[gman398]

i have a 700 r4 it shifts fine in reverse but i forward you have to give it gas before it will go in gear and when it does it lunges forward any ideas what this could be

[302 Z28]

Is this a recent rebuild, or an old trans that has been operating for awhile?

Vince

[gman398]

Its a recent rebuild

[Crosley]

there is a pressure loss in the forward clutch section.

Possible problem in the input drum or the sealing rings or a cut lip seal or too much clutch pack clearance.

A pressure gauge attached to the main line port may reveal a problem if the pressure drops off when the trans is placed into "D"

[gman398]

thnks ill hook up and check the pressure thnks for your help will let you know
what i find

[buickelectra225]

i would suggest starting with easy fixes like checking line pressure and ensuring the throttle cable is connected and properly adjusted.on a 700r4 the throttle cable is the only input to the trans for throttle pressure,same as a 727 or 904 torqueflight.

being a transmission mechanic ive seen many mistery problems with easy fixes that are never found easy.you could have a cut seal when it was rebuild or a cut sealing ring a sticky valve or a bad/leaky valvebody.try checking throttle pressure and cable adjustment,then next would be cheap fix number 2 try some marvel mystery oil a small amount and a deadblow a couple times against the pan.if that doesnt free it up it may be a serious internal problem.

[tnsmith10]

Originally Posted by buickelectra225

i would suggest starting with easy fixes like checking line pressure and ensuring the throttle cable is connected and properly adjusted.on a 700r4 the throttle cable is the only input to the trans for throttle pressure,same as a 727 or 904 torqueflight.

being a transmission mechanic ive seen many mistery problems with easy fixes that are never found easy.you could have a cut seal when it was rebuild or a cut sealing ring a sticky valve or a bad/leaky valvebody.try checking throttle pressure and cable adjustment,then next would be cheap fix number 2 try some marvel mystery oil a small amount and a deadblow a couple times against the pan.if that doesnt free it up it may be a serious internal problem.

and just what is hitting the pan with a deadblow hammer going to do to fix this guys problem? i didnt know that breaking the filter would fix an internal hydraulic leak.
after over 20 years in the transmission industry i guess you learn something new every day...

[302 Z28]

Originally Posted by buickelectra225

being a transmission mechanic........ next would be cheap fix number 2 try some marvel mystery oil a small amount and a deadblow a couple times against the pan.if that doesnt free it up it may be a serious internal problem.

I think I know where you have worked .

Vince

[gman398]

checked pressure last night have 20 psi at idle but will go to 60 psi at a 1000 rpm, checked in reverse and drive same pressures

[SSedan64]

Originally Posted by gman398

checked pressure last night have 20 psi at idle but will go to 60 psi at a 1000 rpm, checked in reverse and drive same pressures

Pressures are definitely Low. Check all gears positions @1000-1200rpm at Minimum and Full TV cable pull.
Minimum--------Full
P=
N=
R=
O/D=
D=
2=
1=
Don't forget Parking Brake & wheel chocks.

[transbuilderguy]

Originally Posted by buickelectra225

i would suggest starting with easy fixes like checking line pressure and ensuring the throttle cable is connected and properly adjusted.on a 700r4 the throttle cable is the only input to the trans for throttle pressure,same as a 727 or 904 torqueflight.

being a transmission mechanic ive seen many mistery problems with easy fixes that are never found easy.you could have a cut seal when it was rebuild or a cut sealing ring a sticky valve or a bad/leaky valvebody.try checking throttle pressure and cable adjustment,then next would be cheap fix number 2 try some marvel mystery oil a small amount and a deadblow a couple times against the pan.if that doesnt free it up it may be a serious internal problem.

wow thats the first time i have heard that yeah lets break the aux VB along with the filter lol.....sounds like there is a pressure issue.....bad pump maybe pressure regualtor stuck....or maybe the pump output screen didnt get put back in and you are blowing the line pressure into the case just a few things