Ima get mines

iTrader: (3)

I've never owned a TH400. Is it okay to downshift into 2nd while cruising if you wana take somebody?

12secSS

iTrader: (30)

A stock or built one yes, I am not sure about some of the reverse manual valve body ones. What setup are you referring to?

Ima get mines

iTrader: (3)

It was already installed in the car but Its a mildly built up one from a 78 suburban I believe. It should be okay then.

jldak318

iTrader: (3)

im interested in the same question, but i have a th400 reverse manual valve body.

12secSS

iTrader: (30)

You should be OK.

You would have to find out if the trans builder set it up to allow downshifts at speed. This was discussed on a few threads a while ago, I don't recall the specifics. Since ours is a strictly race only Z28, it didn't apply to us. Do a search for TH400 downshifting and it should come up with some good results.

MeanWS6

i do it

skipperbisket

iTrader: (4)

with a reverse manual setup with a transbrake you shouldn't downshift it, it will eventually cause premature failure.... i think thats what caused my first th400 to kick it so quickly.

jv_Z28

iTrader: (1)

Yup, with a reverse manual set up you have to slow down, be at a low rpm to down shift or you can dry up the gear (stop the flow of trans fluid)

sleeperstyle

iTrader: (4)

so if you in 3rd cruizing at 60mph on the highway, you can't downshift to 2nd with little to no throttle and then once in 2nd gear nail it? i understand downshifting at signifigant rpms but with no engine braking i don't see how it would cause damage.

what if while you downshifted you kept into the gas just a little bit almost like a rev-match... dunno just asking. i've always wondered about this (downshifting a rmvb setup)

skipperbisket

iTrader: (4)

all i know is that i've heard from several reputable trans builders to not do it... so i wont be doing it on my new one

Zombie

iTrader: (2)

According to my builder Carl Rossler (goes for his transmissions, don't know about others) it's ok to downshift a RMVB TH400 as long as you are on the gas so the transmission does not free wheel. I downshift to first from a roll sometimes due to my 2.75 gears, but I'm always on the gas. My RMVB th400 was built so that 2nd gear does not freewheel like it normally does as well so I can do 3-2 without issue. I still make sure i'm on the gas though since it makes the transistion smooth.