Transmission Dyno

biggy238

biggy238

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Aug 3, 2008
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With the trans (builder) wars alive and well, I think it might be time to air out this question.

Why does no-one provide a dyno sheet with their transmissions? If they do, who is it?

What equipment is needed to do this and what is standard practice for those that do possess them?

Many users here are well versed on chassis and engine dynamo meters. There is no reason the same can't be done for an auto transmission IMO

Monkey Fist Rage
 
Because trans dynos start at 80k without tooling or software.
 
There's one at Wyotech. We had to run our Allison trans on it after we rebuilt them. The dyno made enough power that you could lock up the converter, load it down and get them to chatter.
 
Goerend has 2 i think. Even has a valve body "Dyno" to check out valvebodies out of transmissions.
 
I dyno check my tranny every pass down the 1/4 mile strip. When it fails, I know I overloaded it too many times, replace the failed or worn parts, make upgrades where necessary, and then dyno it again another 300 times until it fails.

I honestly think a stock Dodge 48re tranny would hold 500-600 HP on a tranny dyno for a short run or two, even with a chattering single disk converter. Unless you do a long-term test, all you are really doing is briefly verifying build quality control, and tuning shift points. Long term reliability has too many factors to simulate on a dyno.
 
Big Blue24 said:
I dyno check my tranny every pass down the 1/4 mile strip. When it fails, I know I overloaded it too many times, replace the failed or worn parts, make upgrades where necessary, and then dyno it again another 300 times until it fails.

I honestly think a stock Dodge 48re tranny would hold 500-600 HP on a tranny dyno for a short run or two, even with a chattering single disk converter. Unless you do a long-term test, all you are really doing is briefly verifying build quality control, and tuning shift points. Long term reliability has too many factors to simulate on a dyno.
Click to expand...

What was the SRT10 engine rated at?

It would hold up to over 2000 passes, a pass consisted of full throttle until about 75 mph, then half throttle to 90 ish(IIRC). The drag behind it simulated an 8 foot tall trailer pulling into a 20 MPH headwind. For comparison a 47RE never made it past 1700.
 
Big Blue24 said:
I dyno check my tranny every pass down the 1/4 mile strip. When it fails, I know I overloaded it too many times, replace the failed or worn parts, make upgrades where necessary, and then dyno it again another 300 times until it fails.

I honestly think a stock Dodge 48re tranny would hold 500-600 HP on a tranny dyno for a short run or two, even with a chattering single disk converter. Unless you do a long-term test, all you are really doing is briefly verifying build quality control, and tuning shift points. Long term reliability has too many factors to simulate on a dyno.
Click to expand...

So you're removing shock loading from the ability of the dyno?

Monkey Fist Rage
 
biggy238 said:
So you're removing shock loading from the ability of the dyno?

Monkey Fist Rage
Click to expand...

It took me too long to edit.

So you're removing shock loading from the ability of the dyno as a testing procedure?

I'm also only partially into the "too many variables"
Give me some examples please.

The only one that comes to mind for me is the ability for a customers pcm to monitor and control fluid pressures.

What about issues that don't allow it to make it to the strip, you rely on expertise to diagnose the issue at that point?

I think it would make the world of warrant ability more level.
If the trans dynoed 750 then there should be no fault of the builder if for some reason it couldn't do that for the user. This assumes a level of honesty when the product is tested

Monkey Fist Rage
 
JWhite said:
There's one at Wyotech. We had to run our Allison trans on it after we rebuilt them. The dyno made enough power that you could lock up the converter, load it down and get them to chatter.
Click to expand...

Hell your lucky!! they were just installing that when i was there, And i am really wishing that i would have paid more attention to the allison 1000 especially since i became a DMAX guy lol

And yes it isn't cost effective, Kind of like buying a mustang dyno just to see how much you and your buddies trucks are putting out.
 
biggy238 said:
I think it would make the world of warrant ability more level.
If the trans dynoed 750 then there should be no fault of the builder if for some reason it couldn't do that for the user. This assumes a level of honesty when the product is tested
Click to expand...


I think considerations for shock-loading would negate the consistent use of a trans dyno.... if you build it, someone's going to break it. (not the scholarly response I bet your looking for, but)
 
We have one here, as well as a valve body machine. We have thought about including the paperwork in the past, and as soon as we can get everything set up I'm sure we will start including them. We basically check for pressures, making sure it's shifting when it should, making sure temperatures are not getting out of hand. Each transmission runs for about 20 minutes, that way we can get it warm and make sure it's good to ship. As for one being tested to a certain horsepower...that would probably be an issue. The cummins motor we use for example is bone stock, and running say 20 transmissions a day with a 750HP motor... we probably wouldn't have the motor for very long! That along with the fact that we would have to have a gigantic load cell to operate it with to test it to that much power. It's a nice tool to make sure everything is working properly, but not really used to test how much power it can handle.
 
Hurley said:
I think considerations for shock-loading would negate the consistent use of a trans dyno.... if you build it, someone's going to break it. (not the scholarly response I bet your looking for, but)
Click to expand...

Well, yes, but i'm leaning more toward the sacrificial destructive testing periodically.
If you have a "stage" that corresponds to a usage, then test its limits. Like a safety factor i suppose.
If it can hold 750hp, at what duty cycle?



Monkey Fist Rage
 
CookCR said:
We have one here, as well as a valve body machine. We have thought about including the paperwork in the past, and as soon as we can get everything set up I'm sure we will start including them. We basically check for pressures, making sure it's shifting when it should, making sure temperatures are not getting out of hand. Each transmission runs for about 20 minutes, that way we can get it warm and make sure it's good to ship. As for one being tested to a certain horsepower...that would probably be an issue. The cummins motor we use for example is bone stock, and running say 20 transmissions a day with a 750HP motor... we probably wouldn't have the motor for very long! That along with the fact that we would have to have a gigantic load cell to operate it with to test it to that much power. It's a nice tool to make sure everything is working properly, but not really used to test how much power it can handle.
Click to expand...

I suppose 750 hp is easier for me to stumble across with what i do.
But, you can see as how it would be difficult to claim a 750hp trans if you don't have a way to have built the power in the first place

Monkey Fist Rage
 
CookCR said:
We have one here, as well as a valve body machine. We have thought about including the paperwork in the past, and as soon as we can get everything set up I'm sure we will start including them. We basically check for pressures, making sure it's shifting when it should, making sure temperatures are not getting out of hand. Each transmission runs for about 20 minutes, that way we can get it warm and make sure it's good to ship. As for one being tested to a certain horsepower...that would probably be an issue. The cummins motor we use for example is bone stock, and running say 20 transmissions a day with a 750HP motor... we probably wouldn't have the motor for very long! That along with the fact that we would have to have a gigantic load cell to operate it with to test it to that much power. It's a nice tool to make sure everything is working properly, but not really used to test how much power it can handle.
Click to expand...

Just curious who we is? What company?
 
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