Driving a RMVB t400 - downshifting
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Driving a RMVB t400 - downshifting I have a new tranny to install this coming week, rmvb t400 w/ transbrake. I been told and read I will not be able to downshift - or rather its not a good idea.
How bad is it driving on the street? Or do you guys just trailer it to the track? lol
Small price to pay to never have to worry about breaking another POS 4L60E.
How bad is it driving on the street? Or do you guys just trailer it to the track? lol
Small price to pay to never have to worry about breaking another POS 4L60E.
I am having the same tranny put in and though it isn't in yet and I can't say from personal experience. I am 99% sure it is fine to drive on the street. I don't see why downshifting is a problem? If it is I hope some one chimes in to explain. As far as I know downshifting a th400 isn't a big deal just with the 4l60e it is.
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I was told by my builder that its a no-no to downshift it......something to do w/ the RMVB Transbrake setup. I hope its not too much of a hassle to drive on the street - a little hassle I can deal w/. I just would like to drive on nice days to meet the other fbodies in the area or to drive to the track.
When down shifting a RMVB in a TH400 it like free wheels,car will go to a idle like pushing in a clutch.This in turn wears the clutches as they rub alittle while this is happening.So when down shifting ease into the throtttle to engage the gear instead of free wheeling it
BTLFEDSS
BTLFEDSS
ill down shift mine only from 3 to 2 when going very slow like around conners, i have a full spool so it is less then 10mph i dont ever shift into 1st unless im stoped or almost stoped, like rolling
I drive a rmvb th400. I also built it.
The problem is that they have no front band to slow the direct drum when you downshift while coasting. You don't want a band because if you ever needed to get to neutral at high speed it would lock the tires up when you hit first.
The reason you shouldn't downshift while coasting is because the direct drum can spin very fast, it can break apart and come through the case and even through the floor into the car, most commonly it'll spin the oil off the intermediate sprag or roller clutch and damage it due to lack of oil.
There is no reason to downshift it to coast. You can downshift it and accelerate.
And from other post I've seen on this subject you don't need to be paranoid to drive it. Just upshift and downshift around the point an automatic would normally shift and don't coast at high speed in a low gear.
The problem is that they have no front band to slow the direct drum when you downshift while coasting. You don't want a band because if you ever needed to get to neutral at high speed it would lock the tires up when you hit first.
The reason you shouldn't downshift while coasting is because the direct drum can spin very fast, it can break apart and come through the case and even through the floor into the car, most commonly it'll spin the oil off the intermediate sprag or roller clutch and damage it due to lack of oil.
There is no reason to downshift it to coast. You can downshift it and accelerate.
And from other post I've seen on this subject you don't need to be paranoid to drive it. Just upshift and downshift around the point an automatic would normally shift and don't coast at high speed in a low gear.
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From: so cal
depends on the valvebody. some do put the manual low features in, some do not. if they don't then you can't what will happen is the internals will free wheels and you accidentally get back in the throttle the freewheel goes to an instant hold. if you do this at too high an rpm i have seen th 350 case split straight down the center. either ask the builder or the easiest way is to take off then when your in 2nd and first, when you let off it should feel like a stick shift when you forget to put your foot on the clutch, that grab feel. if you have the grab feel it will be alright to downshift, if not i wouldn't recomend it.
Originally Posted by ls1408cp
so say I was on the dyno and the motor was still spining crazy rpms when I let off the gas does that mean I have front band or what ever the hell you guys are talking about
I don't think anyone builds a REVERSE manual vb transmission with a front band.
If your street driving the vehicle there are times when you have no choice.
I have a Rossler TH400 with RMVB and a 4k stall with wimpy 2.73 gears for now (I blew the 3.73 gears and had a 2.73 rear sitting out back) will be installing a 12 bolt come spring.
With the 2.73 gears its hard just cruising stoplight to stoplight in these small towns to get into 3rd gear and if your cruising in second and come up on a red light you let out and then the light turns green before you come to a complete stop so you give it gas again.
Honestly I have been doing all kinds of bad things since I have been getting used to driving the RMVB, like starting in third because I forgot to shift it back to first.
Cruising in third about 40 and have someone come up beside me and want to play.......I just can't resist dropping it into second (theres no engine braking so they don't know I dropped a gear) and jamming the throttle.
I don,t abuse it and I don,t do anything that I would not do with a stock auto tranny, no running along at 60 MPH and dropping into first or crazy stuff like that.
I believe if I was hurting it that it would show in the tranny fluid and it still looks and smells brand new.
Thats what I love about this transmission, if I had driven the way I have with the TH400 with a 60E it would be dead already.
I have a Rossler TH400 with RMVB and a 4k stall with wimpy 2.73 gears for now (I blew the 3.73 gears and had a 2.73 rear sitting out back) will be installing a 12 bolt come spring.
With the 2.73 gears its hard just cruising stoplight to stoplight in these small towns to get into 3rd gear and if your cruising in second and come up on a red light you let out and then the light turns green before you come to a complete stop so you give it gas again.
Honestly I have been doing all kinds of bad things since I have been getting used to driving the RMVB, like starting in third because I forgot to shift it back to first.
Cruising in third about 40 and have someone come up beside me and want to play.......I just can't resist dropping it into second (theres no engine braking so they don't know I dropped a gear) and jamming the throttle.
I don,t abuse it and I don,t do anything that I would not do with a stock auto tranny, no running along at 60 MPH and dropping into first or crazy stuff like that.
I believe if I was hurting it that it would show in the tranny fluid and it still looks and smells brand new.
Thats what I love about this transmission, if I had driven the way I have with the TH400 with a 60E it would be dead already.
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thanks man, I guess I will have to find out first hand in a week or 2 when I get it back in.
I'll be running my stock rear for a little while longer (2.73's) the turbo seems to like the gear......we'll see how it likes the 4k stall too.
I'll be running my stock rear for a little while longer (2.73's) the turbo seems to like the gear......we'll see how it likes the 4k stall too.
I drive mine around.. when coming to a stop I don't downshift the car until the car is stopped. The way mine is set up is that if I do shift it from 3rd to 2nd it won't actually downshift until I give it some gas, or come to a complete stop, same as 2nd to first. I don't generally find it nessassary to downshift the car unless coming to a stop anyway, 1st is good to about 15, 2nd gear is good from about 15 to 35, anymore then that I put it in 3rd just to try to keep the noise down a little LOL.
I just wouldn't go shifting the thing all the time, if you can just get moving and leave it in 2nd or 3rd, and don't shift down until you're stopped, you're not gonna hurt anything. I wouldn't go flooring it in 1st and coasting it either... as long as you stick to those rules you shouldn't be putting much wear on anything really
I just wouldn't go shifting the thing all the time, if you can just get moving and leave it in 2nd or 3rd, and don't shift down until you're stopped, you're not gonna hurt anything. I wouldn't go flooring it in 1st and coasting it either... as long as you stick to those rules you shouldn't be putting much wear on anything really
