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TH400 Transmission Builder Recommendations?

I rebuilt mine with a Jakes kit and learned a lot in the process of how everything works.
Whoever you get rebuild info from make sure it is for off road use. A lot of info and parts are not good for off road use. Jakes had an off road specific separator plate that replaced the normal street plate they sent out the first time. Drill diameters and checks mater. Mods matter. Tolerances and what gets loaded or unloaded changes with mods and parts so it is easy to screw things up.
Also make sure you use a case that has not been cross bread with different years of parts or by someone who didn’t know what they were doing.
 
HYDRODYNAMIC said:
I rebuilt mine with a Jakes kit and learned a lot in the process of how everything works.
Whoever you get rebuild info from make sure it is for off road use. A lot of info and parts are not good for off road use. Jakes had an off road specific separator plate that replaced the normal street plate they sent out the first time. Drill diameters and checks mater. Mods matter. Tolerances and what gets loaded or unloaded changes with mods and parts so it is easy to screw things up.
Also make sure you use a case that has not been cross bread with different years of parts or by someone who didn’t know what they were doing.
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Yeah...that's why I was staying away from shops that only listed drag race applications and nothing about offroad use.

I appreciate the tips.....
 
Sean said:
I'm not an auto guy....but is a trans brake something you'd want in a crawler?
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Want for a reason, no.

Is it cool to have for showing off in the same way that a useless triple low ratio is? Yeah.
 
white-rhino said:
Compression braking is a huge asset when down hill crawling.
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But engine braking isn't the same thing as a trans brake from what I gather in that you can buy manual valve bodies with engine braking (what I plan to do) and not get the trans brake.....or am I missing something?
 
Sean said:
But engine braking isn't the same thing as a trans brake from what I gather in that you can buy manual valve bodies with engine braking (what I plan to do) and not get the trans brake.....or am I missing something?
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Correct. Trans Brake usually engages Reverse with a switch/button and the forward gear with the shifter, locking movement.
 
RPS1030 said:
Correct. Trans Brake usually engages Reverse with a switch/button and the forward gear with the shifter, locking movement.
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Ah...thanks for the explanation. Yeah, can't see needing that on a rock buggy.
 
Sean said:
Ah...thanks for the explanation. Yeah, can't see needing that on a rock buggy.
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Even worse, the only drag car I've been around (so other valve bodies or things may have changed); it didn't shift to reverse to backup, it was shift to neutral and hold the button to engage the solenoid to backup. Would really be slow on a big climb turning into a rollover.
 
RPS1030 said:
Correct. Trans Brake usually engages Reverse with a switch/button and the forward gear with the shifter, locking movement.
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I misread the above. Yeah, I'm not talking about that and agree it's a waste. I'm referring to the difference between having compression braking and not having compression braking. IE: engine braking.
Sean said:
But engine braking isn't the same thing as a trans brake from what I gather in that you can buy manual valve bodies with engine braking (what I plan to do) and not get the trans brake.....or am I missing something?
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Yes. (again my bad above) I also found out the hard way that a non-engine braking valve body doesn't like power down shifting and is hard on the second gear cluster. (ask me how I know)
 
white-rhino said:
What did you replace it with?

I know this is a TH400 thread but I have a TH350. I see ATD does not make a TH350 valve body.
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My local trans guy is pretty secretive but I asked for a stock valve body with a shift kit. Might be this one:
transgo.com

TransGo | TH400 High Performance Valve Body Reprogramming Kit

Features: Automatic shift Street or full-race Holds 1st and 2nd to any RPM Back-shifts to 2nd and 1st at any RPM Tow&Go™, competition, pro-race, heavy
transgo.com transgo.com

Got tired of the cool guy race car trans and went back to a smoother setup.
 
white-rhino said:
I misread the above. Yeah, I'm not talking about that and agree it's a waste. I'm referring to the difference between having compression braking and not having compression braking. IE: engine braking.

Yes. (again my bad above) I also found out the hard way that a non-engine braking valve body doesn't like power down shifting and is hard on the second gear cluster. (ask me how I know)
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No worries, man. Just trying to soak in the knowledge here as I'm totally new to autos.
 
bunk said:
A comp guy runs one, 4cyl turbo rig fwiw
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So how's it used? I'm assuming you'd spin up the rpms at the bottom of a big, fairly smooth climb, then launch it when you hit the rpm you want/think you'll need?
 
Sean said:
So how's it used? I'm assuming you'd spin up the rpms at the bottom of a big, fairly smooth climb, then launch it when you hit the rpm you want/think you'll need?
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Yup. I imagine its quite a launch. cant remember his name but hes done a metric ton of hard trails.
 
white-rhino said:
Compression braking is a huge asset when down hill crawling.
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Compression braking with a RMVB in a T400 will kill it in short order.

Steve Culhane has built more off road T400's than anybody. If you are anywhere near SoCal, he is the guy to go to since Mogi retiered.
 
bdkw1 said:
Compression braking with a RMVB in a T400 will kill it in short order.

Steve Culhane has built more off road T400's than anybody. If you are anywhere near SoCal, he is the guy to go to since Mogi retiered.
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What does the RMVB do that is different than a standard valve body to make compression braking an issue?
 
HYDRODYNAMIC said:
What does the RMVB do that is different than a standard valve body to make compression braking an issue?
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I am not sure. I do know that it is death to the trans. A driver banging gears will kill a trans in 300 miles. One that shifts after braking will go 1000 miles without issue. If you need the specifics, call Steve. He explained it once to me but that was a long time ago.
 
Sean said:
So how's it used? I'm assuming you'd spin up the rpms at the bottom of a big, fairly smooth climb, then launch it when you hit the rpm you want/think you'll need?
Click to expand...

bunk said:
Yup. I imagine its quite a launch. cant remember his name but hes done a metric ton of hard trails.
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Justin Kielman had one in his old C4, in his old car. Would use it to spool the turbo and launch.
 
bdkw1 said:
I am not sure. I do know that it is death to the trans. A driver banging gears will kill a trans in 300 miles. One that shifts after braking will go 1000 miles without issue. If you need the specifics, call Steve. He explained it once to me but that was a long time ago.
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Tried to get clarification on not using compression braking on a TH400 from Steve via email. No response. I guess a call is in order.....
 
Sean said:
Tried to get clarification on not using compression braking on a TH400 from Steve via email. No response. I guess a call is in order.....
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Give Jake a call and ask him about it. He sells alot of rock crawler RMVB TH400's with engine braking and if they were that fragile I doubt he would sell them.
 
SLOWPOKE693 said:
Give Jake a call and ask him about it. He sells alot of rock crawler RMVB TH400's with engine braking and if they were that fragile I doubt he would sell them.
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Will do. Jake's and ATD are the top of my list at the moment.
 
06h3 said:
I refuse to use maximum off-road transmissions. I spoke to him at an event once and he said if he built me a 4L60E and if it got over 160* it will fail and he won’t honor the warranty….

160?! Really? They run hotter then that from the factory. He said a 4L80E can’t go over 180….

Then another trans builder who builds trans for racing opened up one of his transmissions and said he just throws billet everything at it but assembly on certain things left more to be desired.
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I have first hand experience with Maximum.
They have built transmissions that hold when other reputable builders have produced problems over and over.

I've also heard of issues with Jake's. At the end of the day, who you trust and the customer service are what matters.


As far as RMVB killing TH400s, it has to deal with the downshifting. Unless you're actively racing in the desert, a reverse VB is totally fine.
 
Bebop said:
I have first hand experience with Maximum.
They have built transmissions that hold when other reputable builders have produced problems over and over.

I've also heard of issues with Jake's. At the end of the day, who you trust and the customer service are what matters.


As far as RMVB killing TH400s, it has to deal with the downshifting. Unless you're actively racing in the desert, a reverse VB is totally fine.
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I'm considering going back to a standard VB with compression braking. The downshifting is brutal even for trail riding.
 
Engine braking is what makes the downshift brutal.
RMVB or FMVB won't change a thing.
 
white-rhino said:
I'm considering going back to a standard VB with compression braking. The downshifting is brutal even for trail riding.
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I'm coming from manual transmissions....I doubt I'll think it's brutal.
 
Bebop said:
Think about downshifting and dumping the clutch, every time.

The 2-1 shift will absolutely lock your tires, even at 10mph.

It's brutal.
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I clearly don't know what I don't know then. I guess I don't understand why the builder couldn't limit how high the RPMs would be able to climb as you downshifted.

Thanks for the info, regardless.

So I take it you don't recommend engine braking on a RMVB?
 
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