Th400 reverse manual hughes. Come in
Th400 reverse manual hughes. Come in So i'm putting a built th400 with a hughes reverse manual valve body in my truck and was reading where they say not to downshift from 3rd to 2nd under load or while vehicle is in motion.how big of a problem will this be if I do downshift under no load and at low speed? Any experience with this setup? Thanks.
I don't have a Hughes built TH400, and my car is a track only car, but it is a TH400 with RVMB. In the pits at the track if I get lugging along in 3rd I will take my foot off the throttle and put it in 2nd and then ease back in the gas, but at low speed.
I will shift 3rd to N when I'm coming up to the ticket booth, but I'm going less than 10mph that way I'm not starting out in the pits in 3rd.
I haven't had any issues operating mine that way.
Hope this helps.
I will shift 3rd to N when I'm coming up to the ticket booth, but I'm going less than 10mph that way I'm not starting out in the pits in 3rd.
I haven't had any issues operating mine that way.
Hope this helps.
TECH Junkie
Joined: Jul 2015
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So i'm putting a built th400 with a hughes reverse manual valve body in my truck and was reading where they say not to downshift from 3rd to 2nd under load or while vehicle is in motion.how big of a problem will this be if I do downshift under no load and at low speed? Any experience with this setup? Thanks.
You can go from 3rd to 2nd at freeway speed. What you don't want to do is let the car idle in 2nd after you downshift, then stand in it....you do that and you will probably knock the lugs out of the case. Keep a light load on it as you downshift and you will be fine. And you can downshift at no load as you come to a stoplight with no issues.
TECH Junkie
Joined: Jul 2015
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I can't remember where I seen it, but I was reading a thread about a guy that kept killing cases. At the time, he didn't really understand how transmissions operated...especially with a brake/mvb involved. When asked how he was driving the car... he revealed that he was running up against the sprag (not how he worded it, but it's essentially what he was doing). Not sure why the sprag was living but killing the case.... but that's the only reason I mentioned the case lugs.
Not going to affect the case lugs because the intermediates are already applied in 2nd or 3rd.
Case lugs get blown out when you have excessive line pressure, install the wrong snap ring, etc. I make a support to prevent blowing them out on stock cases. Aftermarket cases like Reid already have additional splines to prevent it.
On a 3-2 downshift, you're just releasing the direct clutches. You don't want to do it at high speed because the drum can explode.
You're correct on what not to do. When you hit it from idle, the sprag goes from overrunning to locked. It can roll the sprag.
Case lugs get blown out when you have excessive line pressure, install the wrong snap ring, etc. I make a support to prevent blowing them out on stock cases. Aftermarket cases like Reid already have additional splines to prevent it.
On a 3-2 downshift, you're just releasing the direct clutches. You don't want to do it at high speed because the drum can explode.
You're correct on what not to do. When you hit it from idle, the sprag goes from overrunning to locked. It can roll the sprag.
11 Second Club
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I've been OK so far downshifting my turbo action rmvb T400 from 3rd to 2nd at sensible lower rpms on the highway, then going WOT. Always have some light throttle in it while downshifting, as you don't want to overrun the sprag.
Any other time you hit the throttle in 1st gear or 2nd gear, ALWAYS upshift to 2nd and then 3rd under power. Never back off the throttle before you've shifted it into 3rd with a rmvb t400, regardless of speed or rpm or amount of throttle.
Any other time you hit the throttle in 1st gear or 2nd gear, ALWAYS upshift to 2nd and then 3rd under power. Never back off the throttle before you've shifted it into 3rd with a rmvb t400, regardless of speed or rpm or amount of throttle.
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TECH Junkie
Joined: Jul 2015
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And even though this wasn't asked, I feel it's important. Whatever you do, do NOT for any reason throw it into neutral while going through the traps....or after a long pull on the freeway. Doing that turns your transmission into what's essentially the equivalent of a pipebomb..
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