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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.
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!
Originally Posted by mrvedit
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.
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
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.
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.
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.
05-01-2016, 09:23 PM
