Can't DD A RMVB?
08-14-2009, 04:10 PM
#1
Can't DD A RMVB? I have done several searches, but have only seen this topic touched on, never gone in depth. So I figured I'd make a thread to get more details on this.
I read, in my quest for the right shifter, that you aren't suppose to downshift a RMVB, because it puts a constant load on the sprag. So what I'm gathering is that you can't DD a RMVB? I find this hard to believe because I know a few friends that DD their manual valve bodies. I want to DD my car during the summer months and what not, and I want to put a th400 in my car, and I know this means making sacrifices, but this seems a little extreme, even to my standards.
Can someone shed a little light on this topic please?
I read, in my quest for the right shifter, that you aren't suppose to downshift a RMVB, because it puts a constant load on the sprag. So what I'm gathering is that you can't DD a RMVB? I find this hard to believe because I know a few friends that DD their manual valve bodies. I want to DD my car during the summer months and what not, and I want to put a th400 in my car, and I know this means making sacrifices, but this seems a little extreme, even to my standards.
Can someone shed a little light on this topic please?
08-14-2009, 05:13 PM
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I didn't daily drive my T400 rmvb but it seen a good bit of street duty. I never did full throttle downshifts because I read the same stuff as you. The rmvb wasn't bad but the lack of overdrive was horrible. I ended up swapping to a 4l80e for this reason. The downside is that a 4l80e is probably at least double the price of a T400 for an initial install.
08-14-2009, 05:28 PM
#5
I didn't daily drive my T400 rmvb but it seen a good bit of street duty. I never did full throttle downshifts because I read the same stuff as you. The rmvb wasn't bad but the lack of overdrive was horrible. I ended up swapping to a 4l80e for this reason. The downside is that a 4l80e is probably at least double the price of a T400 for an initial install.
and I'm not taking any advice from you. I hear enough stories about you east brady type people and the water you guys drink. must be an upper allegheny thing......
08-14-2009, 06:26 PM
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i put about 30 miles on my 350 turbo today with a RMVB. you can shift out of 3rd into second or first. just let off the gas and shift, it will free rev until back on the gas.
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08-14-2009, 07:49 PM
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I think when rossler built my T400 he did a banded 2nd gear so I could downshift it. Does that make sense to anyone? When I would downshift it would seem like it was in neutral until I got back on the throttle.
08-14-2009, 08:31 PM
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Years ago it was stated that you don't want to down shift an auto trans for engine braking. Why it puts a lot of wear on the crank thrust bearing, and generates heat in the trans. This was with old school gen 1 stuff. I still wouldn't do it today. I do down shift my trans from OD to 3rd or 3rd to 2nd when I'm about to hammer down on the throttle. This is usally at lower rpms. i do this because of the way 4l60s have a mind of their own. I also shift into od at the end of the 1/4 mile to take the stress off of the motor.
08-15-2009, 10:51 AM
#13
The few things you need to consider are with downshifting mostly.
One problem, thats minor, and I've only seen it once came from a th400 with no front band. Every time the guy ran the 1/4 mile he'd put it in first to coast down. With no front band the direct drum over runs. In this peticular case it was slinging fluid off the intermediate sprag and it failed.
That guy got lucky, some people who drive at a high mph and throw it in first get the direct drum through the floorboard. It can explode.
As for daily driving it...I've seen threads on this were people are scared to death over bullshit.
If you have a RM th400 with no front band, just don't be stupid with it.
No high mph 0% throttle downshifting pretty much. If you're in the city driving under 70 mph and with limited distance, just get the manual shifts close to what they would be automatically, if they're not dead on so what.
Just don't get one with a roller clutch, and stop worrying.
One problem, thats minor, and I've only seen it once came from a th400 with no front band. Every time the guy ran the 1/4 mile he'd put it in first to coast down. With no front band the direct drum over runs. In this peticular case it was slinging fluid off the intermediate sprag and it failed.
That guy got lucky, some people who drive at a high mph and throw it in first get the direct drum through the floorboard. It can explode.
As for daily driving it...I've seen threads on this were people are scared to death over bullshit.
If you have a RM th400 with no front band, just don't be stupid with it.
No high mph 0% throttle downshifting pretty much. If you're in the city driving under 70 mph and with limited distance, just get the manual shifts close to what they would be automatically, if they're not dead on so what.
Just don't get one with a roller clutch, and stop worrying.
08-15-2009, 04:41 PM
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Rossler rocks. So far their 4l60 has been the best one that I,ve used. You can also now get a 4L80 with a FMVB so no more $$$ computer to run it.This will be my next trans. That or a Liberty. LOL
08-15-2009, 04:59 PM
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Go with a forward patter manual setup, that is what I run in my 400. Has much softer downshifts below wide open to allow you to actually use it driving up hills and what not. Unless I am coming up the big *** hill to my house I seldom ever have to downshift anyways just lean on the skinny pedal.
