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just be careful with launches, low traction scenarios, and if you want to extend its life, i would put a auxillary trans cooler with a magnetic filter before it or the radiator end tank one(depending if you just bypass it or use it in conjunction, you want to keep metal out of the thing) and a new modulator
The modulator is the vacuum controlled gizmo on the front of the transmissio if standing in front of the radiator looking down in the engine bay. it should have a connection to manifold vacuum.
The reason I say replace is fun things happen if the diaphram breaks now this is beside the quadrajet on a 1977 small block buick (V8, its what the V6 and 3.8 and 3800s come from lineage wise ) and the transmission is a RWD th350, but the modulator is the same for TH350, TH400, 440-T4(your transmission before it was electronic, 1990 was last year. it was also called 4t60. ) 4t60e, which you have, 1991-1998 or 1999 in some apps I think. Uses a modulator still, despite being electronic controlled (no TV cable on a 4t60e) it controls line pressure (modu)
Thanks for the info. I’ve never checked that modulator out besides the vacuum lines going to it. I’ll definitely test it and make sure it’* still working properly. You sure know your stuff about theses Buicks
Thanks for the info. I’ve never checked that modulator out besides the vacuum lines going to it. I’ll definitely test it and make sure it’* still working properly. You sure know your stuff about theses Buicks
No, its simply a if its original, get a new one
I dont think you understand quite at this moment the severity of why I say this, lol,
Imagine this modulator. always has had vacuum applied to it.
Its old. the diaphram had to keep vacuum(air) separated from ATF. trans has some good mileage and some new ATF,possibly different chemicallyl than the OE even.
And now you got that diaphram having to separate Pressure. and vacuum. rapid shifts from either, and age and heat Etc..
If it wasnt recent few years or high quality, I would replace it no matter what. they can be had decent and they are easily adjusted too.
If it wasnt old there are functional ways to check it which is good but I doubt its newer lol
No, its simply a if its original, get a new one
I dont think you understand quite at this moment the severity of why I say this, lol,
Imagine this modulator. always has had vacuum applied to it.
Its old. the diaphram had to keep vacuum(air) separated from ATF. trans has some good mileage and some new ATF,possibly different chemicallyl than the OE even.
And now you got that diaphram having to separate Pressure. and vacuum. rapid shifts from either, and age and heat Etc..
If it wasnt recent few years or high quality, I would replace it no matter what. they can be had decent and they are easily adjusted too.
If it wasnt old there are functional ways to check it which is good but I doubt its newer lol
Alright thanks. I’ll look into getting a new one. As far as I know it’* original.
A bad modulator can also serve as a path for all of the transmission fluid to get sucked into the engine and digested until the pump sucks air and bad things happen.
Thanks for the info. I’ve never checked that modulator out besides the vacuum lines going to it. I’ll definitely test it and make sure it’* still working properly. You sure know your stuff about theses Buicks
@CathedralCub HERES a rare situation that it was indicated it was happening. it was siphoned/puled into engine but the car sat and the ATF Made it out of hte threads I presume
@CathedralCub HERES a rare situation that it was indicated it was happening. it was siphoned/puled into engine but the car sat and the ATF Made it out of hte threads I presume
Usually this is accompanied by a sluggish transmission reaction to throttle position, while the engine reacts just fine while lugging and/or revving longer than normal awaiting the needed gear change.
This isn't just on the 4T60, it'* on just about anything with a vacuum modulator. It'* harder (therefore slower) for vacuum to pull the plunger and for the spring to return it if there'* transmission fluid where extra-thin air is supposed to be.
Usually this is accompanied by a sluggish transmission reaction to throttle position, while the engine reacts just fine while lugging and/or revving longer than normal awaiting the needed gear change.
This isn't just on the 4T60, it'* on just about anything with a vacuum modulator. It'* harder (therefore slower) for vacuum to pull the plunger and for the spring to return it if there'* transmission fluid where extra-thin air is supposed to be.
Yes, the 4t60(E) and 3l80(th400), 4l60, TH200m, etc use the same modulator
important to remmeber to get a new check valve on the cruise and/or purge valve vacuumo which would ensure that cruise or modulator vacuum signals dont cross paths too
) and the transmission is a RWD th350, but the modulator is the same for TH350, TH400, 440-T4(your transmission before it was electronic, 1990 was last year. it was also called 4t60. ) 4t60e, which you have, 1991-1998 or 1999 in some apps I think. Uses a modulator still, despite being electronic controlled (no TV cable on a 4t60e) it controls line pressure (modu)
