rpm, backing off the throttle does no go to get it to go into any gear...you have to stop or manually put it into 2nd gear to get it to keep going.

What do you guys think it could be? The convertor we are using is a circle d 3200 stall. Like I said, it seems to work good under moderate acceleration, but does not work correctly under light throttle...It is his daily driver and school starts Monday and he needs the transportation...Any ideas??

Re: HELP...4L60e not shifting correctly...
 

Your 3-4 clutches are burnt up.

It's time for an overhaul.

Re: HELP...4L60e not shifting correctly...
 

I don't believe the 3-4 cluthes are burnt at this time. It shifts hard into 3rd and 4th when accelerating at 1/2 or more throttle.

After talking with the guy that did the programming for us, we think that a seal might be messed up when the shift kit was installed or the servo was not put in correctly. This would let fluid by at low throttle and not build enough pressure to complete the 3rd gear shift. But under hard acceleration there is enough pressure to shift into 3rd and 4th. We are taking it to the shop that did the shift kit and servo on Monday to have him look it over. We will see what it looks like....

Re: HELP...4L60e not shifting correctly...
 

Dang speed reading; did it to me again.

Those symptoms are strange.

Re: HELP...4L60e not shifting correctly...
 

If one of the orings on the servo got torn or has a little bad spot it could do what you are experiencing. Almost every time when you remove the servo it will tear the oring too.
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Re: HELP...4L60e not shifting correctly...
 

Any luck or does he still need some time to check it out? I have a similar situation with my trans but it has who knows how many miles on it. It's not a swap but I would like to know what he says so I can check it out on my 3 speed. Especially about the fluilds etc.

Re: HELP...4L60e not shifting correctly...
 

The truck is at the shop that did the trans. He drove it yesterday and wanted to spend more time on it today. Hope to have an answer this afternoon.

Re: HELP...4L60e not shifting correctly...
 

as a past dealer mechanic of 30 years (ase master mechanic) the fact that you all of a sudden lost all trans functions and i assume no trouble codes i believe the neck of the filter isn't sealing to the valve body and is sucking air. If you drop the pan and drag the filter in and out you should feel the seal drag and it must be in good shape with no tears or marks on it at all. If the trans pan has been hit it's highly likely it's damaged. Good luck, Brian F.