Ryan33

okay so I had my 4l60e rebuilt, had it installed on my untuned cammed 6.0 that I recently swapped. I got the trans in and drove it 35 miles home. it did fine shifted good and all. Only problem was the line came off the cooler where the e clip snaps in. fixed it filled with fluid again and drove a good bit more. nothing else happened. I went 4 days later after driving around town to have the truck tuned for the cam and the line blew off in a different place so I just slid it back on and double clamped it. filled with tranny fluid again and made it to the shop. he street tuned it and did fine. drove ten miles on tune and go to stop at a redlight and truck acts like its in neutral and revinng kind of high still. and when I do get stopped it shifts hard back into drive. so I stop check the fluid and it was full. I added a little bit and kept driving. when I got about 30 mmore miles I stopped at another redlight and the same thing happened when I took off in drive it shifted to second and then the engine just revved. so I pulled into gas station to check fluid again it was full. so I filled it 1 1/2 quarts over because I called several people and they said it wont hurt it. so the I put it in drive and it pulls itself about 100 feet when it quit pulling again. stopped and shut it off. made sure all connections were tight under truck and they were. crunk it back up had no forward gears but had reverse. then I manually shifted into first and it went in drove it I shifted to second went smooth, then hit 3rd went smooth again pulled it into drive and it hit 4th and the converter locked like its supposed too. stop at a redlight and I shifted back to 1st and continued again with no issues. then I tried drive again and it shifted into second and it quit pulling again. pulled it into d2 and it shifted into there no issues. made it home just fine. can anyone help me out? is it tune related or what? it was fine before the tune

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mrvedit

First, the "no forward gears" clearly indicates a trans problem, it is not the tune.

You repeatedly had the cooler line come off - how much fluid did you have to add each time? Running a trans a few quarts low will quickly damage it. This sounds like the source of your problems, not the tune.

Ryan33

I have 1,2,3 and in drive 4th goes in and the converter lovka up normally. Sometimes drive will work but over 2k shifting to second it lets go like it just hit neutral. I put 5 quarts back in it the first time and 3 the next time it popped off

mrvedit

There is nothing in the tune to put a 4L60E into "neutral".
I'm confident that driving with 5 quarts down ruined the trans. Sorry.

Ryan33

okay so I got a better insight on it. when it does go into drive if I keep it under 1500 it will shift fine anything over it will jump out of gear. it may be a broken sprag not sure. its just weird it done this after a tune. I heard my tuner get on it a couple times.

mrvedit

Those are the EXACT symptoms of a broken forward sprag.
Sometime the sprag will hold enough to allow very easy acceleration staring in [OD], but often not.
Any heavy acceleration starting in D1 will quickly destroy the overrun clutch.

98CayenneT/A

So if I am doing say a 20 mph roll and am holding D1 then going wot that would be a no no?

Ryan33

Mrvedit. Awesome that's what I thought. And what would cause a broken sprag that fast?

mrvedit

As long as your sprag is OK, that is OK too.
In [D1] (and obviously 1st gear) the load is split between the sprag and the overrun clutch.
In [D3] the overrun clutch is only applied in 3rd gear and not in 1st nor 2nd.
In [OD] the overrun clutch is never applied, but the forward sprag is not used in 4th gear.
This is why you can manually shift from [D1] through [OD] even with a completely broken sprag.

HOWEVER if you install the Sonnax HD 2-3 shift valve, the overrun clutch is applied for all gears in [D1] through [D3]. Because this reduces the load on the sprag, it is highly recommended for high performance builds.

mrvedit

Well, if the original sprag was reused it could have given up the ghost, or a replacement might be defective, but it is likely due to the loss of ATF.

Ryan33

Okay gotcha. Good info from you guys thanks. The trans will be out and the new sprag will be In next week. It had BW sprags in it. But the loss of fluid killed it more than likely

98CayenneT/A

Sounds good, thanks much. I do have the sonnax HD 2-3 shift valve

Now would also be a good time to go to -AN fittings and braided steel lines. Much cleaner setup and you don't have to worry about dealing with lines blowing off again.