Can the vacuum control Valve be deleted if using an adjustable Vacuum modulator?

[Squibbly]

I'm sure everyone here is familiar with the vacuum control valve that controls the vacuum to the transmission vaccum control module to adjust your shift points.

From TM -34 Pg. 249



Can this item be bypassed and a direct connection be made from the vacuum pump to the modulator if the modulator is an adjustable one?

If not, why not?
I'm going to assume that having BOTH, the VRV hooked up and an adjustable VCM is probably going to make the entire -34 VRV adjustment procedure null.
If that is the case can someone point me to a "verified" OG approved VCM that is non adjustable?

Thanks.

-Squib

 

[87cr250r]

The VRV and modulator work together to set trans pressure relative to engine torque. Without the VRV you would have one trans pressure over all conditions which would result in two results. You will have hard late shifts at part throttle or slippery early shifts at full throttle.

If you use an adjustable modulator, set the VRV first to get the correct shift timing and then use the adjustable modulator to fine tune the firmness of shifts.

 

[cucvrus]

I bought a few CUCV's over the years that had the VCV bypassed, and it always resulted in indecisive shifts and slipping in and out of gear during the shifts. Most times when I had the VCV replaced and correctly programmed the transmission clutch bands had already suffered burnt clutches and a slight slipping on hard acceleration. I never ventured to rebuild an automatic transmission and at this point i have lost all my friends that did that kind of work. I am a cautious man when it comes to paying to have components rebuilt. I see the kit they install in the transmissions and the kit may cost a few hundred dollars and they charge you a few thousand dollars to install it. No thank you. I have 2 more CUCV's to complete and both have had the TH400 rebuilt so at this point I am set for the remainder of my hobby. I have a few take out TH400 transmissions and would only use them as cores for rebuilding if I were to find an honest rebuilder in my area. I would recommend getting the VCV and having it set up to shift properly.

The 1987 CUCV M1028 I drive has 98K miles and I can basically floor it when I pull out and it shifts perfect just like day 1 when it had 21K on it 25 years ago. The body, paint, seat is terrible, but the truck runs bone stock like a Swiss watch. This is true of all the CUCV's I ever owned.

The CUCV is nothing more than what it was intended to be. Heavy duty, reliable simple transportation. Good Luck. Fix it right the first time and most times money is a good tool to have the issue fixed professionally. And beware of short cuts and modification that are not needed. Many people claim to be mechanics, and many are NOT. I am NOT a mechanic and venture out to find qualified people to do the work that I want done right the first time. Throwing money at things is not an improvement of the overall design, function or reliability of the CUCV. In the end it is still just that a CUCV. I never seen a High-Country edition CUCV. Have a Great Day.

 

[ezgn]

I bought a few CUCV's over the years that had the VCV bypassed, and it always resulted in indecisive shifts and slipping in and out of gear during the shifts. Most times when I had the VCV replaced and correctly programmed the transmission clutch bands had already suffered burnt clutches and a slight slipping on hard acceleration. I never ventured to rebuild an automatic transmission and at this point i have lost all my friends that did that kind of work. I am a cautious man when it comes to paying to have components rebuilt. I see the kit they install in the transmissions and the kit may cost a few hundred dollars and they charge you a few thousand dollars to install it. No thank you. I have 2 more CUCV's to complete and both have had the TH400 rebuilt so at this point I am set for the remainder of my hobby. I have a few take out TH400 transmissions and would only use them as cores for rebuilding if I were to find an honest rebuilder in my area. I would recommend getting the VCV and having it set up to shift properly. The 1987 CUCV M1028 I drive has 98K miles and I can basically floor it when I pull out and it shifts perfect just like day 1 when it had 21K on it 25 years ago. The body, paint, seat is terrible, but the truck runs bone stock like a Swiss watch. This is true of all the CUCV's I ever owned. The CUCV is nothing more than what it was intended to be. Heavy duty, reliable simple transportation. Good Luck. Fix it right the first time and most times money is a good tool to have the issue fixed professionally. And beware of short cuts and modification that are not needed. Many people claim to be mechanics, and many are NOT. I am NOT a mechanic and venture out to find qualified people to do the work that I want done right the first time. Throwing money at things is not an improvement of the overall design, function or reliability of the CUCV. In the end it is still just that a CUCV. I never seen a High-Country edition CUCV. Have a Great Day.

My two cents, you definitely are a good mechanic, nobody knows it all about anything, but in terms of being a mechanic, you certainly are a good mechanic, case closed.

 

[Squibbly]

I bought a few CUCV's over the years that had the VCV bypassed, and it always resulted in indecisive shifts and slipping in and out of gear during the shifts. Most times when I had the VCV replaced and correctly programmed the transmission clutch bands had already suffered burnt clutches and a slight slipping on hard acceleration. I never ventured to rebuild an automatic transmission and at this point i have lost all my friends that did that kind of work. I am a cautious man when it comes to paying to have components rebuilt. I see the kit they install in the transmissions and the kit may cost a few hundred dollars and they charge you a few thousand dollars to install it. No thank you. I have 2 more CUCV's to complete and both have had the TH400 rebuilt so at this point I am set for the remainder of my hobby. I have a few take out TH400 transmissions and would only use them as cores for rebuilding if I were to find an honest rebuilder in my area. I would recommend getting the VCV and having it set up to shift properly.

The 1987 CUCV M1028 I drive has 98K miles and I can basically floor it when I pull out and it shifts perfect just like day 1 when it had 21K on it 25 years ago. The body, paint, seat is terrible, but the truck runs bone stock like a Swiss watch. This is true of all the CUCV's I ever owned.

The CUCV is nothing more than what it was intended to be. Heavy duty, reliable simple transportation. Good Luck. Fix it right the first time and most times money is a good tool to have the issue fixed professionally. And beware of short cuts and modification that are not needed. Many people claim to be mechanics, and many are NOT. I am NOT a mechanic and venture out to find qualified people to do the work that I want done right the first time. Throwing money at things is not an improvement of the overall design, function or reliability of the CUCV. In the end it is still just that a CUCV. I never seen a High-Country edition CUCV. Have a Great Day.

What speeds does your M1009 shift at Rick?


Sent from my iPhone using Tapatalk

 

[cucvrus]

My M1009 would shift to second at about 25 and third at about 40. The M1028 shifts at different speeds it just depends how hard I have my foot pressing on the vertical pedal. I like to push hard, and it shifts perfect anyway I drive it. But on the M1028 anything over 50 and it will not down shift. That is normal with the 456 gears. Crickets and katydids are in the air when I drive on the interstate. I can hear them everywhere all year round at 70 MPH in an M1028. And I don't want to hear it is hard on them. I done it for 30 years + and never had any issues. Not the most fuel efficient but then again, I don't drive full size pick-up trucks because I am concerned with fuel economy. Have a Great Day. I have a lot of firewood I need to stack.

 

[Squibbly]

My M1009 would shift to second at about 25 and third at about 40. The M1028 shifts at different speeds it just depends how hard I have my foot pressing on the vertical pedal. I like to push hard, and it shifts perfect anyway I drive it. But on the M1028 anything over 50 and it will not down shift. That is normal with the 456 gears. Crickets and katydids are in the air when I drive on the interstate. I can hear them everywhere all year round at 70 MPH in an M1028. And I don't want to hear it is hard on them. I done it for 30 years + and never had any issues. Not the most fuel efficient but then again, I don't drive full size pick-up trucks because I am concerned with fuel economy. Have a Great Day. I have a lot of firewood I need to stack.

Well then, mine is actually already set. I was trying to lower the shift speed but it looks like we both have it in the same place. Thanks, Rick.