TH400 Question - Early Shifting
07-15-2008, 01:48 PM
#1
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TH400 Question - Early Shifting I have a TH400 on my 03 Silverado. As far as i know, it is completely stock. I have the modulator hooked up to the vacuum directly to my intake. The problem is that when I manually shift the tranny, from 1st to 2nd it will still shift on its own. It usually shifts at around 4,800-5,200 RPM. From 2nd to 3rd, It will hold the shift up to when I shift it (about 6,200). I dont have the kickdown solenoid hooked up cause that only made it worse at WOT. I do have a 4,500 stall on it tho.
Is there a way to get it to shift when I want it to without having to get it built w/a manual valve body?
Is there a way to get it to shift when I want it to without having to get it built w/a manual valve body?
07-15-2008, 01:56 PM
#2
I have a manual/automatic vb in my old school. You can leave in drive to let it shift its self or manually shift it and it will hold any gear until you shift. You can buy the complete vb for cheap if you look around. Look for Manual/Automatic vb. Just have to swap it out with the stocker.
07-15-2008, 02:06 PM
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I see, so with this manual/auto VB does the tranny have to be built? I dont want a transbrake or RMVB. If i leave my stock one to shift on its own (3rd) it shifts fine accordingly to my speed.
07-15-2008, 03:23 PM
#4
Not my picture.
You can take the 1-2 shift valve out and grind two flats in it and plug the hole in the VB to prevent it from shifting 1-2 on it's own.
All shift kits have a modified 1-2 valve.
You can take the 1-2 shift valve out and grind two flats in it and plug the hole in the VB to prevent it from shifting 1-2 on it's own.
All shift kits have a modified 1-2 valve.
07-15-2008, 05:30 PM
#5
I have a TH400 on my 03 Silverado. As far as i know, it is completely stock. I have the modulator hooked up to the vacuum directly to my intake. The problem is that when I manually shift the tranny, from 1st to 2nd it will still shift on its own. It usually shifts at around 4,800-5,200 RPM. From 2nd to 3rd, It will hold the shift up to when I shift it (about 6,200). I dont have the kickdown solenoid hooked up cause that only made it worse at WOT. I do have a 4,500 stall on it tho.
Is there a way to get it to shift when I want it to without having to get it built w/a manual valve body?
Is there a way to get it to shift when I want it to without having to get it built w/a manual valve body?
07-16-2008, 01:23 AM
#7
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07-16-2008, 11:53 AM
#8
The picture above (mine), shows how to mod the VB to hold manual low gear.
The trans will not shift once this mod is done until you move the lever to 2nd gear. It will also shift to low gear if you pull it to low, no matter what the road speed or engine rpm.
For early shifts, you will have to modify the governor weights. I have an articel that describes how to do this using a package of nails from the hardware store for less than $1.
Or you can buy a kit to do it for about $30-40.
The trans will not shift once this mod is done until you move the lever to 2nd gear. It will also shift to low gear if you pull it to low, no matter what the road speed or engine rpm.
For early shifts, you will have to modify the governor weights. I have an articel that describes how to do this using a package of nails from the hardware store for less than $1.
Or you can buy a kit to do it for about $30-40.
