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Discussion Starter #1 (Edited)
I'm currently reviving a 1968 Corvette 350 cu.in 300 H.P. It currently has a TH400 transmission installed which shifts perfectly, but does not have the Overdrive gear or the Torque Converter Lockup.
I have already modified a TH700R4 for my 1934 SBC 350 cu.in. street truck, and it has shifted perfectly.
I realize I can install a base 4L60 or a TH700R4 with no problem, but I can get a great deal on a 4L60E.
Also, the 4L60E has the gear ratio I would like to have in the Vette, which only weighs 3500 lbs.

There are dozens of internet videos about converting the 4L60E to be shifted Manually by rewiring it for a floor shifter, but no one has been able to solve the EPC Force Motor rewiring problem.

THE MAIN REASON FOR REWIRING THE 4L6OE Force Motor so it will Operate correctly IS TO AVOID RUINING/DESTROYING THE TRANSMISSION BECAUSE OF CONSTANT FULL LINE-PRESSURE WHICH CAN LEAD TO TRANSMISSION FAILURE OVER TIME BECAUSE OF HARD SHIFTS.

Problem #1 concerning the TCC PWM Solenoid(valve) can be solved by modifying the end of the valve body or the internal orifice diameter to a larger diameter so fluid can reach the Torque Converter Clutch at a faster rate which will engage the torque converter without "slamming the clutch" into full lockup (which would happen with Full Line-Pressure)

PROBLEM #2 IS MY HOLD-UP concerning modifying the EPC Force Motor. It DOES seem to require an in-vehicle computer to operate properly because of the low-voltage/ cycle-signal it receives from the vehicle computer. which causes the Force Motor to cycle On and Off about 30 times a minute in order to control shifting pressure.

My plan is to rewire the EPC using a relay/resistor/etc to cause the EPC to function as though a in-vehicle computer is sending signals to the EPC.
MY PROBLEM is that I have limited knowledge as to how the relay/resistor/potentiometer can be wired to the EPC to make it operate correctly.

The Vette is "UNDER CONSTRUCTION" at the moment"
 

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Discussion Starter #3
Thanks for the fast reply '48 Austin! I read the article three times just to be sure
I'm on a limited budget which is the reason I'm trying to DIY the 4L60E wiring.
If I find that it is impossible to rewire the Force Motor I will find a 4L60 or a TH700R4 and rebuild it, rather than invest $600-$1,000 in a stand-alone controller/TPI/Etc., plus a rebuild kit into a "E" transmission.
I will post results here whichever route I choose...maybe it will help other members who are doing "E" transmission swaps.
Thanks again, doorgunner
 

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Discussion Starter #5

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You're much better off just getting a 700R4.

Besides the controller, you'll need a Throttle Position Sensor, and then you have no speedo, so you're looking at another $300+ to make your speedo work.
So now you are up to $1000 extra...
For something that you're just making 1/4 mile runs, I could see doing the mod harness/switches thing.
But for a street cruiser, it would be a pain in the ass... and you won't have a speedo... unless you at least spend the cash on a speedo converter.

I have a 4L60e, and I bought a U.S. Shift Quick 4 controller (585)... and harness (140)... and TPS (175)... and a speedo converter (300).
I love the way it works, the programmability and features etc.... but I cringe every time I think of the cost.

If you're on a tight budget, I'd seriously try to find a 700 at a reasonable price.
 

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Discussion Starter #9
You're much better off just getting a 700R4.

Besides the controller, you'll need a Throttle Position Sensor, and then you have no speedo, so you're looking at another $300+ to make your speedo work.
So now you are up to $1000 extra...
For something that you're just making 1/4 mile runs, I could see doing the mod harness/switches thing.
But for a street cruiser, it would be a pain in the ass... and you won't have a speedo... unless you at least spend the cash on a speedo converter.

I have a 4L60e, and I bought a U.S. Shift Quick 4 controller (585)... and harness (140)... and TPS (175)... and a speedo converter (300).
I love the way it works, the programmability and features etc.... but I cringe every time I think of the cost.

If you're on a tight budget, I'd seriously try to find a 700 at a reasonable price.
Thanks...You Members are giving me good advice from all angles. I was hoping to discover a way to DIY the Force Motor on the 4L60E without "taking out a loan". Installing a different solenoid-Valve would be an option in order to eliminate the Force Motor.
Also, I was trying to avoid the TH700R4 because they have been picked thru for the most part. Next would be the 4L60 Base transmission/no need for $$$$ add-ons.

Basically, I'm stuffing the piggy bank to finish the quality paint job on the front clip.

I'll update as I settle on a direction/choice of transmission.
 

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Pick over, what do you mean ? There are tons of 700R4 builders and suppliers out there.

There is no means (at least no simple means) of modulating the 4L60E without a controller device. People that build these and 4L80E’s for manual shifting live with max pressure shifts when using them without a controller.

When the 4L60E in my truck died I put a 700R4 behind the 350 and put a carburetor on top of the 350 and ripped the computer and all the ugly wiring out.

Bogie
 

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I have a 4L60e, and I bought a U.S. Shift Quick 4 controller (585)... and harness (140)... and TPS (175)... and a speedo converter (300).
I love the way it works, the programmability and features etc.... but I cringe every time I think of the cost.
Who charged you $175 for a TPS?

Even having a "bolt in" adapter bracket of some type. Thats $100+ for a piece of aluminum.
I could see paying that if it was the actual DBW TPS pedal and bracket. But for a TPS on the side of a carb that seems high.
 

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Yeah U.S. Shift does charge alot for the Edelbrock TPS.
Their Holley TPS is $100.

I don't think I paid quite that much a few years ago, but that's the current prices.
 

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Discussion Starter #13
Pick over, what do you mean ? There are tons of 700R4 builders and suppliers out there.

There is no means (at least no simple means) of modulating the 4L60E without a controller device. People that build these and 4L80E’s for manual shifting live with max pressure shifts when using them without a controller.

When the 4L60E in my truck died I put a 700R4 behind the 350 and put a carburetor on top of the 350 and ripped the computer and all the ugly wiring out.

Bogie
Picked over refers to salvage yards, as the budget doesn't allow for purchase of a rebuild when I can do it myself for the cost of a rebuild kit. I'm with you on the TH700R4 / I put one in my '34 street truck / worked perfectly 3rd + O.D. /4th + O.D. I'm working on a 0 to 1.5 amp regulator to wire into the Force Motor power wire to avoid constant full line pressure..if it doesn't function properly the 4L60 (non-E) would be my next choice...then the TH700R4.
Thanks for the info...it won't go to waste!
 

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4L60 no E is a renamed 700R4. But there are many internal differences over the production years. The 1987 and up are considered the best builders.

The 4L60E suffers through a lot of production changes as it creeps through the years as well. The 1995 being considered an oddball year.

They all share many common structural strength problems and heating issues in performance use.

I think your idea on controlling the modulator has merit but many of these solenoids are Pulse Width Modulated rather than using variable power regulation. I just don’t recall which this uses. I’ll have to dig through my notes.


Bogie
 

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Discussion Starter #15
4L60 no E is a renamed 700R4. But there are many internal differences over the production years. The 1987 and up are considered the best builders.

The 4L60E suffers through a lot of production changes as it creeps through the years as well. The 1995 being considered an oddball year.

They all share many common structural strength problems and heating issues in performance use.

I think your idea on controlling the modulator has merit but many of these solenoids are Pulse Width Modulated rather than using variable power regulation. I just don’t recall which this uses. I’ll have to dig through my notes.


Bogie
Thanks Bogie. I can try to make a voltage regulator/potentiometer for the low amp low voltage Force Motor Solenoid OR find a replacement Solenoid/Valve combo that will operate off 12volts much like the
TH700R4/4L60 transmission.
I don’t mind feeling the torque converter locking. If you have notes related to the above modifications that would be great.
doorgunner
 

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The 700R4/4L60 is mechanically controlled, that starts at the push/pull cable that attaches to the EFI or carburetor throttle bell crank and extends to a bolted connection on the right, outside case casting. The push/pull cable inside hooks to a mechanical valve. This controls pressure modulation and forced kick down shifts.

The electrical connections on these transmissions is for all of them the converter lockup, the factory uses vacuum switches and a brake application override that allows lockup in second through fourth gears. The vacuum switch prevents lockup at low vacuum typical of open throttle as the converter clutch is not sufficiently strong to carry maximum power transfer. The other wires, if present, would be for electric speedometers that came into use on different models in the late 1980’s early 1990’s. These are a twisted pair, usually green. The 700R4/4L60 can be dressed for an electrical or conventional mechanical speedometer. The 4L60E can be converted to mechanical but is a lot of work, it can also use an external electrical to mechanical converter


The 4L60E moves these functions as well as normal shift sequencing under electrical control commanded by the computer. The computers vary across years and models moving from discretely managed functions with individual chips and in some cases separate modules for engine, transmission, and housekeeping to integrating these functions as life moved from early OBD-I to the ever advancing OBD-II which feeds into various lines in the early, mirish 1990’s to full commitment by 96.

The 4L60E has many of the same physical strength problems of the 700R4/4L60, most of these get fixed across time to the present but basically any of these short of 2001 or so need aftermarket parts to beef them up for performance or heavy duty use.

GM working in odd ways put fixes and improvements on low production, low profit margin Corvettes first and high production, high profit trucks that really needed these fixes last; go figure?

Bogie
 

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The 4L60E has many of the same physical strength problems of the 700R4/4L60, most of these get fixed across time to the present but basically any of these short of 2001 or so need aftermarket parts to beef them up for performance or heavy duty use.
Fortunately he doesn't have too much HP, so clutch upgrade and other minor "fixes" should be all that's required.
 

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Discussion Starter #18
Fortunately he doesn't have too much HP, so clutch upgrade and other minor "fixes" should be all that's required.
I happy with 300 h.p. The car is/will be used for road trips and weekends.
Fortunately he doesn't have too much HP, so clutch upgrade and other minor "fixes" should be all that's required.
300 hp is all I need. Any more than that I get stupid with the gas pedal.
 

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I wasn't criticizing your HP, I was just saying that just HD clutches should be all you need.
There are some other "fixes" that should be done as well, regardless of HP.
There's a shop manual that covers the "updates".
 

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I wasn't criticizing your HP, I was just saying that just HD clutches should be all you need.
There are some other "fixes" that should be done as well, regardless of HP.
There's a shop manual that covers the "updates".
Thanks Bogie. I can try to make a voltage regulator/potentiometer for the low amp low voltage Force Motor Solenoid OR find a replacement Solenoid/Valve combo that will operate off 12volts much like the
TH700R4/4L60 transmission.
I don’t mind feeling the torque converter locking. If you have notes related to the above modifications that would be great.
doorgunner
Trans go makes a kit to eliminate the EPC.You remove the solenoid and replace it with a sleeve,valve, pin and a modulator.Drill Hole thru the case and connect to engine vacuum.It now controls pressure according to vacuum like the older transmissions.They also give you a resistor to connect to the EPC connector,that you only need if you are using a computer.
 
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