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-   -   Stall converter (http://www.wranglerforum.com/f282/stall-converter-132484.html)

91badass 01-11-2012 08:31 AM

Stall converter
 
Has anybody with an automatic transmission used a 300 to 500 over stock stall converter to help with that forward dig when going down steep grades/hills while on the trail, I find the only down fall to an automatic trans is no clutch! always on the brakes. Let me know..
thanks Ed

rrich 01-11-2012 01:06 PM

Raising the stall speed would make downhill decel worse.
Lowering it would make it hard to drive and hurt acceleration..

But - if you have a lockout converter some folks put a switch to lock it when going downhill. Simple and easy. But you have to remember to unlock it when you stop - else the engine stalls. Not quite as good as a clutch, but "less worse."

91badass 01-11-2012 04:13 PM

When going down a steep hill and your all over the brakes because your already in 4 lo, and the vehicle just wants to go, it seems if you made it so the transmision would not tranmit torque until you wanted it, ie pressing the gas pedal than all you would have to deal with is gravity, your gears would hold you back, so as to not be the same as driving in neutral, the only reason im on this is it is a problem i have and i read about it somewhere, the only downfall being higher trans temps.

ipleadda2nd 01-11-2012 04:39 PM

It makes sense to me that a higher stall torque converter would let you coast down a hill better. But why coast when you can use the engine to slow your decent?

If you put it in first gear going down that hill, the engine would slow your decent. It does for me. And it would even further slow you down if you got the torque converter to lock (what a great idea). That will save your brakes.

jgorm 01-12-2012 09:51 AM

As mentioned a higher stall will make engine braking less unless the converter is locked (then stall speed is irrelevant). Locking the converter usually results with 10% more force transmitted. Make sure the shifter is in the lowest gear needed for the decent.

srad600 01-12-2012 10:25 AM

Quote:

Originally Posted by jgorm (Post 1913724)
As mentioned a higher stall will make engine braking less unless the converter is locked (then stall speed is irrelevant). Locking the converter usually results with 10% more force transmitted. Make sure the shifter is in the lowest gear needed for the decent.

:thumb:

91badass 01-12-2012 10:52 AM

Got it, thanks fellas.

rrich 01-12-2012 11:42 AM

An automatic is just a solid gearbox with the converter. The converter does all the slipping. Lock it, and you are back to just solid gears.

The good thing about it is the auto has a higher gear ratio (numerically) than the manual, giving even more engine braking.

Of course put it the lowest gear - you would if it was a manual trans too.

The PCM sends a signal to the converter to lock it - but only at higher speeds.

I forget whether you use the manual switch to ground the terminal on the trans, or send (+) to it to make it lock. Look at a FSM to find the connector and polarity.

It's a very simple yet effective mod.

jrussblues 01-12-2012 01:45 PM

I put mine in 4lo auto 1st and use the little bit of engine brake that provides. If I'm light on the brakes, it usually works out well.

Jerry Bransford 01-12-2012 01:48 PM

What is your axle gear ratio? I run an automatic and between my 4.88 gearing and 4Lo, I have to give my Jeep gas to keep going fast enough downhill. Mine will usually go slower than it needs to on even scary-steep stuff.

rrich 01-12-2012 04:15 PM

Jerry with your gears, and the Rubicon's low t-case it probably wouldn't be of much use to you. That in combination with 4 wheel disc brakes it isn't a problem. Most of the time on the really steep ones you'll brake traction and slide.

But not everybody has your gearing or 4 discs.

I don't need it either - 5 speed manual and 4 discs..
But that's one reason I prefer a manual trans - LOL - and my left foot doesn't feel "guilty."

But I'll bet you do have a switch to use your lockers in other than just 4 LO and under 15 MPH. Sometimes it's the little things that make a big difference.
I keep saying I will, but never do - i want a switch on my lockers so I can use only the front locker without the rear.


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