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Hi all, I am looking for advice on a lock up kit for a 700r4 box, as there are different types of kits avaliablI am slightly confused as to which one to go with, so I am hoping thet one ofe you guys who have allready done this can give me some good advice, thanks
 

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Hi Roofer,
I agree these kits can be confusing !
Two reasons for this - How comprehensive the kit is, and whether you have a 2 wire soleniod or 1 wire. You really cant tell till you pop the pan and take a look.
Its actually a very simple circuit which is just trying to acheive the activation of a soloniod valve which blocks one oil passage, giving you lock up of the converter.
In its most basic form you just need to shove 12v on this solonoid once you are in 4th and heypresto.
The so-called complexity comes with building in all the safety overrides.
These are - Brake switch - vacuum switch - 4th gear pressure switch - fuse - cold oil temp overide.
When all these overides are in harmony you should get lock up.
So basically the kit with the most parts (prob the most expensive!) is the kit to fit. It's not that hard to make up these parts yourself.
If you have any need for further clarification PM me your number and I'll call you back.
Cheers Jon
 

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All I ever used on the 700/200r4 boxes was a dash switch wired to a latching relay via the brake switch. Get up to speed press the switch and in comes the lockup, touch the brakes and it drops out. It really does not need to be anymore complicated than that.

Bob
 

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Well there are some other reasons that it does need to be more complicated than that. The reason for the need for a vacuum switch is to protect the torque converter clutch from being overloaded. It's not a manly clutch its only designed to take the load of cruising. The way you have yours wired you are able to give the car full welly in lock-up. It's not designed by GM for that to happen. As long as you are mindful then its not an issue. It would be an issue with a high power motor up a hill. It's also designed to drop out of lock-up under heavier throttle, because it anticipates you're gonna downshift to third and you should not do that locked up. I was simply restating the GM design spec which has been carefully thought out.
 

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The reason for the need for a vacuum switch is to protect the torque converter clutch from being overloaded. It's not a manly clutch its only designed to take the load of cruising. The way you have yours wired you are able to give the car full welly in lock-up. It's not designed by GM for that to happen.
I was never kind to either boxes for many years and never had problems so although I will confess to the idea being crude by comparison it does work. The 700r4 I had was in a 4x4 blazer with a 6.2 diesel and used for towing , that box ran problem free for over 5 years . Perhaps a big block with silly HP would kill one wired like this but I am not sure a stock SB would.

Bob

Bob
 

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I bought a comprehensive kit for my 200r4 from Bow Tie Overdrives after having them recommended to me.Look them up on the net,drop them a line and i`m sure they will be able to sort you out.Not expensive either.But postage may be a bother..the kit i bought for mine(done it twice now)came in with someone elses imported car.
 

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Hi, I got the B and M lock up kit from Real Steel for my 700

Some guys get away without it/modding, others the box explodes 10 miles down the road.
Personally i'd fit it as the vac signal is constantly changing and it's the only way get the thing to act as designed in a retrofit.


Also got a shift kit, put in the 'towing' setting for street and the street/strip setting for the strip. 70239

I also put in a throttle valve 70237, stops the annoying GM kick down from 4th to 3rd happening too quick.

Also fit a drain plug while you're at it 80250

The box is awesome with this stuff:smoke:
 

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biggest killer of these trans' (apart from heat) is incorrect tv cable (it's not just a kickdown cable) adjustment. this cable sets line pressure in the box as well as kickdown. without enough line pressure the box will not last. this is how art carr does it Art Carr's 700r4 tv cable adjustment guide from CPTtransmission.com. to avoid getting it wrong tci do a constant pressure valve body effectively making the cable just a kickdown cable 1987-92 GM 700R4 Constant Pressure Valve Body™ - TCI® Auto
 
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