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TH400 Transmission Builder Recommendations?

A really loose converter will alleviate it some but it’s still pretty violent compared to any “normal” vehicle.
 
I like my RVMB with engine braking. Yes, 2-1 downshift can be violent if you are going too fast. Either you need to get to first and live with the bang, or learn to shift as you get close to a stop.

Most of my early wheeling was done with a manual trans, so I like throwing it in a gear and engine braking down a hill. So I deal with the side effects.
 
Sean said:
I clearly don't know what I don't know then.
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No worries, we're all learning.

Sean said:
I guess I don't understand why the builder couldn't limit how high the RPMs would be able to climb as you downshifted.
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It's a "dumb" hydraulic trans that has been simplified again. No brains, it just does what you tell it to do.
If you had a 4L80 or a 6L80 with a TCM, then you could force it to do more complex stuff, like prevent downshift at certain conditions etc

Sean said:
So I take it you don't recommend engine braking on a RMVB?
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I love mine. Suits my use (trail riding) well. I just wait to be almost at a stop to re-engage first gear when I don't want the jerking.
I just want you to make sure you understand what you're jumping into.

PS: IDK why we're talking about RMVB here. Engine braking is the culprit. Not the pattern.

JohnnyJ said:
I like my RVMB with engine braking. Yes, 2-1 downshift can be violent if you are going too fast. Either you need to get to first and live with the bang, or learn to shift as you get close to a stop.

Most of my early wheeling was done with a manual trans, so I like throwing it in a gear and engine braking down a hill. So I deal with the side effects.
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I agree 100%
 
So I take it a stock auto trans from the GM factory does not have engine braking? I know my more or less stock 4l60 in my toyota does compression brake in some gears(I don't think 1st is one of them). Is it just not as severe compression braking, or a more complex trans that limits the severity of the compression braking vs the dumb trans that is all in 100% of the time? I have only driven manual trans and stock auto trans off road. Nothing performance wise.
 
I'll always have a rmvb(and modded gates for a fast 1st to r shift) with engine braking and a stall convertor. Im also going to do a block plate so it wont go into park on my next shifter.

This is the first discussion ive read about the 2-1 shift. I did it ONCE and knew it was bad bad bad and never did it again. Its very gnarly and if you know anything about mechanics you know its not a smart thing to do.
 
Bebop said:
No worries, we're all learning.


It's a "dumb" hydraulic trans that has been simplified again. No brains, it just does what you tell it to do.
If you had a 4L80 or a 6L80 with a TCM, then you could force it to do more complex stuff, like prevent downshift at certain conditions etc


I love mine. Suits my use (trail riding) well. I just wait to be almost at a stop to re-engage first gear when I don't want the jerking.
I just want you to make sure you understand what you're jumping into.

PS: IDK why we're talking about RMVB here. Engine braking is the culprit. Not the pattern.


I agree 100%
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I only mention RMVB b/c that's definitely what I'm getting on the TH400s.

From reading your build thread....I think you're still running a TH400 too, right?

I'm inclined to think I'll find it useful to have engine braking.
 
bunk said:
I'll always have a rmvb(and modded gates for a fast 1st to r shift) with engine braking and a stall convertor. Im also going to do a block plate so it wont go into park on my next shifter.

This is the first discussion ive read about the 2-1 shift. I did it ONCE and knew it was bad bad bad and never did it again. Its very gnarly and if you know anything about mechanics you know its not a smart thing to do.
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So as uneducated as I am, it sounds like if you're going to downshift from 2-1, you need to be going VERY slow.....which is fine. I see myself using it much more in 3rd or 2nd gear anyway....

Stupid question but, am I correct that engine braking in this context would act like a manual trans you just left in a certain gear on say a long downhill where you didn't want to really use the brakes much....just let the compression braking from the engine slow you down? That's all I can see me really using the feature for. If I need to slow markedly, I'm going to use the brakes.
 
Sean said:
So as uneducated as I am, it sounds like if you're going to downshift from 2-1, you need to be going VERY slow.....which is fine. I see myself using it much more in 3rd or 2nd gear anyway....

Stupid question but, am I correct that engine braking in this context would act like a manual trans you just left in a certain gear on say a long downhill where you didn't want to really use the brakes much....just let the compression braking from the engine slow you down? That's all I can see me really using the feature for. If I need to slow markedly, I'm going to use the brakes.
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Leaving it in second down a hill for braking is fine. Coming into a corner and dropping to first to get the rear to step out rally style is not. Get your braking done and when you're ready to throttle out, down shift and stand on it.
 
Sean said:
So as uneducated as I am, it sounds like if you're going to downshift from 2-1, you need to be going VERY slow.....which is fine. I see myself using it much more in 3rd or 2nd gear anyway....

Stupid question but, am I correct that engine braking in this context would act like a manual trans you just left in a certain gear on say a long downhill where you didn't want to really use the brakes much....just let the compression braking from the engine slow you down? That's all I can see me really using the feature for. If I need to slow markedly, I'm going to use the brakes.
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After that one time i did it, i always came to a complete stop before hitting first. You gotta realize its full manual, you become the brain of the trans. There is zero cushion, its just BAM! 1st gear.
 
Bebop said:
Engine braking is what makes the downshift brutal.
RMVB or FMVB won't change a thing.
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I didn't say FMVB. I said standard VB, as in automatic shifting. I had that on my previous rig and was much more satisfied with it. Go from R to D and it starts in 1st. The only downside is you can't start in 2nd or 3rd, which I never do anyway. I eliminated the auto kick down and downshifted manually.
 
JohnnyJ said:
I like my RVMB with engine braking. Yes, 2-1 downshift can be violent if you are going too fast. Either you need to get to first and live with the bang, or learn to shift as you get close to a stop.

Most of my early wheeling was done with a manual trans, so I like throwing it in a gear and engine braking down a hill. So I deal with the side effects.
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I just don't like the bang. It's hard on stuff and I seem to struggle keeping transmissions together. I don't see any downside to going back to what was in my YJ.
 
To add to the brain cooking discussion here - I have a RMVB with compression braking in 2nd and 3rd, but not 1st. It's a cheetah for a 904, and I like it. I switched from a RMVB with compression braking in all gears and actually prefer not having it in first.

RMVB because i like that 1st and R are right next to each other for those slam reverse to save a roll over backwards.
I do have a gate in my shifter to prevent Hitting park.
 
Opiebennett said:
To add to the brain cooking discussion here - I have a RMVB with compression braking in 2nd and 3rd, but not 1st. It's a cheetah for a 904, and I like it. I switched from a RMVB with compression braking in all gears and actually prefer not having it in first.

RMVB because i like that 1st and R are right next to each other for those slam reverse to save a roll over backwards.
I do have a gate in my shifter to prevent Hitting park.
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And that's another point too....I was originally looking at the RMVB from TCI that only had compression braking in 2nd and 3rd. Seems like that might be a good compromise....just not sure how common that is among ATD's, Jake's, Maximum's, etc. TH400 builds.
 
Sean said:
From reading your build thread....I think you're still running a TH400 too, right?

I'm inclined to think I'll find it useful to have engine braking.
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Yep. Still running it. Still liking it.
You just have to make due with the shortcomings.

Sean said:
So as uneducated as I am, it sounds like if you're going to downshift from 2-1, you need to be going VERY slow.....which is fine. I see myself using it much more in 3rd or 2nd gear anyway....

Stupid question but, am I correct that engine braking in this context would act like a manual trans you just left in a certain gear on say a long downhill where you didn't want to really use the brakes much....just let the compression braking from the engine slow you down? That's all I can see me really using the feature for. If I need to slow markedly, I'm going to use the brakes.
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You’re correct.

white-rhino said:
I didn't say FMVB. I said standard VB, as in automatic shifting. I had that on my previous rig and was much more satisfied with it. Go from R to D and it starts in 1st. The only downside is you can't start in 2nd or 3rd, which I never do anyway. I eliminated the auto kick down and downshifted manually.
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Understood
 
Sean said:
And that's another point too....I was originally looking at the RMVB from TCI that only had compression braking in 2nd and 3rd. Seems like that might be a good compromise....just not sure how common that is among ATD's, Jake's, Maximum's, etc. TH400 builds.
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I tried that once. Not a fan.
In the end, the only gear I like it in is 1st for long downhills so I don't have to sit on the brakes all the time. My trans does a really good job at that.
 
Bebop said:
I tried that once. Not a fan.
In the end, the only gear I like it in is 1st for long downhills so I don't have to sit on the brakes all the time. My trans does a really good job at that.
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I'm going to have so many gearing options with the 3 speed tcase (2.5 and 5.44 low ranges) that I'm not sure it will matter.
 
Sean said:
I'm going to have so many gearing options with the 3 speed tcase (2.5 and 5.44 low ranges) that I'm not sure it will matter.
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Oh yeah, with a 5.44 low range, even 3rd will be fine :laughing:
 
engine braking valve bodies are murder on internals. probably an unpopular opinion but they are a fad that developed when everyone started switching from manuals to autos and wanted them to drive the same. when you downshift on coast then apply throttle it basically slingshots the internals from one shock load direction to another. there was a thread on the old board as it was dying that went into detail why these valve bodies are a terrible idea. i wish i had saved it.
 
cdemart2 said:
engine braking valve bodies are murder on internals. probably an unpopular opinion but they are a fad that developed when everyone started switching from manuals to autos and wanted them to drive the same. when you downshift on coast then apply throttle it basically slingshots the internals from one shock load direction to another. there was a thread on the old board as it was dying that went into detail why these valve bodies are a terrible idea. i wish i had saved it.
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So is demand so high for the feature that the builders just give the customers what they want?
 
cdemart2 said:
engine braking valve bodies are murder on internals. probably an unpopular opinion but they are a fad that developed when everyone started switching from manuals to autos and wanted them to drive the same. when you downshift on coast then apply throttle it basically slingshots the internals from one shock load direction to another. there was a thread on the old board as it was dying that went into detail why these valve bodies are a terrible idea. i wish i had saved it.
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I mean... every single one of my friends drives with an engine braking manual VB.
Usually transmissions will last 5+ years.

If it was that bad they would have broke a long time ago.
 
Bebop said:
I mean... every single one of my friends drives with an engine braking manual VB.
Usually transmissions will last 5+ years.

If it was that bad they would have broke a long time ago.
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But to be fair, you and your group are pretty easy on stuff. Cheater lines, stackin rocks, winchfest, that sorta thing. Some of us acktually wheel.....
 
Wisconsinite said:
But to be fair, you and your group are pretty easy on stuff. Cheater lines, stackin rocks, winchfest, that sorta thing. Some of us acktually wheel.....
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i even remember this one time where he uses his rim to move rocks with something unknown to me, torque..... i think thats whats it called....
 
chaplinfj60 said:
ohh i know he smashed a rock and tested out his knuckle welds quite few month back,..
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and tore a whole truss off a 14b. Dude wheels.

Meanwhile, I've had a RMVB with engine braking in my rig for going on 4 years...... Never had an ounce of problems. It also hasn't left it's stand......
 
what i love about this thread is i am learning about autos.... even ones on the bench. i did a complete factory tranny right down to the stall. my thought process was stay simple. and in a round about way have tcase gears and axle gears it should be easy for a tranny to not feel the load. i dont know just how i was thinking.
 
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