Technical TH 400 not going in gear

I got a TH 400 from a running and driving vehicle. Its been mated to a 283 SBC. I did what most guys would do while it was out. I flushed the fluid, new seals, new filter, new transmission mount, new gasket, and new modulator. I installed a new B&M shifter.

Everything seems to line up on the shifter. I have about 21" of vacuum at the carburetor, to the transmission modulator. It has an external trans cooler, and the fluid level checks out ok. This was a manual transmission truck and doesn't have the connector to the manifold like I've noticed on other auto trans chevys. I checked if the modulator leaked, and it doesn't.

It doesn't go into any gear. I mean nothing. I don't even feel the little jerk you feel when a gear goes in.
Thank you in advance.

Art.

 

You do have the converter bolted to the flywheel, don't you?

 

Is the converter engaged into the front pump? Un bolt it from the flex plate and spin it while pushing back and see if it clunks into place. If it does, you are not spaced back from the flex plate correctly.

 

The converter is bolted to the flywheel.

@BJR, I had it not all the way into place. There was a space of about 3/4" between the bell housing, and the block. So, I don't think that is the case. Is there a way to check that without dropping the drive shaft and dismantling everything.

 

OK< back up here a step, is there still a gap or did you get the gap closed up and did you happen to have to force things to get it to close up.
The converter should have clunked into place in the pump when you turned it by hand and put a little pressure on it by hand before you put the trans in. Usually when you have it all the way in the pump and get the trans bolted to the block right you can pretty well slide your fingers up between the flex plate and converter before you slide the converter forward to bolt it to the flexplate. If it wasn't all the way in the pump and you forced the trans up to the block by tightening the bolts there is a pretty good chance you broke the dogs in the pump that engage the converter. You did get the trans up square against the block before you fired it up?

 

Mr48chev, there was no gap. In fact, I couldn't get the bolts to reach the threads, until I pulled the trans out, pushed (clunked) the converter it into place, and then, it ****ed right up to the block. I don't remember if there was a space between the converter and the flex plate.

If I remove the bolts that fasten the converter, to the flex plate, would I have that space you're talking about?
I'm ***uming the "dogs" you're talking about, are the tabs that lock in to the converter. Is there a way to check if those are broken?

 

Disconnect the converter from the flex. Push back on the converter. It should slide back about an eighth..give or take.. Just make sure it pushes back.
Disconnect both cooler lines at the trans..Spin the converter around in the direction of rotation by hand..
Report back..

 

markyac, I'll get back to you tomorrow. Is there something I should look for?

 

See if it pumps any fluid out. It should pump a little bit anyway.
If you don't see any, bolt the converter back up and the lines.
Loosen one of the lines at the cooler just a little and start it up for about 3 seconds...See if it pumps fluid.
It not ..Get the tools out..You may have damaged the front pump.

 

Maybe the linkage under the pan came off?

 

The connector to the manifold? You mean like a TV cable or a kick down connected to the carb, right? Turbo 400s kick down electrically, there will be a switch either under you gas peddle that looks like a dimmer switch or a switch on the carb. That won't make it not go into gear but just to clear that up.

Now for questions and suggestions, if I hit something that someone else already said then check that one twice.

Start with the easy, unhook the linkage and manually put the transmission in park the parking pawl is mechanical so you can tell if it is in park because you won't be able to turn the tail shaft (or drive shaft either.) Now with your shifter linkage in the park position hook the cable up you shouldn't have to move the shift dog to do that, so if it doesn't just fall into place adjust your shifter.

That was easy and while you were under there you did confirm that the dog was properly installed correct?

Now lets think about what you have done to the ****** itself, you changed the oil, are you sure that the filter has not fallen off the pickup tube? if so it will probably not pick up fluid. it has to pick up fluid to go into gear. Did you dump the fluid out of the converter? if so did you replace it prior to ***embly? A dry converter will make one problematic.

While you were in there did you manage to knock the shaft loose from the valve body? that will make one not go into gear.

How much fluid did you put in it? it is probably not full, you have to run it through the gears, then check the fluid again while it is running, then add fluid and do it again and keep doing that until it shows full or nearly full on the dip stick.

Done all that? well let me tell something on me. Once I installed an automatic in an old chebby, I fire it up and through it in gear and nothing. damn it got a bad one. So I jacked it up and got ready to roll under there and noticed a puddle under the tail shaft and looked up to where the drive shaft was supposed to be, supposed being the operative word here. Duh'Oh

it is probably something simple that you overlooked. double check everything and call us when you have found the problem.

 

The dogs are machined tabs in the center of the pump drive gear. They are cast iron. They are part of the gear.

If the convertor was not engaged into these, and you pulled the transmission in with the bolts, they most likely broke off. The converter "goes in" more than just one "clunk", it goes a bit more as the dogs get lined up.

If you recall that there are two notches at the outer part of the convertor hub that goes into the trans? Those notches are what the pump dogs lock into.

The only way to see these, is by pulling the trans out, pull the convertor out, and look inside the pump. You are looking for two metal "squares" that are 180 degrees apart.

 

Have you ever seen this happen? What specifically was the problem?

 

markyac, I disconnected the line to the cooler and spun the converter. I had some fluid leak out initially, and then nothing when spinning the converter.

models916, I'm almost sure the linkage underneath is not off. When its in Park, the shaft and wheels don't spin, when its out of Park, everything turns and spins. It's just when it ON, that it doesn't go into gear.

Porkn******, by connector, I meant fitting for vacuum. This is a '63 C20, there's nothing under the pedal, other than sheet metal. If you're right, that means the switch on the trans is not the reverse switch like I thought.
The shifter IS installed correctly. I cant see how the filter would fall off if it has a bolt to hold it.
I did dump the fluid from the converter and I did replace it.
Honestly, I have no idea what you mean by "knock the shaft loose from the valve body".
I don't know how much fluid I put back in. I know one gallon was full and the other wasn't. I will check that thoroughly tomorrow.

When I tested the front pump, like markyac said, I heard a noise as if the converter was not filled all the way. I'm starting to think it's just a low fluid issue. My fingers are definitely crossed.

F&J, we ARE talking about the same thing.

 

Ok, fellas.
After going through the gears, checking fluid, adding fluid, and repeating the process several times, until it kept getting higher and higher on the dipstick, it got rolling. I even drove it up the street and back. But it seams as if the gears are a little long, compared to the C6 in my Ford.

Is there a way to adjust that, or is that how those ******s run? It almost feels like when you ride the clutch on a stick shift.

I know there's a difference in Ford and Chevy stuff. I didn't expect them to run the same.

 

The gear ratios are almost the same in a C6.
Are you saying it takes too long to shift at normal throttle?
You can pick up a governor kit at fool with that..Not hard at all on a 400.

 

Governor? Is that the modulator?

 

Uh maybe it is a little harder than I previously thought.
It's under the 4 bolt cover behind the oil pan on the right side.
Go on Youtube and look it up .Lots of info there.

 

How high on the dip stick are you?
I'd start suspecting the filter pick up tube.

 

Just worked on a truck here that the guy said he had to add fluid till it was halfway up the stick till his truck moved...pulled the pan and the filter had fallen off, tube was part of the filter so it wasnt getting fluid. If you have been adding more than normal fluid that would make sense....

****, posted and noticed 31 beat me to it...

 

If your governor is bad the trans will not shift. I suspect the o-ring on the filter or adapter is leaking. An over filled trans is as bad as running one low on fluid.

 

Yes. True .
Do you guys read through the whole thread before commenting?
The OP said he got the thing moving around but it took a bit too long to shift.
The governor comment was in response to this.

 

I read a bit too much fluid too

adding fluid, and repeating the process several times, until it kept getting higher and higher on the dipstick, it got rolling

 

Bro, I'm like you .I like to use my own experience to help these guys.
This is hard enough over the internet..even with all the pertinent facts, which we rarely get.
For instance ..Did you keep adding fluid with the engine running until it read way over full?
Is that the only way the thing would drive around?
Or was it just low after the converter filled up?

Then yes, I would yes the filter may not be picking up the oil.
But who knows, without more details

 

[QUOTE="
. But it seams as if the gears are a little long, compared to the C6 in my Ford.

Is there a way to adjust that, or is that how those ******s run? It almost feels like when you ride the clutch on a stick shift.

I know there's a difference in Ford and Chevy stuff. I didn't expect them to run the same.[/QUOTE]

Do you mean long time between shifts or acts like it's slipping? Shift interval sounds like governor, slipping could be converter. Is it the converter that came with the ******? Any idea what it's stall speed is?

 

FTR, the oil on the dip stick looked fine except after I went through the gears. Then, I would add accordingly. Transmission fluid is right where it should be.

 

My favorite is when the details change

 

Ok. Lets get it all straight.

In my F100, when I step on the gas, it F#@&ING GOES. I feel the transmission going through the gears. This chevy 400, does NOT do that. I can't even tell how many gears it goes through by the time I have to turn around at the end of my street. I know it shifts, cause it not at high rpms when I have to slow down at the end of the street.

That's what I mean when I say "like when you ride the clutch".

When it comes to the trans fluid....

I filled the converter before installing it. It has an external oil cooler. I put a litte more than a gallon of fluid. On the dipstick, it was within the low, and high marker. That is when it wasn't going into gear. Every time I shifted through all the gears and checked the fluid level, I had to add more because it was below the mark on the dipstick. Eventually, I got it to the FULL mark on the dipstick.

I didn't know a th400 takes 6qt of trans fluid. Plus the oil cooler, and the 6ft of oil line.

 

Takes about 10-11 on a dry build, deep pan.
Can you hold each gear and make it like you want, manually?

 

Maybe it's a Dynaflow and not a 400.