Hey guys,
I am hoping I can learn something from guys who deal with turbo motors and turbo hydramatic transmissions every day.
I have a fairly potent 4 cylinder turbo Volvo, and I'm running a 700R4 behind it. I have been having trouble getting the 3-4 clutches to live for very long. I'm thinking about trying a 2004R , but I think I need to solve an issue with TV valve adjustment first. And give this 700 one more shot.
So the problem is that I run a big turbo, and big throttle body. The combination of engine, turbo, throttle, etc. works together so that I can make almost full power from the engine with the throttle position somewhere around 50-60%. Shortly after I installed the 700R4, I had the following experience that tipped me off to this potentially destructive situation for the transmission.
I'm driving up a steep grade on interstate 70 in the Colorado mountains. I'm going about 50mph in 3rd gear. So I floor the accelerator pedal to encourage a downshift and crank up the horsepower to accelerate. The turbo spools, makes 25psi boost and the car takes off, usually spins the tires in 2nd if I do this. Its accelerating faster than I want in 2nd so I lift my foot to about 1/2 throttle. This only decreases the power a little bit. The turbo is still making 20+ psi boost, but the trans shifts quickly to 3rd. And instantly I realize this is a problem because its not the hard shift I get when I'm at full throttle. These part throttle shifts at high boost are quite soft, and the shift takes 1-2 seconds to compete, obviously slipping the entire time.
After about a month of driving with the new transmission, even though I try to avoid the above shift with driving style, the 2-3 shift has become pretty weak or just smokes the cluthces altogether if I"m making alot of power. This happens even with WOT and the TV cable buried against its stop. Its just dead now. The clutches are gone.
Is there a trick that you turbo/turbohydramatic guys use so that the transmission line pressure is at maxium if the manifold pressure is high? I know there is no vaccuum modulator, but that seems like what I need.
Some details on the engine/trans combo. I'll provide more if someone really
wants to dig in.
The motor makes about 500hp/525ft-lbs torque.
I built this transmission myself, my first one actually. I'm learning here.
The 3-4 clutch pack is a 9 disk setup, stock has 6 I believe. I also did alot of valve body modifications according to the Transgo 2&3 kit instructions, and also added a Transgo hi-rev kit. I think I know most of the details here, if you really want to know what I did. Though I'm not sure this is the problem. I do think that I have made a few high power shifts with reduced line pressure and this has killed the 3-4 clutches very quickly. I'm looking for a solution to this problem.
Thanks in advance and greetings! Hows that for a first post?
-Ken
I am hoping I can learn something from guys who deal with turbo motors and turbo hydramatic transmissions every day.
I have a fairly potent 4 cylinder turbo Volvo, and I'm running a 700R4 behind it. I have been having trouble getting the 3-4 clutches to live for very long. I'm thinking about trying a 2004R , but I think I need to solve an issue with TV valve adjustment first. And give this 700 one more shot.
So the problem is that I run a big turbo, and big throttle body. The combination of engine, turbo, throttle, etc. works together so that I can make almost full power from the engine with the throttle position somewhere around 50-60%. Shortly after I installed the 700R4, I had the following experience that tipped me off to this potentially destructive situation for the transmission.
I'm driving up a steep grade on interstate 70 in the Colorado mountains. I'm going about 50mph in 3rd gear. So I floor the accelerator pedal to encourage a downshift and crank up the horsepower to accelerate. The turbo spools, makes 25psi boost and the car takes off, usually spins the tires in 2nd if I do this. Its accelerating faster than I want in 2nd so I lift my foot to about 1/2 throttle. This only decreases the power a little bit. The turbo is still making 20+ psi boost, but the trans shifts quickly to 3rd. And instantly I realize this is a problem because its not the hard shift I get when I'm at full throttle. These part throttle shifts at high boost are quite soft, and the shift takes 1-2 seconds to compete, obviously slipping the entire time.
After about a month of driving with the new transmission, even though I try to avoid the above shift with driving style, the 2-3 shift has become pretty weak or just smokes the cluthces altogether if I"m making alot of power. This happens even with WOT and the TV cable buried against its stop. Its just dead now. The clutches are gone.
Is there a trick that you turbo/turbohydramatic guys use so that the transmission line pressure is at maxium if the manifold pressure is high? I know there is no vaccuum modulator, but that seems like what I need.
Some details on the engine/trans combo. I'll provide more if someone really
wants to dig in.
The motor makes about 500hp/525ft-lbs torque.
I built this transmission myself, my first one actually. I'm learning here.
The 3-4 clutch pack is a 9 disk setup, stock has 6 I believe. I also did alot of valve body modifications according to the Transgo 2&3 kit instructions, and also added a Transgo hi-rev kit. I think I know most of the details here, if you really want to know what I did. Though I'm not sure this is the problem. I do think that I have made a few high power shifts with reduced line pressure and this has killed the 3-4 clutches very quickly. I'm looking for a solution to this problem.
Thanks in advance and greetings! Hows that for a first post?
-Ken
