Ive seen some setups where you can override the lockup circuit and manually control wether or not the converter is locked. Would one of these setups be advantageous in a trail rig?

the converter on a 700 will only lock up in 3rd or 4th gear above 42 mph as long as a couple of other factors are met. so unless you have a new approach to wheeling your answer is NO!:flipoff2:

I am going to do that in order to have compression braking

yeah thats what I was wondering about, but orange fj says that it only works in the 3-4 gear, so in that case it wouldnt be useful on the trail. I was under the impression that the lockup kit could be used regardless of gear that the transmission was in. Can anyone else confirm this?

My 700R$ was set up to "lock up" internally (no wires to connect) in 3rd or 4th gear only. I believe my buddies stock 700R4 in a newer truck will lock up in second gear electronically. I would guess the manuel switches would let you lock up anytime but have no experience with them.

Jason :)

it all depends on how you set it up - i had my 700 set up to lock up in 2nd (only w/ a switch), third (only w/ a switch), and OD automatically. comes in handy when in low range (4.3) and coming down something to get compression braking.

How did you rig that up?

internally or externally? externally, a few dollar switch, a relay (for brake/unlock function), some wire, and a cheap plug for the side of the case. internally - eh, don't try it alone. ;-) any 700 builder should be able to do it for you.

there is no such thing as a th700 or 4L60 that will go into lockup without any wires being attached! how's the lockup solenoid going to actuate without any power going to it?:rasta:

keep in mind that the converter will not appreciate being used as a braking device for very long! automatic transmissions are designed to propel a vehicle, not to slow it down.;)

if you are looking fo more compression braking you might want to invest in a lower stall converter.:rolleyes:

I have no data to back this up but the lock up torque converters seem to not hold your vehicle back as well as one would think. They also do not seem to pull well under high loads. Hard to tell because I'm comparing it to a Turbo 350 with different ratios. Anyone notice any difference with a non lockup converter in a 700R4?

Jason :)

well how strong in the lock up mecanism

what if ya got a TH 350C and threw it on a switch and say hit the switch in 1st and use it as a compression brake

Originally posted by orangefj45
there is no such thing as a th700 or 4L60 that will go into lockup without any wires being attached! how's the lockup solenoid going to actuate without any power going to it?:rasta:

keep in mind that the converter will not appreciate being used as a braking device for very long! automatic transmissions are designed to propel a vehicle, not to slow it down.;)

actually, you *can* set up the 700 internally to lockup in 3 & 4 automatically, at a certain line pressure, without ANY external wiring - however, i don't really recommend it.

secondly - as far as lockup to slow a vehicle down - if i can tow a 6000 lb trailer in 3rd, torque converter locked, why can't i slow the vehicle down with it at very slow speeds? i wouldn't really recommend going WOT w/ 500 hp while you're locked up, but as long as you have decent components, you're fine to lock up the TC. just remember that while locked up, you've taken away the "cushion" in your drivetrain.

remember that while locked up, the converter will not allow ANY fluid in, or out of it - and also doesn't slip at all - so it won't generate heat...

Originally posted by Chief Yelling Alot
well how strong in the lock up mecanism


eh - strong enough to tow a heavy load over a pass in 3rd... i wouldn't do any full throttle romps w/ it engaged, but it should be plenty strong for compression braking.

Originally posted by Brutpwr
I have no data to back this up but the lock up torque converters seem to not hold your vehicle back as well as one would think. They also do not seem to pull well under high loads. Hard to tell because I'm comparing it to a Turbo 350 with different ratios. Anyone notice any difference with a non lockup converter in a 700R4?

Jason :)

well - in terms of "pulling", the reason it doesn't seem to be pulling as well as a lockup, is that when it's not locked, you're gaining that torque multiplication of the TC - at the expense of heat in the converter. heat = wear. remember also that the TC only has a limited amount of flow out of it, and that if your heating rate exceeds the rate the TC can get rid of that hot fluid (easily done), you're now frying clutches and other components in your TC. i would NEVER tow anything with the TC unlocked for over a few seconds - too easy to generate too much heat.


as far as "holding your vehicle back" - it all depends on your gearing - if you have high gearing, and you lock the TC, it's gonna push you instead of slip. if you have lower gearing, it'll slow you down, until you reach the minimum speed where the engine/drivetrain will stay at equilibrium. i have a 4.3 low range w/ 5.13 gears and a 3.07 first gear - i have not yet needed a lower gear, and it sure is nice to not have to touch the brakes coming down a massive decline - like our manual/granny low brothers...

did that make any sense?

found some online schematics that show (kindof) how my tranny is wired.

internal wiring (http://www.700r4.com/Tech/TCC/TCCinternalwiring.htm)

external wiring (http://www.700r4.com/Tech/TCC/TCCdeenergizedbosch.htm)

I got one of the first batch iif not the first actual shipped 700R4 adapters short spline to convert the splines to a Turbo 350 type lentgh from Advance Adapters in the mid 80's. To date the the transmission has been in the truck more than 13000 miles. Usually around 12000 or so I would have it updated. Never had it leave me stranded except the last time but then no one except Rossi Racing transmissions had experience with high performance units back then. A-1, Art Carr, B&M etc did not touch these units yet! Rossi was doing all the LA County police cars as they were having major problems with reliability--he would rebuild them before they fried them as it was cheaper to do so--so as I understand it he did the whole fleet! Anyway mods for these were being tested and every year or two a bunch of mods became common so Rossi upgraded my trans at his cost as a test bed so to speak.
He had one in the shop 4x4 which had a big block and I had one in my 450 HP supercharged small block. At first I had a 2500 RPM high stall unit since that is what I had in my Turbo 350. I thought that the lock up clutch would give me the best of both worlds. But I was wrong as I had not driven a 700 R4 to date. I wanted neck snapping off the line accelleration and good towing ability but got neither. My truck was a bit faster off the line because of the 20% lower first gear but would not smoke the tires at the top of first gear as the torque converter did not seem to transfer power as well (well they would smoke--just not as much). And the towing ability when the torque converter unlocked was worse than the high stall in the Turbo 350 which was bad enough! So I ordered a 1200 RPM stall at rebuild time which I got at cost also!
I liked it much better but my zero to 60MPH time went up by 1 second as the engine would not flash to 2500 RPM on start up but I would get full boost and full carb richening at 1200 RPM and at this speed the tires on the truck which was full time 4wd at the time would not break the tires loose (smoke) like before so it would kind of spin lightly while black smoke came out the exhaust til the RPM got to around 2000 RPM and it started to pull clean. I did not care as it was nicer this way when towing and I still never lost any races against any other truck 2wd or 4wd! Cool to do brake stands at 1300RPM too! I know Art Carr sells non lock up
converters and I was wondering if anyone has any experience with these. I have since replaced it since an ARP rod bolt let go and I cracked the case (probably because of the lock up converter too!) when the engine locked up on the highway towing back from Hollister Hills! Back to my old standby Turbo 400-which in two other vehicles has never let me down unlike the Turbo 350 and 700 R4's! Also switched back to a NP205 so I wont be breaking cases and spyder gears in the NP203 anymore. I guess I won't be able to out drag Z-cars/Mustangs in the rain anymore w/o full time--well I'll just have to pull the shifter
and towing in the rain/ice I will have to show some restraint in 2wd! Not sure I want to drive a NP205 in 4wd with 7000lbs + in tow as something is going to have to slip and it won't be the tires!

Jason :)

Originally posted by Brutpwr

I know Art Carr sells non lock up
converters and I was wondering if anyone has any experience with these. Jason :)

i would not take an art-carr transmission or converter if it were free. both i and some friends have been there, done that, and then had to tow our vehicles home at some point to have AC's problems fixed.

If engine braking is the goal, why not throttle the exhaust?

Originally posted by nakona
If engine braking is the goal, why not throttle the exhaust?

because your torque converter is still slipping - so even if your motor were switched off, you would still move...