As I got closer to installing my 47RH, I turned my attention on how to control lock up. These can be used with an type of OD control with only some fine tuning. I had to keep this an automatic system because the wife drives the truck.
The first diagram assumes that lock up can occur in any gear. It uses a B&M speed based lock up controller, an adjustable boost over ride switch, and an adjustable "delay on" relay. The B&M turns the system on at whatever minimum speed you set. The boost over ride acts as a part throttle unlock. The delay on relay acts as a buffer to prevent rapid cycling if you are running on the edge of your adjustments.
The second diagram assumes lock up can only occur in OD. It uses the boost over ride switch and delay on relay only, "piggy backed" on the OD control and operates in the same manner except OD triggered instead of speed triggered.

B&M lock up control p/n 70248 from Jegs $150
Adjustable pressure switch from Transducers Direct $50
Delay on relay from Allied Electronics $30

 

"OK, I'm confused or need more coffee. So do I hook it up like step 1 or 2??
Michael"

One or the other depending on how you want to control it.

" kensmachine wrote:The stock valve body in my 47rh wont down shift if the toqur converter is locked up so you need to ask your trany guy if changed it so it will. Its a PITA I need to get the valve body out and get this fixed.Ken"


I was hearing different reports on this. Some saying yes it will, some saying no it won't. So i figured it out both ways just in case.
:!: If it won't down shift? Hum, that is were the boost switch will come in. Unlocking the TC over your set pressure for power down shifts.
For deceleration down shifts adding a brake switch interrupt will work. It will momentarily unlock the TC restarting the clock on the "delay on relay" giving you time to down shift before re-lock. And/or some fine tuning on what speed the B&M engages the lock up.
Thanks Ken

" txs wrote:There is a way to use 48re valve body parts (i think it is the lower body steel separator plate and leave out a ball but i will have to check for sure) to allow your 47 to go into lockup in any gear. As 47s are from the factory there is no hydraulic pressure available for lockup switch valve in 1st and second."


Good information, thanks! For my application, 3 and 4 lock up would be just fine considering it will be doing a lot of towing. I know others would like to have at least 2 and up available for lock up.

 

is lockup strictly for performance or will this type of mod make the tranny last longer?

 

Here's what I was thinking...

How about use the factory OD control. Leave it in place and add the relay/boost and brake light switch to trigger the tc lockup. How long in the delay timer?

I was thinking to prevent short TC clutch life, not having it try and lockup under high-boost would be goodness.

M

 

I'm also interested in how to control lockup in every gear. I've got a 47rh I'll probably be putting in soon. I've heard they only lockup in OD stock? is that right?

 

IIRC, from what a couple of tranmission rebuilders have told me, there's a 2 stage system to lock-up.
When in drive, valve body pressure trips a valve, to allow engagement of the lock-up circuit, much as it allows the overdrive to function.

The interesting thing is that you can have lock-up in BOTH manual drive (O/D off) and O/D (on).

Lock-up will not function in 1st or 2nd gear, this I know from trying to bypass it years ago.

Mark.

 

Both diagrams use the original OD control. I figured on setting the delay on relay for about 10 seconds. Should be long enough to prevent cycling.
If you don't have lock up in all gears, use the second diagram.
If you can, use the first.

 

Mark,

Maybe the rebuilders are talking about using 2 pressure switches to trigger the OD and TC lockup. Info is on this site- not a big deal.

Cougar" What p/n is the delay relay from Allied Electronics? Which boost sensor did you purchase?


Michael

 

I didn't want to tap into the transmissions hydraulics because of the possibility of getting it broke off in a good bounce.
The transducer is a TDPS123CW. This one has 1/4" pipe threads, they were out of stock on the 1/8" one. Range is 6-30psi.
The relay is an Amperite 12DNO.1-60C. Range is .1-60 seconds. You can use any relay provided it has separate contacts for the load.
I'm not sure if the ECM will handle the load of 2 solenoids as in diagram 2, so I'm opting to install a 30A relay to supply a ground instead of going through the ECM. So the ECM will be grounding 1 relay instead of 2 solenoids.

 

Dunno' what this comment means, but I'd appreciate it if you shared where this info is.

Mark.

 

Mark, it's in the FAQ sticky under powertrain. That one shows only for OD, but you add a second switch of a higher speed for lock up.

 

Here's what I'm planning- I'm using my TPS setup, to trigger the delay relay. So, the TC locks up about 6-60 seconds after the OD engages. Somehow, I think it would be nice to have it cut-out when braking and not engage under heavy boost.

Cougar: How do you like the setup you are using??

M