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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: CHawk on July 24, 2007, 10:41:20 am

Title: 700R4 Compatibility
Post by: CHawk on July 24, 2007, 10:41:20 am

I've got an '85 K10 SWB.  I pulled the 305 and have a 350 ready to go back in.  My 700R4 tranny also had serious issues before the 305 quit ie overdrive quit.  I was going to have the tranny rebuilt again (last rebuild was back in '93).  But...searching craigslist I found a 700R4 from a '91 4WD truck.  As I understand it, that should be a stronger version with all the factory upgrades, etc.  But I've also heard that it has connections for the ECM?  Can I still install this tranny in my non-computer '85?  Any help would be appreciated!

Thanks!

Chris

Title: Re: 700R4 Compatibility
Post by: DnStClr on July 24, 2007, 11:33:11 am

I can help a little but I think you'd have to get a 2wd tranny instead of a 4wd. You can install the 700R4 into a non-computer truck. But you need a kit to manually control lockout in 4th gear. That's what the computer does for you automatically. You definitely want lockout. It keeps the tranny torque converter running cooler. The kit consists of a switch and wiring. Hope I've helped a little.
 Here's a link for ya-http://www.high-impact.net/transmission_and_gear/badboy700r4.htm (http://www.high-impact.net/transmission_and_gear/badboy700r4.htm)

Title: Re: 700R4 Compatibility
Post by: CHawk on July 24, 2007, 12:18:09 pm

Thanks for the quick response!  Now that you mention that, I recall a buddy of mine talking he had to wire a switch such as you describe after putting a police intercepter 350/700R4 into an older 70's Caprice.

Quick note though...my truck is a 4WD and the new tranny is a 4WD; shouldn't need to get a 2WD tranny, right?

Thanks!

Title: Re: 700R4 Compatibility
Post by: dumbucket1 on July 24, 2007, 12:57:20 pm

no you don't need a 2wd tranny, he assumed you had 2wd since you did not specify.

Title: Re: 700R4 Compatibility
Post by: Captkaos on July 24, 2007, 02:22:37 pm

If your current truck has a 700R4 it will already have the lockup control on it, just verify that the connector going to the trans is the same, if it isn't, you can swap it.  A 700R4 is not computer controlled.

Title: Re: 700R4 Compatibility
Post by: CHawk on July 24, 2007, 05:19:07 pm

I indeed have a 700R4 now...

If my truck doesn't have an ECM, where does the current lockup control run to?

Thanks for all the help!

Title: Re: 700R4 Compatibility
Post by: Blazin on July 24, 2007, 06:39:52 pm

He did specify he said 85 K10. I could be way wrong but the 85 valve body might be a better mate to the ECM in your truck. A 91 would most like;y have a 4L60 or 4L80E trans. and a 241 T case. Is the output shaft the same diameter and spline count as the 700R4?
 

Title: Re: 700R4 Compatibility
Post by: VileZambonie on July 24, 2007, 08:20:57 pm

91 4L60 should plop right in there

Title: Re: 700R4 Compatibility
Post by: Captkaos on July 24, 2007, 11:54:41 pm

1982-1992 (and part of 1993) 700R4's (refered to as the 4L60 in 1990) are all the same as far as bolting up.  The electronic version 4L60E started in 1993.

Title: Re: 700R4 Compatibility
Post by: DnStClr on July 25, 2007, 01:04:15 am

I have no idea why I missed that description of your truck CHawk. It was the 1st thing you said.  Anyway, the right answers showed up .  ;D

Title: Re: 700R4 Compatibility
Post by: CHawk on July 25, 2007, 09:35:31 am

No prob at all!  I have trouble finding my keys two feet in front of me sometimes!

Thanks everyone for all the help.

Chris

Title: Re: 700R4 Compatibility
Post by: Blazin on July 26, 2007, 07:02:28 am

I wasn't being a jerk, just figured if someone else missed it and read there was no description in a reply they might type a bunch of stuff for nothing is all.
 I lose my sun glasses when they are on top of my head!!