Filling a new TH400 transmission with fluid

[bkahler]

Our Argosy Motorhome has a new Turbo 400 transmission that has yet to have any fluid poured into it. What is the procedure for filling a new transmission prior to first using it?

Do you just pour the recommended amount of fluid into it and call it good or do you pour X amount in, start the engine and then monitor and fill until the dipstick reads right?

Oh yeah, I'm assuming Dexron III is the correct fluid to use?

Thanks!

Brad

[osolow]

did you install the transmission?
if so did you remember to fill the torque converter with fluid?
if so i would pour in some fluid and start it up and check your fluid level
and add until your at the correct level
i would also suggest getting a tranny pan that has a drain plug in it for easier service
and that holds a couple extra quarts.
just don't forget to recheck it after your first short trip.

[ronstory]

Yes... you need to make sure that the torque converter was filled with fluid. Assuming a stock tranny pan, I normally drop a quart in the TC and then 6 quarts in the tranny... and start it up and leave it in park and then check the fuild after a minute of running and add what is needed. Do *not* try and drive the vehicle until the fluid level is correct. Take you time and you will happy.

Also, don't forget to adjust the kickdown.

[Guido]

Dexron III is the right fluid.
I forget how much a 400 should hold, but put about half that amount in, start the engine, shut it off, check if there is any showing on the dipstick. if so, restart and add until the fluid is at the lower fill level (add). Put it in all gears, and recheck. Fill again to "add", and let it finish warming up. The fluid will expand a lot when it gets hot, so check the level again after it is warmed up all the way.
Drive around the block a couple of times, and finish filling to "full" mark. Even though you can find approximate capacities, they are only approximate. depth of transmission pan, length of cooling lines, size of transmission cooler(s) all effect capacity.

[bkahler]

Wow, great information!

Here is what has transpired with this transmission to date. We bought the motorhome and it was advertised as having a freshly rebuilt 350 and freshly rebuilt TH400. The engine had been test run before installation but I don't know anything about what was done with the transmission after its rebuild.

We opted to pull the 350 and put in a 454 that we've rebuilt for towing purposes. The 350 was as advertised in that it was newly rebuilt so I would assume the same for the transmission.

Fortunately the engine is not installed and the torque converter is accessible. I will pull the torque converter and check to see if any fluid is in it and proceed from there.

I have what is supposed to be a deeper pan for the 400, I'll check about installing that as well.

Guido, my engine start up requirements are to start the engine and keep the RPMs at around 1700 to 1900 for the about 15 to 20 minutes. This is to ensure the cam and lifters are bedded properly. I'll probably have to fill the transmission closer to the factory recommended fill level for the first start up. The engine will be started several more times before it ever gets taken off the jack stands so hopefully I can ensure the transmission is filled properly before that time.

Something I forgot to ask about was transmission coolers. I don't plan on using the original transmission cooler that was mounted in front of the radiator as I don't know the history of its prior use. What I would like to do is add an external cooler somewhere under the frame of the Motorhome with a fan for cooling purposes. I will still use the transmission cooler part of the radiator. Which brings up another question. When installing a remote cooler should the line run from the transmission to the radiator then to the external cooler and then back to the transmission. Or should it be just the opposite? I would think the latter which would send slightly cooler oil through the radiator which I would think would help in engine cooling.

Thanks!

Brad

[osolow]

you could run a tranny cooler cleaner throw the original cooler and then use it as long as it doesn't leak.
any parts store will carry it i think its called Clean flush and its in a large looking shaveing cream can, the label is green and silver.

If you do decide to run an aftermarket cooler and fan i would just run it throw the cooler and wouldnt run it throw the radiator. it's really not going to cool the tranny fluid enough to reduce or change the engine temp.

on running the engine for break in just add some extra tranny fluid and check it while it's running and add if needed just don't add to the full mark on the dip stick fill it to right below to allow for fluid expansion and when you let the engine idle down.

when you remove the TQ converter and reinstall it make sure you get it in correctly and it cogged in to the pump correctly.

[ROBERT CROSS]

Hope it's not too late...

The transmission lines and cooler should be cleaned and flushed while the transmission's out.

IMHO...Do a transmission power flush and fill after 1500mi.

[bkahler]

you could run a tranny cooler cleaner throw the original cooler and then use it as long as it doesn't leak.
any parts store will carry it i think its called Clean flush and its in a large looking shaveing cream can, the label is green and silver.

I really don't want to use the old cooler. Its 35 years old and I know what shape I was in at age 35 and I can't imagine the cooler being any better!

If you do decide to run an aftermarket cooler and fan i would just run it throw the cooler and wouldnt run it throw the radiator. it's really not going to cool the tranny fluid enough to reduce or change the engine temp.

on running the engine for break in just add some extra tranny fluid and check it while it's running and add if needed just don't add to the full mark on the dip stick fill it to right below to allow for fluid expansion and when you let the engine idle down.

when you remove the TQ converter and reinstall it make sure you get it in correctly and it cogged in to the pump correctly.

Sounds good.

Hope it's not too late...

The transmission lines and cooler should be cleaned and flushed while the transmission's out.

IMHO...Do a transmission power flush and fill after 1500mi.

No, not to late!

As a matter of fact one of the steel lines from the transmission to the radiator has been plugged by a dirt dauber nest. I'm going to pull both lines and use a pressure washer to clean them out.

Thanks,

Brad

[TomW]

Originally Posted by bkahler

... Oh yeah, I'm assuming Dexron III is the correct fluid to use?

Actually, they're up to DEXRON-VI now.

Originally Posted by Castrol label

Premium synthetic blend formula exceeds DEXRON-III H requirements ... Certified and approved by General Motors for all cars and trucks that require DEXRON, DEXRON-III H, III, IIE, and II.

I doubt you will find anything at the store except this latest formulation.

Tom

[bkahler]

Originally Posted by TomW

Actually, they're up to DEXRON-VI now.

I doubt you will find anything at the store except this latest formulation.

Tom

Shows you just how often I buy automatic transmission fluid!

[GlenCoombe]

Interesting comments but so far no one has mentioned synthetic for the tranny.

It's my info that synth. fluid works well especially for towing due to lower temps being generated.

I could be all wrong but for a new setup I'd be exploring it.

[osolow]

you could go ether way on the fluid type
just keep it serviced and you'll be fine with non synthetic and its a bit cheaper.

just be mindful of the temp your tranny gets and don't be really hard on it IE burnouts neutral drops and running around in first gear at 70mph

[bkahler]

Glen,

Good point about the synthetic oil. On new engines you don't use synthetic during break-in but I can't image that should be a problem with an automaticc transmission. After all the reason for using dino oil in a new engine is to promote cylinder and ring wear to allow the rings to seat. I don't know of anything inside an automatic that you would want to wear like that!

Thanks,

Brad

[Airslide]

Originally Posted by bkahler

Glen,

Good point about the synthetic oil. On new engines you don't use synthetic during break-in but I can't image that should be a problem with an automaticc transmission. After all the reason for using dino oil in a new engine is to promote cylinder and ring wear to allow the rings to seat. I don't know of anything inside an automatic that you would want to wear like that!

Thanks,

Brad

I personally agree on this point but interestinly the manufactures that we work with Mercedes Benz and Volvo use factory fill Mobil 1 (Full syntetic) and Castrol syntec. Todays engines are broken in with synthetic.
I still wouldnt do it because im old school but technology has changed so much these days..

Vin

[bkahler]

Originally Posted by osolow

you could go ether way on the fluid type
just keep it serviced and you'll be fine with non synthetic and its a bit cheaper.

just be mindful of the temp your tranny gets and don't be really hard on it IE burnouts neutral drops and running around in first gear at 70mph

HA! No burnouts for this motorhome. We're spending way to much money and time on it to treat it like that.

The only thing that worries me is having the transmission fail or the cruise control unit fails while driving on the highway. I've had it happen once when pulling a trailer in our old 81 Chevy 1-ton dually pickup. Scared the crap out of me when it happened. I caught it fast enough that there was no damage to the engine and I think I was just plain lucky in that regard.

Brad

[bkahler]

Originally Posted by vlamica

I personally agree on this point but interestinly the manufactures that we work with Mercedes Benz and Volvo use factory fill Mobil 1 (Full syntetic) and Castrol syntec. Todays engines are broken in with synthetic.
I still wouldnt do it because im old school but technology has changed so much these days..

Vin

Vin, for me the newest engine I've had the pleasure of rebuilding is from the mid 70s which I consider old school.

I can't even imagine what the metals and and machining processes are like for these new fangled engines they're using in todays vehicles. On the older engines if you try and break them in with synthetic you're never going seat the rings.

Personally I like the older stuff, I can understand it..... .

Brad

[ROBERT CROSS]

New engine break in??...start drive 5mi, your done. Things do change.

All GM SS models come from the factory with Mobil 1. Differentials w/GM synthetic gear lube.

Put the synth. of your choice in the tranny and drive away.