355z28

iTrader: (8)

Id assume so, my other trans builder before I went to flt instructed me the same way. Said the OD only applys a few things and tends to toast them.

senicalj4579

iTrader: (41)

Theres many threads about drag racing od vs d? I cant find them. Sorry,but I wasnt there thread upon thread to talk about it like you... and I searched. I even searched google...and I wasnt satisfied. So I posted. Is that ok with you almighty god sir?

Predator T/A

iTrader: (7)

the best thing about driving it in D i the extra support the low roller clutch and the forward sprag gets by the low reverse clutches coming on and the ovverun clutches coming on which do not come on in OD range. running in D range basically gives the hard parts more support to handle the load.

Jays_SSZ28

iTrader: (2)

I'd like to know whats going to happen if a WOT 3-4 shift is made.
As usual a bunch of people use the generic 'it'll burn your transmission up' without getting into specifics.

Anyone have anything specific, because honestly I know this is bullshit.
This is ONE time I made a video of me doing it, http://www.youtube.com/watch?v=Eb4DUGWhAqM
I've done it several times since, in fact I lost it once and did a 360 going to WOT at 90 mph. It went sideways at 130, it did a 180 at some point and went backwards around 80 to 60mph then did another 180 and kept going after I restarted it.

I later got my converter restalled and tore the trans down for inspection since it was out, and found nothing wrong.

I built it. It has a stock width BW hi energy band, stock servo, plugged 4th accumulator feed. It's got the 3-2 valve blocked to shorten the 3rd circuit. And a few other things.

D will apply the over run clutches which helps the forward sprag hold, thats it. The low roller holds in 1st in 1, 2, D, OD. Whenever it's in 1st no matter the gear selected.
Some builders are using the Sonnax valve that applies the over run clutches in OD. Other than that, how many 3-4 upshifts does it take, and why hasn't my build failed.....

Predator T/A

iTrader: (7)

the low reverse clutches come on also in manual low and support the low roller clutch look at the fluid diagram for manual 1st here.
WOT in 4th is not good it creates too much heat in the trans due to the converter rememebr the converetr is the #1 heat source in the trans with the pump being next. also due to the load that is placed on the trans in 4th on a mtor with modearte torqe it is possible for it to start driving through the band. you may not have any problems doing it but down the road you will. unless the trans is built for this IE wide band and servos and band clearnce you take the chance of smoking the band on a stock weight car with moderate torque. its not to bad on it when it shifts at 130mph because you have enough speed howevr shifting at lower mph is where the prob is however you will still create too much heat in the higher MPH also

Jays_SSZ28

iTrader: (2)

Finally some credible information. Good stuff, thanks.

senicalj4579

iTrader: (41)

so I guess I should be drag racing in d?

Predator T/A

iTrader: (7)

it is safer, the low reverse clutches ony come on in reverse normally these clutches are stronger than the low roller by themselves which is holding in 1st the clutches are splined to the planet gear set that the low roller clutch is holding and does the same job they will come on in manual 1st along with the low roller holding and help support the low rooler clutch. In the input drum there are 2 clutches call ovverun clutches theyare not that strong because there are only 2 of them these normall give you engine breaking and are not applies however they are splined to the driven side of the sprag and will by themsleves in the event of a forward sprah failure drive the vehicle home in most cases if you manual shift it because again they come in manual range. So while weak in size and quantity they do help support the forward sprag. what i normally did was start in manual 1st in case i spun so it wouldnt short shift and then once i got going throw it in D and let the computer do what it does

Predator T/A

iTrader: (7)

as far as you spinning the manual range and all is not going to give you more power howevr it may let you put more power to the ground if say your low roller is chattering or the forward sprag is chattering causing you to lose torque to the ground from slippage

lemons12

iTrader: (71)

PredTA... Any insight on why most people hit the limiter when in drive and not in OD? My last white TA did it EVERY time it was in D at the track.

Predator T/A

iTrader: (7)

on a no-built tran there are more things happening when in D hydraulically so there may be a little more shift delay with a higher HP motor. there are ups and downs to each of them. when in manual D range first the ovverun clutches are on however they have to go off in second and then back on in third, at the same time the band is being pushed off in third by the third gear oil and the ovverun clutches are coming back on. so alot hydraulically is happening which can overload a stockish unit with no upgrades

lemons12

iTrader: (71)

MAkes sense... That setup was around 430Rw stock trans.. This one has a built trans and no slipping.

Predator T/A

iTrader: (7)

this is why the tolerances and pack clearnces are setup tighte on a built unit amongst other reasons, let piston travel creates a faster cleaner shift and doesnt crete a hammer effect on the parts with higher pressures

Joshiedoom

iTrader: (4)

ive raced back to back going from D to OD to D and it doesnt change my time what so ever... I have never manually shifted though

StuntmanMike

iTrader: (2)

I thought these didn't shift into 4th at WOT anyway?

I just leave mine in OD, IIRC. As I understand it, leaving it in D just locks out 4th (OD), but like everyone else said, you don't get up to a speed where it would need to shift into 4th anyway, plus I don't think it could even if it wanted to, since I don't think it'll shift into 4th at WOT.

I rememeber with my '88 GTA, after I pushed the pedal down so far it would automaticvally kick down into 3rd, fastest I oculd get that car 115-ish or so, then it would shift out of OD and the motor would redline.

Jays_SSZ28

iTrader: (2)

The stock programming in the picture below shows how these cars will do a WOT 3-4 shift in stock form.


Thats because the stock 700R4 tv sleeve wouldn't let it. Just about every trans company makes a sleeve to allow WOT in 4th on those.

Predator T/A

iTrader: (7)

on the 700s you could put a vette governor or a 2.8? the v6 governor in the trans and it would shift to 4th at wot though

PBA

The stock 4L60E's when in "D" shifter position do not have the overrun clutches on till you get into 3rd gear. That is why with a stock setup you use the "OD" shifter position when racing, as the 2-3 shift will not rob you of any shift oil going to the overrun clutches. This will allow a better 2-3 WOT shift. The 2-3 shift when in the "D" shifter position will bring on the overrun clutches on the 2-3 shift, not what you want to happen here. If you want to use the "D" shifter position when racing, then add the Sonnax HD 2-3 shift valve to your valve body. This will allow you to use "D" and the overruns will be on in all three shifter positions, 1, 2, or 3 just like the 700R4. If you manually shift it, the overrun clutches will be on all of the time.

Side note: The stock 4th apply servo is almost identical in apply area as the Corveete servo. So if you block or limit the 4th accumulator and increase the apply feed hole size in the separator plate, you should have no problems with a 3-4 WOT shift, if you decide on making one.

jakeshoe

iTrader: (14)

Another side note about blocking oil to the backside of the 3-4 accumulator.
There is a "pee" hole that sprays oil on the planets, it is better to block the accumulator from traveling than to kill the oil going to it.

Jays_SSZ28

iTrader: (2)

I've heard at least one builder who blocks the 4th accumulator feed and leaves the piston out. I guess accumulator oil would go out the bleed hole and spray the planet area.
Any thoughts on that?