Low stall TC and upgraded valve body?

[joecool911]

I had a new torque converter installed about 50,000 miles ago. I'm not real happy with the low stall aspects of it. When you shift into gear it hits pretty hard. My question is...if I installed a towing valve body which increases line pressure, will the shift into gear be even more exaggerated? Is this adjustable at all? Would installing a new valve body increase the life expectancy of my 47re? It's got 215,000 miles on it. I tend to baby the transmission. I don't lug it much. Tend to keep rpms higher when under a heavy load. Third question...with the upgraded valve body can I get more control of shifting? Obviously I can select 1,2 and lock out overdrive. But the control between 3rd and lockup is not available. 

[Me78569]

you are wanting what I am wanting.  

 

If you install an upgraded VB you will have more harshness in low tps situations.    

 

control over shifting is not as straight forward.  the issue is the PCM is commanding the tc lockup so if you want to control lockup you can either, disable the pcm's ablity to command lockup, or command lockup when the pcm is not commanding it.  There is no way to disable the pcm's commands when you wnat on the fly other than installing  a switch that goes between the pcm and the lockup wire.

[CTcummins24V]

When your 47re takes a dump, swap to a manual. I really hate my transmission. Low stall triple disc and towing valve body make for terrible driving around town at low throttle, as ME stated. Drives great on the highway and anywhere over 45mph. Lately I have been dropping it into 2nd going through town and it just feels like little power is getting transferred to the wheels, slushbox. I think I need an nv4500 or a lock up switch.

 

If you do a rebuild in the future, I would stay away from low stall converters and go with a stock stall or just under. My super b turbo is super laggy off the line with my current torque converter. The stock transmission drove and felt better than my built tranny, just my 2 cents. If you end up doing injectors, you will probably have to upgrade your valve body to hold the power.

[Dynamic]

With a larger than stock turbo, I'd stay at or near the stock stall speed. It will be an a smoky pig if you don't. But you'll definitely want a more efficient converter than the stock one. The stock converter is terrible...

 

Most people also choose a converter that is too tight for their application. An efficient converter with a stall speed of 250-300 rpm less than stock is perfect for most people's setups.

[joecool911]

2 hours ago, Dynamic said:

With a larger than stock turbo, I'd stay at or near the stock stall speed. It will be an a smoky pig if you don't. But you'll definitely want a more efficient converter than the stock one. The stock converter is terrible...

 

Most people also choose a converter that is too tight for their application. An efficient converter with a stall speed of 250-300 rpm less than stock is perfect for most people's setups.

I'm mostly stock. 50 horse injectors. I don't push the truck hard. Not sure what the TC is, but it was sold as a twin disc Billet. When I put the truck into gear it hits pretty hard. Will go 15 mph at idle on flat ground. Mostly wondering if a towing valve body and the increased line pressure would make the transmission last longer and if it would exaggerate the into gear slam even more? Do you do the installation with the transmission in the truck?

Edited June 6, 2016 by joecool911

[Killer223]

1 hour ago, joecool911 said:

Mostly wondering if a towing valve body and the increased line pressure would make the transmission last longer and if it would exaggerate the into gear slam even more? Do you do the installation with the transmission in the truck?

 

your getting the two confused. A built valve body with higher line pressure and other updates will most certainly help the trans last longer. Yes it can be done with the trans installed in the truck. i think it's 9 bolts holding the VB in place. then fallow the directions. what the VB does is the timing and speed of the shift. giving the allusion of firm shifts, not a more fluid shift. it shifts faster into gear. where the stock one would be nice and easy.

The line pressure is more a clutch holding feature not a shift firmness one.

 

Lower stall converters are tough to deal with on a daily driver. my newly "built" trans has a triple with a stall speed rated at 1800 for my power. the stock was 2100, i got stuck in a driveway the other day. put in reverse and it just sat there. the turbo never lit. so i had to put my programmer on 4 to get truck moving.

[Dynamic]

If a torque converter is too tight (or even defective), no amount of valve body work is going to fix that. It sounds like the converter that you put in there is either way too tight for your application, or it was defective from the get-go. None of the things that you describe should be happening with a properly built and properly configured converter. While a good towing valve body is a good idea in ANY application, it will not fix your converter issues and, yes, the increased line pressure at idle will likely cause increased harshness when shifting into gear from neutral (or park). But, like I said, this should not be the case with a good converter.

 

All aspects of shift calibration and pressure control are done in the valve body. A properly built valve body will have a modified line pressure curve (higher pressure) and reconfigured shift calibrations. There are several things that control the feel of a shift, and line pressure is a BIG one. All things being equal, simply increasing the line pressure during a shift will increase its firmness a great deal. A couple of other things that come into play are shift orifice sizing and accumulator function. These are generally changed around in a recalibrated valve body as well.

 

Increased line pressure will also hold your friction elements (bands, clutches) tighter when they are engaged as well. This is actually the main purpose for a recalibrated valve body.

10 hours ago, Killer223 said:

Lower stall converters are tough to deal with on a daily driver. my newly "built" trans has a triple with a stall speed rated at 1800 for my power. the stock was 2100, i got stuck in a driveway the other day. put in reverse and it just sat there. the turbo never lit. so i had to put my programmer on 4 to get truck moving.

 

Again, none of this should be occurring. A properly configured converter will drive little different than stock, other than having a much more efficient fluid coupling and requiring less rpm to move the truck because of it.