for all autos (specifly the TH 400)
so like a budie was telling me that an auto will shift advenctuly in to 2nd eaven if the shifter is in "1st." I read the factory manual and it says it wont shift unless you move it to 2nd or "D" is this the whole point of a manual valve body.?

my TF 727 will let you nuke the motor b4 it will shift....if you have it held in 1st. new chevy tucks and such will shift into 2nd if you have it in first...i guess as a safety thing. i dont know about the TB400 proly not.

Chris G.

My C6 won't shift outa 1st (had a couple mishapps ;) ), it'll also shift into 1st when it shouldn't (big long downshift shirps, screemin engine)
A buddies TH350(in a jeep) will shift outa first when he keeps it in 1st. When downshifting he can shift into 1st on the hiway, it won't kick down till hes doin 40Km's (not sure when actualy, but its real tame/lame).

Your buddy is very wrong. "Specificaly" the TH400 WILL NOT shift automaticaly if its in "1".

The main purpose of a manual valve body is to provide more positive shifting (done manualy) at any RPM and load range.

Originally posted by Ramstein
Your buddy is very wrong. "Specificaly" the TH400 WILL NOT shift automaticaly if its in "1".

that's funny because my stock th400 will shift out of first if i have it locked down in 1st. now granted i have to have it wrapped out pretty hard to get it to do it and the motor definately does not need to reach any higher rpm's, but it will shift out of first.

Our Aussie built commodores that run the T700R will shift out of first even when the stick is locked back in first and i have also driven a few cars fitted with T400s that do this also.

A turbo 400 will shift on its own when pulled into low gear, the governer will overide the manual shift to protect the motor from going:nuke: . Remember this trans was made for industrial aplications for drivers that hate there job. As a side note this can be made as an advantage, when I used to drag race I had my 400 set up so that I didn't have to shift, it would shift a 6200 every time so it has its advantages.

turbo 400's are set up to shift on their own. you can buy a 50 buck kit to stop them from doing that but like they said above they were built to be idiot proof.

the t727 and the t999 will not shift unless you shift them out of first. now shifting down from 2nd to 1st when slowing i dont know if this is with the rest but mine will only shift when its slow enough not to redline the motor. aka built in shift points. if you pull it all the way down it will act like its in neutral until its where it will safely shift.


DP

Originally posted by Dust Puppy

the t727 and the t999 will not shift unless you shift them out of first.

The 904 is the same (for reference here)

Originally posted by Dust Puppy
the t727 and the t999 will not shift unless you shift them out of first.
DP

You're right on the 400 but wrong on the 727 (and I don't know about the 999). Also the C6 will shift on its own.

Depends on your linkage & rebuild. I know any number of guys running TH400's that will NOT shift outta first regardless of RPM if the shifter is in 1st. I've owned just one TH400 in my life & it was stock. If I put it in 1st, it stayed there. Period. Ditto for every TH350 I've ever had & the one TH700 I had.

Incidentally, it's my understanding (NO 1st hand knowledge) that if you put a C6 in "2" it will take off in 2nd rather than launching in 1st & then shifting. Anyone want to confirm or deny that one???


TEX

Would it not SUCK big time to have the tranny shift outta first on a big steep downhill, when the revs are high and you´re relying on motor braking?? Or doesn´t it happen in these situations??

A stock C6 or 727 (at least the ones I have/had) put in 2 takes off in 2 and stays there until you wind it hard - never goes to 1 but will blow out to 3. One of these locked in 1 will eventually blow out into 2 and then 3. At least one owners manual stated that this (2nd gear takeoff) was for ice/snow; reducing torque to the wheels should allow you to take off gently instead of just spinning when the converter unloads. Interesting that it seems there were different versions of the 400 from looking at what's posted here. Can't determine on my 4L60E because the engine has an electronic rev limiter built into the ignition system.

Yeah it sucks for the thing to do that on steep downhills. Imagine a few tons of hay on a long downgrade with brakes on fire and 90 mph in "1st gear" - someone I know did this. I converted my 727 with a B&M transpak because I'd rather risk the engine than lives.

Originally posted by billj
Would it not SUCK big time to have the tranny shift outta first on a big steep downhill, when the revs are high and you´re relying on motor braking?? Or doesn´t it happen in these situations??

man i really have to get the rpm's high to get the thing to shift....i mean really high! i would have to be hammering the gas down the hill to get it to do it. no it does not shift going down the hills.

So it seems like the tendency to shift out of first is a setup thang, depending on linkages and shite?!?!?!

Originally posted by Dust Puppy


now shifting down from 2nd to 1st when slowing i dont know if this is with the rest but mine will only shift when its slow enough not to redline the motor. aka built in shift points. if you pull it all the way down it will act like its in neutral until its where it will safely shift.


DP

mine will shift down at (about 30 or 35mph) speed when it does look out! it will bark the tires and throw you into the windsheild!:eek:

Chris G.

Stock truck 400 will shift around 5600 rpm regardless of where the shifter is.

A C-6 will start in 2nd if shifted into second. So will any auto with a manual valve body or an electronic controled trans with the proper programing

Originally posted by High5


that's funny because my stock th400 will shift out of first if i have it locked down in 1st. now granted i have to have it wrapped out pretty hard to get it to do it and the motor definately does not need to reach any higher rpm's, but it will shift out of first.

I stand corrected! I just checked it out and only some 400s (in camper special trucks) would hold the gear.

I learn more about how little I think I know everyday :p

Originally posted by Ramstein


I stand corrected! I just checked it out and only some 400s (in camper special trucks) would hold the gear.

I learn more about how little I think I know everyday :p

cool cuz mine is out of a camper special

mine came out of a 1 1/4 ton military ambulance. it was one of the full size chevy cuccv's but had a ambulance bed on it. anyway....

I've had Stage 1, 2 and 3 shift kits in Turbo 400's. All but the stage 3 allowed the governor to shift the tranny, vacuum hooked up or not. I wonder what the identifiable differences are from a Camper Special vs. a run of the mill TH400?

have you added a manual valve body, or are you simply trying to shift it manually?
a stock th400 will shift out of first by it self, then down shift again when you back out of it. but if you add a manual valve body it will not shift by itself