What is going on inside my TH400??

K

kidglok

Balls Deep
Joined
Oct 10, 2010
made a few passes today at the GM event at Englishtown. Drove home (thank god) everything was cool.
get home park it for a few hours, then decide to take it out to grab a coffee.
Well, on my way home i pull third gear and the car starts to slow down (like someone is stepping on the brakes)??? i roll to a complete stop, pull second then pull third, and if i feather the gas it drives normal, as soon as the rpms come up is like the invisible gremlin jumps on my brake pedal and the car tries nosing over to a dead stop. WTF??
 
kidglok said:
Would I have to pull the valve body to check?
Click to expand...

I would start by pulling the pan and checking the valve body bolts. If you see nothing wrong, then need to dig deeper by taking the valve body down. Look at the check balls and the seperator plate and make sure one didn't peen its way through.

Allan G.
 
turbobitt said:
I would start by pulling the pan and checking the valve body bolts. If you see nothing wrong, then need to dig deeper by taking the valve body down. Look at the check balls and the seperator plate and make sure one didn't peen its way through.

Allan G.
Click to expand...

thanks for your help allan,

its a rmvb hipster pro-tree transbrake, anything to look at there?
 
Check the sprag also?

Do you start your burn-out in first gear?

I am not a trany expert, but I have disabled my share of TH-400's, and have learned with a TH-400 NOT to start the burn-out in first gear, but second. :)
 
I forgot to add, do you have a trans brake? If so what I posted above is applicable.

Like Allan stated, low/reverse apply is what the trans brake does, and that could be somehow related to your issue?

And why with first gear burnouts, TH-400's do not like going into second at that RPM and load.
 
Nick Micale said:
I forgot to add, do you have a trans brake? If so what I posted above is applicable.

Like Allan stated, low/reverse apply is what the trans brake does, and that could be somehow related to your issue?

And why with first gear burnouts, TH-400's do not like going into second at that RPM and load.
Click to expand...

I do use a transbrake

I would start in first gear, I never did crazy burnouts I keep it under 40mph :)
 
kidglok said:
I do use a transbrake

I would start in first gear, I never did crazy burnouts I keep it under 40mph :)
Click to expand...

Does not matter, starting a burnout in first gear WILL damage the TH-400 as I am a poster boy for doing this. :(

When I changed my brakes from Wilwood to Baer, my front tires would then hold so I could start the burnout in second.

The trans does NOT like the 1-2 gear change in a burnout, talk to a TH-400 builder that has experience with a trans brake, and he will provide details why.

I do feel your pain, as I have paid the price a few times before I got "enlightened"! :oops:
 
kidglok said:
made a few passes today at the GM event at Englishtown. Drove home (thank god) everything was cool.
get home park it for a few hours, then decide to take it out to grab a coffee.
Well, on my way home i pull third gear and the car starts to slow down (like someone is stepping on the brakes)??? i roll to a complete stop, pull second then pull third, and if i feather the gas it drives normal, as soon as the rpms come up is like the invisible gremlin jumps on my brake pedal and the car tries nosing over to a dead stop. WTF??
Click to expand...
Sorry to be the bearer of bad news but..........
I can and will tell you what is wrong with your trans. The lugs in the case are broken that hold INT clutches in and second gear is applying against the direct drum. It is catosphraphic damage to the case and the trans. High line pressure can cause this as well as many other factors. However, your problem is going to require IMMEDIATE attention and DO NOT drive anymore. To prove my point, Drop pan and look for pieces of cast aluminum about 1/3 of an inch long. There will be a few of them in there.
I will bet the farm on this that it is your problem. Just drop pan and you will see. I know it cause I have seen it many times. Would be curious as to what you find.
But I know this is your problem.
You will need:
new direct drum (or reman yours if savable)
new INT pressure plate and possibly clutches
Case
A COMPLETE tear down and wash and reassemble.
Trans will be full of metal and converter, cooler and lines will need to be flushed.
This list is a good start.
Drop pan to confirm but I know what you are going to find. :(
(Only other thing I can think of if case is ok is shifter cable hanging hp and/or melted and not engaging fully but I doubt it. The prior broken case lug diagnois is going to be your issue.)
TEST ME....
Bruce
WE4
ptsxtreme@aol.com
 
WE4 said:
Sorry to be the bearer of bad news but..........
I can and will tell you what is wrong with your trans. The lugs in the case are broken that hold INT clutches in and second gear is applying against the direct drum. It is catosphraphic damage to the case and the trans. High line pressure can cause this as well as many other factors. However, your problem is going to require IMMEDIATE attention and DO NOT drive anymore. To prove my point, Drop pan and look for pieces of cast aluminum about 1/3 of an inch long. There will be a few of them in there.
I will bet the farm on this that it is your problem. Just drop pan and you will see. I know it cause I have seen it many times. Would be curious as to what you find.
But I know this is your problem.
You will need:
new direct drum (or reman yours if savable)
new INT pressure plate and possibly clutches
Case
A COMPLETE tear down and wash and reassemble.
Trans will be full of metal and converter, cooler and lines will need to be flushed.
This list is a good start.
Drop pan to confirm but I know what you are going to find. :(
(Only other thing I can think of if case is ok is shifter cable hanging hp and/or melted and not engaging fully but I doubt it. The prior broken case lug diagnois is going to be your issue.)
TEST ME....
Bruce
WE4
ptsxtreme@aol.com
Click to expand...


so basically i cant drive my car off a cliff, i'll have to push it
 
kidglok said:
so basically i cant drive my car off a cliff, i'll have to push it
Click to expand...
Pretty much..... .........................................at least you still got your sense of humor...LOL
The VB/Brake you have is great. I know Charlie and Hip personally and that is the ONLY 400 brake I will use. So good equipment, but drop the pan and tell me what you see.
The reason you don't want to do a burn out in low is the direct drum is spinning backwards at 2.48 times driveshaft speed and the direct clutch can explode or overrun the sprag. . Just like you NEVER neutral a 400 or any other trans for that matter, through the lights slowing down. Always let it come down to idle IN HIGH GEAR!
Good luck
Bruce
WE4
 
WE4 said:
Pretty much..... .........................................at least you still got your sense of humor...LOL
The VB/Brake you have is great. I know Charlie and Hip personally and that is the ONLY 400 brake I will use. So good equipment, but drop the pan and tell me what you see.
The reason you don't want to do a burn out in low is the direct drum is spinning backwards at 2.48 times driveshaft speed and the direct clutch can explode or overrun the sprag. . Just like you NEVER neutral a 400 or any other trans for that matter, through the lights slowing down. Always let it come down to idle IN HIGH GEAR!
Good luck
Bruce
WE4
Click to expand...

Your dead on with your diagnosis



image-1071260190.jpg
 
Sorry to hear about your misfortune KG.
This site is like going to a university. Priceless information. Thanks for the education. ;)
 
kidglok said:
Your dead on with your diagnosis



View attachment 163365
Click to expand...
HEHEHE.................. See old age and knowledge pay off again. Sorry you have to deal with this. First thing you do when you get a new trans in there is CK THE LINE PRESSURE! FLUSH EVERYTHING! CONVERTER ESPECIALLY! Throw the cooler out and start over. This is EXACTLY why I run a filter inline before the cooler! Good idea for the future.
Anyway, no sweat, the Bill is in the mail.......LOL You have to laugh because you don't want them to see you cry.o_O
Sorry to be the bearer of bad news......It is fun to be right sometimes but not at the expense of others.:(
Bruce
WE4
 
WE4 said:
HEHEHE.................. See old age and knowledge pay off again. Sorry you have to deal with this. First thing you do when you get a new trans in there is CK THE LINE PRESSURE! FLUSH EVERYTHING! CONVERTER ESPECIALLY! Throw the cooler out and start over. This is EXACTLY why I run a filter inline before the cooler! Good idea for the future.
Anyway, no sweat, the Bill is in the mail.......LOL You have to laugh because you don't want them to see you cry.o_O
Sorry to be the bearer of bad news......It is fun to be right sometimes but not at the expense of others.:(
Bruce
WE4
Click to expand...

lol its all good bruce, thanks for the info!! good thing my buddy had a th400 in his shed that i used as a case, and my buddy swapped everything over for me. I should be up and running by tomorrow afternoon :D
 
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