Are you rebuilding these unints?
If so...why oh why are you even bothering with the transgo multi layer plate?

 

I am, because I'm dumb haha, I've been doing it because I haven't had an opportunity to run one for myself with the standard dual feed modification. Now that I have the ability to run them I'm doing it different. Luckily I don't install the seals on the drum or center support so the trans doesn't have to come apart to correct my dumbness.....

 

Did you drill a bleed hole in the direct drum?
That can show itself in a line pressure test...usually not 40 psi...but some

I'd toss that junk transgo plate in the garbage. Save you money and headache

 

I didn't drill the drum, these are for fairly low rpm setups. I have seen the results from the bleed hole and have seen maybe 5 or so psi variance. I really think it's that plate that's the issue, just really wanting to see if anyone can shoot holes in my tests to arrive here. I am not defending the use of the transgo plate. I have heard of these issues for years but I couldn't get comfortable with modifying the hydraulics to go without it unless I would be there for initial setup on the unit, and that was never a possibility so here I am. I'll be swapping in a stock plate with the feed holes drilled later today so I'll have my results, just if anyone see's an issue call me out please!

 

Is the governor land on the mod valve active?


Hutch

 

The only hydraulic modifications made were part of the transgo pro kit, still uses governor. So I would assume right? If what you’re asking is does it still have the governor in use then yes

 

I'm asking if the mod valve is stock. If so it will contribute to lower 3rd gear oil pressure.


Hutch

 

Yes it is, the only modification to it is a very light spring is installed on it. So this is normal?

 

Remove spring first. Try it. If you have a sacrificial valve, grind a flat on big land to test. See what it does and how it acts.
Then if you decide that's what you want, go plug the leak you created.


Hutch

 

Hutch, I follow the instructions your giving, but you lose me when you say go plug the leak you create. Are you meaning that I'll see something I like when I grind the large land flat but then I'll have to put a stock modulator back in? Is this part just for a test purpose that won't actually work for this type of build?

 

If you look at the circuit, you will understand. For current test purposes we need a sacrificial mod valve modified to properly diagnose the situation.


Hutch

 

Ok, I'll iron out my other issue in my other post on the stand and get to testing, thanks again

 

How did dyno testing go?


Hutch

 

I haven't been able to put it back up there yet, I have family coming in for a couple days so I left the other unit on there with the boost valve I posted the question about. I had about 10 minutes to mess with it last night so I dropped the regulator assembly out and was very excited to see it has the small boost valve in it (my mistake for not measuring, I learn by bumping my head it would appear). So I swapped to the larger factory boost valve in that, I'll be able to run it Saturday, get it out of the way, then I'll get this one back up there and see what's up. In other news I came across a tech article that makes me understand why you ask about if the governor circuit is still active, makes me wonder how any of these auto shift units live with any real horsepower in high gear.

 

I'm subsribing to this thread.....We have a fully automatic governor shifted TH400 in our race car (low 10's). We installed a datalogger in the car last year and was surprised at the driveshaft rpm (long and drawn out) at each shift point. We had several racers look at the data and all agreed something was not right. We pulled the transmission and had the builder go thru it this winter. He noted burnt clutches (the clutches located directly behind the pump....sorry I'm no transmission expert...lol) and said something was not right (the transmission only had 25 runs on it). The builder put it on the dyno and noted the large pressure swings from 1-2 & 2-3. They performed a modulator valve modification along with replacing all the items that showed wear on their dime as they said it should have never left this way. Hopefully we will be racing in the next couple of weeks and can report back our findings.
The reason I'm writing this reply was because we thought we had a torque converter issue. Several converters by several different companies and the timeslips always showed the same thing (the converter showed a high slip %). Maybe it was the transmission all the time and we assumed it was a converter issue.....

 

I'm subsribing to this thread.....We have a fully automatic governor shifted TH400 in our race car (low 10's). We installed a datalogger in the car last year and was surprised at the driveshaft rpm (long and drawn out) at each shift point. We had several racers look at the data and all agreed something was not right. We pulled the transmission and had the builder go thru it this winter. He noted burnt clutches (the clutches located directly behind the pump....sorry I'm no transmission expert...lol) and said something was not right (the transmission only had 25 runs on it). The builder put it on the dyno and noted the large pressure swings from 1-2 & 2-3. They performed a modulator valve modification along with replacing all the items that showed wear on their dime as they said it should have never left this way. Hopefully we will be racing in the next couple of weeks and can report back our findings.
The reason I'm writing this reply was because we thought we had a torque converter issue. Several converters by several different companies and the timeslips always showed the same thing (the converter showed a high slip %). Maybe it was the transmission all the time and we assumed it was a converter issue.....

Check your messages

 

Test results are in and we have the same line pressure in all ranges after grinding that flat. I like the numbers I’m seeing. I will have the opportunity to be part of setup in the vehicle on this one so I’m going to send it out. Last question is to Hutch, you said fix the leak I created, can you share if there’s anything else I need to do before this leaves this way. Thanks again

 

The flat opens a leak. Find the feed to it and plug it in the plate. Did you do a test without the spring before you ground the flat to see the contribution to each?


Hutch

 

I did not, but I can still as I left it on the dyno until I get things figured out. Once I plug the plate this modification is no longer necessary it would seem right? What’s the easiest/best way to plug the plate?

 

Makinchips, sorry, not seeing anything, you send something?

 

Currently you can install a stock valve and it functions.
Once you plug the hole in the plate you can't back up as you have created a valve that is trying to work in a sealed compartment. It will be hydraulically locked.


Hutch

 

Apologize if I’m being dumb here, but it seems you are saying leave the ground one in there if I plug the plate?

 

Yes, but you seem like your trying to learn so getting you to the area of concern and letting you figure it out is all I'm doing. Next is whether or not the vehicle likes it that way as they sometimes get throttle sensitive without governor oil acting on the mod valve. So if you look at my first post I suggested an order to test on your dyno and suggested having a sacrificial valve on hand.

Maybe try it as is with the leak in the car VS with the modified valve. Once you are sure of the direction, pull the vb and plug the hole and see how it reacts to that as that is a governor oil leak.

If this is too much once it is in the car , you can just plug the plate hole now and hope for the best.


Hutch

 

As I actually think about it that makes sense, so ground one would make sense to allow it to still move

 

Hutch you nailed it on what we’re doing here, I appreciate the steps you had me take because it made me stop and learn what I need to. I left it on the dyno yesterday so I am going to test with a stock valve and no spring. That tech article I read said what you just said but in less detail so on builds I won’t be there for installation I won’t be comfortable sending them this way until I’ve done a few. I really appreciate the input you gave on this one, once again very eye opening

 

For test purposes before I pulled it last night I put a stock modulator valve back in with no spring. It kind of split the difference at lower engine speeds, then came to about the same result above 2800 rpm or so (keep in mind this is completely unloaded on the tailshaft). I'll have to get back to these test results when I have a little more time however, the trans is going to a buddy that owns a hot rod shop for one of his customers with a 400 horse C10 and dude isn't waiting any longer. I decided to send it as is, we will not have the time to fool with it the way we will need to once it's in the truck. I told him next time we have one of these builds schedule me an extra evening in there. I will follow up on this with the results so anyone curious gets the info and Hutch can shoot some holes in it so I can continue to learn my hydraulics. Thanks again for everyone that chimed in.

 

Stock with no spring will be great.


Hutch

 

Awesome! On that note maybe someone can enlighten me on some theory here. I was surprised to see the line pressure I found as I have a lot of these out in service, a few I have had back apart for various reasons, that are in 600-650 horse applications with cherry looking clutches after quite a bit of usage. So first off, why on earth would it be a good idea to put a spring on there? What is being accomplished in a performance driven shift kit by adding that. Also it would seem the only necessity to go down the road this testing was taking me down is if you put an auto shift style trans in an environment that probably should have a manual valve body and constant line pressure horsepower/abuse wise, or is that off base?