Shift Sequence

[crouse]

High speed WOT run. 1st gear then 2nd gear then 3rd gear then what?

Converter Lock then OD or OD then converter lock.

What's best? Can our transmissions handle a WOT shift into OD? I know some transmissions retard the timing before the shift into OD.

[ckadiddle]

If I ever get enough open Private Track, I will let ya know. I can tell ya that WOT from dead stop mine hits the 2-3 shift just before I cross the quarter mile mark. Thats about 94-95 mph at that point. That's with a tune from DR. I have always wanted to wind it out in third then wind out overdrive. Most likely will be going so fast the paint will melt off from air friction.

[Drock96Marquis]

DON'T WOT into o/d!


There is also 2nd and 3rd gear convertor lock.

[crouse]

Dennis Reinhart helped me with my tune so that the TC will not lock in 2nd gear.

So 1st, 2nd, 3rd then TC lock under WOT.

[Architect]

DON'T WOT into o/d!
There is also 2nd and 3rd gear convertor lock.

Now y'all have got me confused...
Before I had my 4:10 installed...
I had the Xcalibrator tune installed...
The Marauder would shift into 4th (OD) at 120 +- WOT...
I only did it once...
So I should not do this?
Explain converter lock also...
Man y'all are a wealth of information...
Architect

[JMan]

Here I go again talkin' trannies! I should never do this!!!
The convertor locks or tries to lock in first gear in the factory tuning even at wide open throttle at some RPM and speed level (which I do not know). Right at the second gear shift point it unlocks and after complete, reapplies. That's that famous 1-2 bog in the 4R70W, where the "W" stands for wide range as in gear ratios. It goes - unlock, shift, reapply, bog, in that order. That is my biggest beef with the factory tune. There's 3 tenths left on the table right there just waiting to be tuned in! The same happens in the subsequent gear changes as well, but the "W" isn't quite as drastic from 2 to 3 and even less from 3 to 4. I'm sure someone with a clue will pipe in with the exact numbers for study.

If the RPM after the 1-2 shift only dropped to the peak torque "sweet spot", you'd drop a bunch of time in the 1320. Of course, if you have a respectable tune from one of our vendors, this is not a problem any longer!

[metroplex]

There's a TC lock/unlock schedule for 2nd, 3rd, and 4th gears.

My SCT standard tune:
WOT, 1st, 2nd, 2nd gear TC lock, TC unlock, 3rd, 3rd gear TC lock... finish line (straight line racing).

[Zack]

If you have a tune from anyone, the converter is always locked at WOT, period.

[JMan]

If you have a tune from anyone, the converter is always locked at WOT, period.

Wow! If that's the thinking out there, I don't want someone else's tune. That makes no sense to me whatsoever. What is the train of thought there? Fill my little brain in on the details, please. My thinking, however wrong it may ignorantly be, is that slippage in the convertor would allow the engine to rap up more quickly into the power band in each gear thereby defeating the load more rapidly. Please, explain my misgivings so I understand. Once again, I'm not a tranny-smart fella!

Thanks,

J

[metroplex]

If you have a tune from anyone, the converter is always locked at WOT, period.

It's not physically possible for 1st gear on a standard 4R70W.

[Zack]

It's not physically possible for 1st gear on a standard 4R70W.

I know that.

[Zack]

Wow! If that's the thinking out there, I don't want someone else's tune. That makes no sense to me whatsoever. What is the train of thought there? Fill my little brain in on the details, please. My thinking, however wrong it may ignorantly be, is that slippage in the convertor would allow the engine to rap up more quickly into the power band in each gear thereby defeating the load more rapidly. Please, explain my misgivings so I understand. Once again, I'm not a tranny-smart fella!

Thanks,

J

A locked converter makes more power to the wheels.
That is the only explanation I have to give.

[metroplex]

There's also the argument that a locked converter isn't necessarily the best for getting the fastest ETs for a mildly modified N/A engine.

[Meteorite]

If you have a tune from anyone, the converter is always locked at WOT, period.

You mean unlocked at WOT, I presume?!

For all step-ratio automatic transmissions with a torque converter (regardless of manufacturer), the converter is unlocked as you step into the throttle. With a "tune", either (A) this converter unlock will be scheduled earlier; or (B) converter clutch lock-up will be inhibited up to a certain vehicle speed.

The purpose of the torque converter is to multiply torque. By tipping further into the throttle, you signal the powertrain control system that you are demanding more torque, hence the converter clutch is unlocked to meet that demand. Tip in further, and you will get a kickdown shift (assuming you're not already in 1st gear).

I am an engineer for FoMoCo in the automatic transmission area.

[crouse]

Meteorite, Can you comment on the WOT OD shift? Can or should it be done?