nurse

I just had my TH400 built with all Coan racing parts including Forward drum and supersprag and Transbrake but i dont understand the whole dont downshift and worse still the big writing on the transbrake instructions that say " Dont neutral or downshift transmission during shutdown – Leave in high gear only'....now that is all well and good but i have a Twin Turbo LS1 and i dont really fancy letting it idle in high gear for a minute or so before shutting down.....am i gonna stuff my trans?I like to be able to drop my car back into second gear and light the tyres at 70mph...did i stupidly buy race only components?...i would not ask this question on our Aussie LS1 forum...I need USA input

Josh@KY-Turbo

iTrader: (120)

I was told not to down shift with out being under some throttle to keep the shock off the internals of the tranny.

stevewix

when you downshift to a lower gear it launches the internal parts of the tranny into the stratosphere regarding RPM. You aren't going to do any damage to the rotating assembly letting it coast down. For a greater explanation call Mikes in Lancaster, CA. He built my Ultimate Vasco 400 that is on it's 6th season without a rebuild, he can explain it better.

98turbls1

iTrader: (17)

I was also told that it's okay to downshift when you are under the stall speed. For example if you have a 4000 stall you have to wait until you are under that point...

8a8mfh

iTrader: (3)

You don't want to downshift off the throttle because a rmvb th400 has no front band to hold the direct drum and it will spin pretty fast, it can sling the lube oil off the sprag.

98turbls1

iTrader: (17)

So when you say "on the throttle" that means 1/8 throttle or does that mean more??

SuperZ

iTrader: (2)

I just come to a complete stop before I downshift but I would also like to know the rules on when I can and cant downshift.I have had all these dang bikes pullin up next to me lately and I wouldnt be able to do much in 3rd gear.

modracr62

iTrader: (12)

Do not downshift during shutdown in meaning do not downshift after reaching a high speed. Downshifting at a high speed off the throttle may possibly cause you to lose control of your car and will possibly damage parts....A reverse shift pattern will require you to downshift to get to neutral...

8a8mfh

iTrader: (3)

NOT TRUE!!!!!
Thats why they always leave the front band out with a RMVB!
The front band gives it engine braking and makes the engine rev/wheels slow down when downshifted. A RMVB trans should not have engine braking.

8a8mfh

iTrader: (3)

Enough to where it will pull (or move the vehicle forward) or close to it.

8a8mfh

iTrader: (3)

When I'm going 50 or so and want to roll race I can stomp the gas, throw it in first for a split second to get the rpm up, then hit second, then third.
You have to know your car well to be able to do this because mine will go sideways at 90+ when I do this.

kill_machine85

iTrader: (4)

Ive been told to not downshift while not on the throttle. But that its ok if its under your stall

nurse

Wow guys thanks for the response..i have no engine braking btw...I think i will still down shift because i cant resist droping my car back to second and lighting them up when it is required...and that is often

revtime

iTrader: (1)

What I have gotten from the whole debate is do not downshift after going through the traps at 1xx MPH.
I roll about 40 45 MPH and downshift to second and mash the throttle. I have not noticed any excessive wear doing this.

Carl Rossler built the tranny though and I could not tell you exactly what he does inside of em.

8a8mfh

iTrader: (3)

BTW this is not the first, second, third, or even fourth time I've seen and/or been a part of discussing how to drive a RMVB th400 in this forum. Maybe search and find more opinions.
Problem is there are too many opinions. Driving a RMVB th400 is not like piloting the space shuttle. Well unless you're going like 200 mph and you downshift to coast and the direct drum explodes through the floorboard. I have a pic of that somewhere believe it or not.

smokinHawk

iTrader: (48)

there was a good thread in the FI section of driving a RMVB and the reasons for it.
try a search in that section.