727 Shifting Problems

[Harts56]

  Have a 70 Challenger with a 440 cubes 727 trans, 2400 stall, Transgo 2 shift kit and 3:23 gears.  Have had problems with trans not downshifting properly since rebuilt 2 years ago. 
in drive (3rd) to WOT
* 30mph drops to 1st...really well
* 31 mph to 54 drops to 2nd
* 55 mph No downshift at all
When slowing down in drive
* Drops to 2nd at 15-20 mph
* Drops to 1st at 5 mph, hard to tell at that speed.

Brought car to Trans shop that had done great work for my Camaro.  They said it was a kickdown problem, put in Lokar cable no shanges.  Said it was valve body, replaced, no change.  Owner then agreed to do whatever to fix and actually pulled trans out and checked all parts---everything checked out good with high quality parts from prior rebuild.  Reassembled trans, went for test drive, ...BLEW THE MOTOR! 

They did step up and we just installed a new motor but still have the same transmission problems.  I live in a small town, not many choices for transmission shops for a muscle car.  I can't believe this can not be dialed in by the original trans shop or the 2nd shop I went to. 

I had the car for a couple days after the new motor was installed and played with the downshift cable.  Seemed to get better the more slack I took out, however would hold 2nd (2-3 upshift) till 40-45 mph under normal acceleration.  I could "pop" it into 3rd by goosing the gas pedal at 38-40 mph.

Any ideas other than another shop (Don't have any more in town that will work on the car)?

Thanks,

John

[ted]

how does a tranny rebuild result in killing the engine?

[tactransman]

Post some pics of your linkage set up.

[Harts56]

That's what the kid who test drove it at 7,500 RPM in 1st said too!  Thru a rod, cracked the block and piston hit the head. 

Car is in the shop, don't have any pics.  The set up has the Lokar bracket for throttle and downshift at back of carb.  Both trans shop and I adjusted per the instructions, but still had problems described above. 
Only change I really noticed was the more slack I took out of downshift cable (even tightening up .25-.375 inch more than slack really allowed) was downshift from 3rd to 2nd at 55mph instead of 50mph at WOT.  The downshift from 3rd at 30+ only goes to 2nd no matter what adjustment was at.  In 3rd at 30mph or less it does drop into 1st and melts the tires!
Shift point at WOT appears to be at 4800-5000rpm and is no where a crisp as what it should be either.

[Harts56]

OK, got a couple pics now. 
1st pic is with engine off.
2nd pic is with full extension on kickdown cable.  Total pull is 1.375 inches.  If I move accelerator to WOT it also travels 1.375 inches.  So with WOT the downshift cable is 100% taught.  Is this correct?
Ideas?

[tactransman]

Do you have any pics of the lever below? Also,some pics alittle farther away?

[Harts56]

I'll see what I can get in the morning! 

Thanks

[Harts56]

Here are a couple more pics....

[tactransman]

I am not sure,but I think your bottom lever should have the cable hook up shorter on the lever. Drill an extra hole in towards the pinch bolt and try it there. it will make the ratio faster on the transmission.

[Harts56]

Should that help with:
in 3rd at 30 mph WOT it will downshift to 1st, shift into 2nd about 40-45, then third at 65-70
in 3rd at 31 mph to 50-55 will downshift into 2nd and holds till third at 65-70
in 3rd at 50-55 mph no downshift
Shifts from 1-2, 2-3 not very strong (not much more than stock), supposed to have a trans-go 2 shift kit.
Trans shifts at appx 4800 rpm at WOT.

[tactransman]

Yes,it should.

[Harts56]

Taking off for some family time, I'll try that early next week.

Thanks

[Harts56]

Update:  Brought car back to Trans shop.  Stated they would try working with lever as you suggested.  Spoke to them late today and said it now drops 3-2, 2-1 like a champ under WOT, but normal driving 2-3 shift is now at 55 mph!

Owner has been good throughout this whole ordeal.  Patience on both sides is beginning to wear thin and I believe he is at the end of his witts with this car. 

Guess what I don't understand is they have now, removed, torn down (verified parts were good), put together, replace the valve body, installed a shift kit, Lokar Cable, and it still is having problems.  I can't imagine it being something major, but then again I don't do transmissions.....

[tactransman]

Can you post a pic of what they did to the bottom trans kick down lever?

[Harts56]

Car is still at the shop, will pick up tomorrow evening.  I'll try to post a picture in the evening sometime.