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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Cory on December 02, 2013, 08:30:31 pm
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I'm in need of a lockup kit and was wondering what some of you are using and if you had any recommendations on which kit to use or stay away from?
I still have the factory harness for lock-up but I'm pretty sure the vacuum switch will need replaced, and the male plug on the harness and female plug on the transmission will have to be replaced....plus there are two other plugs in the same harness, all connected to each other that I have no idea what they go to so I am opting for an aftermarket kit. I think it will be cleaner and easier to hook up.
I have seen the how-to on making your own kit floating around this forum, but I really don't want to use vacuum for the lockup. I then found a kit from Monster Transmissions that is vacuum free, but has a manual lockup switch you mount in the cab. I really don't want to have to mount a switch anywhere in the cab as I like it to be as stock looking as possible inside, and I just removed 30 pounds of SunPro gauges and wiring so I don't want to add another switch to the dash. I have also seen that one from B&M that uses the huge control box with the knob for adjustment and LED light and some other scientific craziness that I don't need. There are all kinds of kits from all over the place, some 19 dollars, others 160 :o what the heck is the difference??
Is it one or the other? If I use a non-vacuum kit, will I be forced to mount a switch or controller box in the cab? And if I don't want the switch, will I have to use a vacuum operated kit? I also researched the hydraulic operated lockup that doesn't use any 12V source, but haven't heard anything good about those.
I'm just looking for a simple lockup kit, preferably vacuum free unless I have no choice other than a manual switch or vacuum switch. So what are you all using and what do you recommend??
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there are kits that wire to the brake switch only (brake at rest, tc locks...press brake, tc unlocks). When doing any of these kits, you have to open up the trans to rewire the internals, I hope you understand that.
Sounds like you have the EGR bleed trans setup. You could just cut the plug out and solder the wires together. That is what I am going to have to do this spring.
I don't understand why you are opposed to the vacuum setup, it is the easiest way to transmit engine feedback to the trans on whether to lock or unlock. This is the kit from Painless Performance that I will buy when my stock goes out
(http://www.painlessperformance.com/webcatalog/plarge/60109.jpg)
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Either hook up the factory system or go with the recommendation above by Boone83K10 - I agree low vacuum response is needed to unlock the converter or you will be very annoyed
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I don't think the factory setups used the vacuum switch to unlock in fourth--it only unlocked third. If you wire your trans. through a fourth gear pressure switch to only lock in fourth you could get by without it. If you have tall highway gears (like I do) I think you'll want to add the vacuum switch. Its dead simple to install.
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I'm not exactly opposed to the vacuum setup, I was just hoping there would be something non vacuum, and without a cab switch for a cleaner look. But I think I will go with a vacuum setup like the one Boone is talking about. My question is, I dont have any 4th gear ports on the servo side of my 700r4 like I saw in a couple install videos. As a matter of fact, I only have 1 port with a plug in it, but its on the gear selector side of the tranny. I will post a picture of it and hopefully that will be it. Boone, how much is the kit your talking about? I looked it up on their website, but I have to go through a dealer in my area and none of them have websites so I'll have to call in the morning unless you know off hand...
Anyway here's the picture of the only port I have on my 700r4. Will this work for the 4th gear switch??
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Have you read this: http://73-87.com/7387garage/drivetrain/lockup.htm
The plug for the harness is at the rear of the trans between the last bolt in your picture and the next one.
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That port is for a 300 Hg/in vacuum gauge, to check for proper pressure inside the trans. The fourth gear pressure switch is inside the pan, which is why I mentioned that you have to open the trans when doing one of kits. You can buy it online through summit/jegs. Its $167, from off the top of my head.
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The later 700r4's don't have an external fourth gear pressure port, although you can make one if you drill and tap the center of the servo cover. My 700r4 is a '92 model and also doesn't have the external ports (except the main pressure port on the driver's side). I drilled and tapped my servo cover and put in an external normally open pressure switch. Without it, using the factory pressure switches it would lock up in 2nd, third, and fourth. It works perfectly, was quick and easy, and I have never had the pan off the transmission. I could have simply added a switch, but didn't like that idea. It only locks up in fourth, which is what a lot of folks prefer.