TH400 + Boost + stock valve body/vacuum modulator = wont shift right
#1
TH400 + Boost + stock valve body/vacuum modulator = wont shift right
This is the first time i've ever used a stock valve body in an automatic and wanted to try having a car actually shift automatically.
This is a complete rebuilt TH400, stock valve body with a Transgo valve body recalibration kit.
If I leave it in drive it hits the rev limiter and takes a few seconds to shift.
On 8psi of boost it shift late and wants to do this. On 14psi its wont shift till i let off and get back into it.
Ive ordered the Transgo boost check valve but hasnt showed up yet.
Will this likely fix it? Im kinda skeptical. Can anyone share what else might need to be done? Ive read people talking about doing other things to get these to shift under boost but they didnt actually say.
This is a complete rebuilt TH400, stock valve body with a Transgo valve body recalibration kit.
If I leave it in drive it hits the rev limiter and takes a few seconds to shift.
On 8psi of boost it shift late and wants to do this. On 14psi its wont shift till i let off and get back into it.
Ive ordered the Transgo boost check valve but hasnt showed up yet.
Will this likely fix it? Im kinda skeptical. Can anyone share what else might need to be done? Ive read people talking about doing other things to get these to shift under boost but they didnt actually say.
#2
The transgo boost check valve should fix your problem. Reason being, the vacuum modulator normally has vacuum affecting it but with boost pressure, it must be bled off under high boost conditions which is what this check valve does.
#5
The TransGo recalibration kit runs into issues on the TH400 at 500 or more HP, so that's your first problem.
You may need two of the check valves in line to bleed off pressure and make it work right.
You may need two of the check valves in line to bleed off pressure and make it work right.