Clutch & Band clearance can effect shift timing, Your tuner may have been compensating for a late/slow Band Apply. 1/4" of Band Clearance is a HUGE builder oversight!

 

Remember that the PCM/TCM completely controls the shifting. So if the trans is shifting earlier, it is because the PCM/TCM told it to.
If the PCM starts the shift at 5000 RPM and the trans doesn't complete the shift until 6000 RPM, then there is a problem.
As Clinebarger mentioned, the tuner may have bumped the shift pressures more than needed to try to compensate for the excessive band clearance.

In short, this is a tune issue, there is nothing wrong with your trans.

 

Thanks a ton guys.

Just talked to my tuner and he said bring it in Thursday morning and he will have no problem getting it squared away.

 

Figured I would do one more update.
Got my car back from my tuner a while back and it's good to go.
Headed back to the track this past Saturday and mad 8 solid runs with zero issues. The car really has never felt this good and solid. It seems I am officially good to go.
Consistent 12.2x with 1.7x 60's
Car 704

 

Other than a "wait I'm still eating my sandwich" reaction time, it looks very good.
You did a great job rebuilding your trans. I'm sure you are proud of that and no longer fear transmission problems.

 

Lol, ya I don't really know what I was dreaming about there.

Thanks, it really does feel good. It's kind of nice also to know depending on what goes out in the future I can have it out, go threw it and back in and if need be, possibly a 1-2 day turnaround instead of pull it out, bring it somewhere, wait, get it back not knowing exactly what was done and put it back in for a total of 1-2 week turnaround.

I definitely had fun.
I'm thinking of buying a core and doing another one on the side, maybe as a winter project and going a step or two farther than I did with this one with stuff I have learned from you guys threw the many threads

I owe you guys

 

In your guys opinion is there any advantage to running something like amsoil super shift as opposed to like super tech Dex 6 from Walmart which I'm running now.

 

Seeing how many pro builders use the cheaper Dex 3 fluid, any Dex 6 may already be overkill (although I use it). GM determines the specs of anything labeled Dexron 6 (it is their trademark) and I therefore doubt a high priced brand will be any better if even any different.

 

1. Awesome thread and effort!;
2. You should sum up the parts and tolerances used;
3. Tools too; and
4. I put Amsoil ATL in all of our 4Lxx trans.

 

Thanks

Ya, I will do that when I get some time post up parts, tools used and clearances. I have about 4,000 mi. on it and have not had so much as a hitch.

 

First pan drop since rebuild after about 4,500 miles.
I'm happy with what I see. No mucky swamp on the bottom of my pan lol.

Just a thin film of clutch dust on the magnet which I'm assuming is normal wear.....

 

Transmission worked flawless with bolt ons and converter with 1.7x 60's.

Added H/C, more converter and more rpm and away she went on the street yesterday. 1.5x 60's and 7000 rpm shift points.

Think I may have broke the forward sprag in a wot pull on the street.

Manual first holds. In d3 and D.....2nd, 3rd slip and sometimes 1st....... possible pump issue also?

Going to rebuild it one more time before I go to a 4l80e.

Edit: I'm now thinking the forward sprag broke.

 

The forward sprag is the weakest link in the 4L60E.

I got this info from PBA (Dana) at Pro-Built Automatics. Following these instruction helped with my trans.

The later 29 element sprag from Borg Warner has wider elements PN is A74658D (Transtar number). The elements are 12.7% wider than the normal BW sprag. It is a "dual cage" and one of the cages is nylon, and the other has bronze guides instead of the steel ones. It must be used with a 4L60E overrun hub. You should grind in 6 oil slots on the bronze guide that faces the overrun hub for better oiling like the steel guides have. Use the steel guide as a "template" for adding the oil slots. I have used these for when the normal sprag has been problematic.
The inner race must have no wear and must be perfectly flat and have a "mirror" finish. The outer race should be flat and rough. Use 36 grit sand paper and sand it in the direction of rotation by rolling it across a wooden bench and do it about 15 - 20 times. Rinse with solvent and blow it off with high pressure air. The later sprag can be identified by one of the two cages is plastic. I offer these in my Pro Street Elite rebuild kits.

 

That is the sprag I had

 

Did you do the following?

You should grind in 6 oil slots on the bronze guide that faces the overrun hub for better oiling like the steel guides have. Use the steel guide as a "template" for adding the oil slots. I have used these for when the normal sprag has been problematic.
The inner race must have no wear and must be perfectly flat and have a "mirror" finish. The outer race should be flat and rough. Use 36 grit sand paper and sand it in the direction of rotation by rolling it across a wooden bench and do it about 15 - 20 times. Rinse with solvent and blow it off with high pressure air.

 

Yes, I did do that per post 12 in this thread. I do not know for sure if it failed, just a guess as of right now.

 

Is this your dd? If not, and you're in no real hurry to get it back running.... why not just do the 80e? Seems you would be money ahead that way.

 

Enjoyed rebuilding it the first time so want to see what broke and rebuild it one more time. Eventually I'm going to have to do something......

Don't feel like re pinning a new pcm either.

 

Will the Sonnax 2nd gear servo with a wide band and Sonnax input smart drum help support the forward sprag assembly ?

 

Nope, Do you have a HD 2-3 Shift Valve?