1st gear lock up in a 47rh

B

Biohmmwv

New member
Can anyone share information on how to modify the valve body on a 47rh to achieve 1st gear lock up?
I am kicking around the idea of putting together an Adrino and having it control lockup in each gear along with pulling on the TV cable to delay the shift before unlocking the converter, releasing the TV cable then locking back up.
I currently have manual 2nd gear lock up and have been unlocking the torque converter just before the transmission shifts to 3rd. but I need to know how soon lockup can be engaged in first without lugging the engine, or having too much of a drop in RPMs.
I want to see if I can get away with not going to an aftermarket torque converter just to have the tighter stator.
I'll be building a spare 47rh transmission with a 48re Stator and pump gear for increased flow. Hopefully, the pump upgrade (along with higher line pressure in the valve body) will provide enough pressure for low rpm engagement of the lockup.
So, a description and picture of what needs to be done for 1st gear lockup would be appreciated.
 
I really don’t see a use for 1st gear lockup unless you are Wheelin... have you checked out my thread on electronic conversion of the 47rh?
 
I don't want to covert my hydraulic unit to electronic. I like not having a computer control the transmission.
What I am after is hopefully doing away with the need for a low stall converter.
 
“I am kicking around the idea of putting together an Adrino and having it control lockup in each gear along with pulling on the TV cable to delay the shift before unlocking the converter, releasing the TV cable then locking back up.”

“I like not having a computer control the transmission...”

:bang
 
I like the TV modulation idea. I'm not sure how practical it is in the long run.

Be careful about how you get your speed signal. I killed an arduino by designing a faulty circuit.

Sent from my XT1575 using Tapatalk
 
I was planning on using governor pressure for the speed signal since it is supposed to be about 1psi per 1mph. Then I would use the pressure ports to tell the Adrino if the a gear was already applied.

I like the 47rh as I could releasable have it computer "assisted" and still have a hydralic backup if there were a systems failure.
Reading comprehension is important Redrider2911
 
A 47/48 with lockup in first gear results in much engine stalling and greatly increases drive train issues for anything behind the convertor. I would not recommend.
 
My idea was to get the truck moving a little before lockup engaged.
I just don't know how many RPM it will drop with moderate throttle pressure.
2nd gear( which is the gear one usually takes off in while unloaded) in an NV4500 is 3.0 to 1 whereas 1st gear in the 47rh is 2.45 to one. It will take a little more forward movement before lockup can be engaged.
Basically, like slipping the clutch ( bad practice in a manual) longer in a manual transmission.

joefarmer said:
A 47/48 with lockup in first gear results in much engine stalling and greatly increases drive train issues for anything behind the convertor. I would not recommend.
Click to expand...

So, you're saying the transmission can't handle the power through it?
joefarmer, do you know where to get the instructions on how to do the mod on the valve body and can you share the info?
 
How many rpms does it drop when it does into lockup? That is a locked hard gear shift. Expect that through all gears. It will he violent to say the least.
 
The RPM drop depends upon throttle input. I make a habit of getting off the throttle just before it shifts, and I unlock the converter when it is in second gear and it is about to shift into third.

If I'm reading your question right, there is a 200-400 rpm drop (depending upon throttle pressure) when it shifts from 3rd locked to 4th unlocked. There is a 400-500 rpm drop when it goes from 4th unlocked to 4th locked.

When taking off from a stop the RPMs are 1200-1500 when it starts to move on flat ground. on a hill with my foot in it the RPM can get up to 2100.
 
Another thing, the shifts are predictable. At 20mph the trans will shift to 2nd gear then to 3rd gear at 30mph.
 
There is no such thing as 4th with nonlock up. That gear only exists when the converter is locked. 1,2,3,3lu,OD
 
every 4 speed 47rh or re i've every owned shifts 5 times not 6. cut the lock up wire and OD doesn't happen. you just get 1,2,3. fix the lock up solenoid and you get 1,2,3,3lu. fix the od solenoid and you get, 1,2,3,3lu,OD. making your 3 speed OD transmission feel like a 5 speed.
 
turbo2387 said:
every 4 speed 47rh or re i've every owned shifts 5 times not 6. cut the lock up wire and OD doesn't happen. you just get 1,2,3. fix the lock up solenoid and you get 1,2,3,3lu. fix the od solenoid and you get, 1,2,3,3lu,OD. making your 3 speed OD transmission feel like a 5 speed.
Click to expand...


My 47RE on 97 dodge. Shut OD off, you get 1, 2, 3, LU. Hit OD on, it unlocks, then you get OD, then LU. This is IIRC correctly. The standard shift strategy I believe is as your saying, however(again if memory serves me correctly) there is no hydraulic reason that OD needs LU, and LU needs OD.
 
turbo2387 said:
There is no such thing as 4th with nonlock up. That gear only exists when the converter is locked. 1,2,3,3lu,OD
Click to expand...

Wrong. Let it shift normally into 4th gear, it will almost instantly lock up so you might not notice it. Then roll into the throttle on a decent grade. You will feel the torque converter unlock and the rpms raise a little bit all while in 4th gear.
 
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