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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: klaussk on May 06, 2012, 05:42:33 am

Title: older VS newer 700r4
Post by: klaussk on May 06, 2012, 05:42:33 am
I got an 85 K10 with a 700r4 in it. I am putting a 406 in it with a mild cam. Originaly my truck had a 305 in it. Im worried that the  transmission wont handle the power. Im trying to explore all my options here. How much more power would an 87 to 92 700r4 handle over mine. would it be enough.  how hard is it to rebuild my tansmission with a TCI kit from summit racing. thank you
Title: Re: older VS newer 700r4
Post by: Blazin on May 06, 2012, 09:30:05 am
Takes a few job specific tools to rebuild an auto trans. The early 700R4s did have some issues, I would think that by now all of those have been rebuilt or scrapped. As far as using a newer trans I think the time and effort to swap it out you would still be no better than 50 / 50 chance its not going to hold up.If your going to swap it you might as well take yours and have it rebuilt, or attempt it your self, or just buy one that's built to handle more power.
Title: Re: older VS newer 700r4
Post by: klaussk on May 06, 2012, 01:22:53 pm
I think Im better off trying to rebuild it. Between me, my father , and my friend Marty we should have all the tools. Just gotta find them in there mess of garages haha. We should be able to figure it out and I am going to purchase the GM book for it and an instructional DVD. Buying one for the power my motor would be making is way over my budget. They run about 1200 bucks. I could rebuild it for around 350. the transmission works just fine so theres no broken parts to replace but its got 96,000 miles on it. So some parts are worn out. I have no idea if its been rebuilt before or not. As far as i know its been a farm truck for the past 10 years or so. It hasnt been run much.So its a pretty straight forward rebuild. No problem to solve. I also want to learn how to do it so its a prime oppurtinity for that. The only problem we might have is time. I will only have about 10 days to put the motor together and in my truck and rebuild the transmission. But im no stranger to working long hours. I think we can do it. Just wanted to see my other ptions and to see how much advantage a newer 700R4 would be. Thank you for the input blazin. Wish me luck.
Title: Re: older VS newer 700r4
Post by: Donut on May 06, 2012, 06:30:53 pm
You could give it a shot yourself, or you could shop a local transmission shop.  You can talk face to face, explain what your looking to do, and get a price (maybe less if you do the labor pulling it and just let them "bench build") Local warranty doesn't hurt either.

Title: Re: older VS newer 700r4
Post by: Blazin on May 06, 2012, 11:25:35 pm
You mentioned mess of a shop, one thing I can tell you is. You want just shy of a sterile environment when building a transmission.
My buddy does them. He tests all the clutch packs with air pressure, and feeler gages to see if they are within spec. The ones he is building for performance he orders thicker spacer plates to make the tolerance as tight as specs allow. Also modifies the valve body for shift kits etc.
He has a bunch of tools he only uses for trans work.
I built him a steel bench just for them so he could stand the trans upright, to disassemble, and build them.
He gets all his parts, and books from Transtar.
You will want a new torque converter as well. Tell them your cam specs, what gears you are running, what the primary use will be of the truck. They should be able to set you up with the correct converter.
Title: Re: older VS newer 700r4
Post by: klaussk on May 07, 2012, 09:57:21 am
Sounds good to me. we have a large table in thee back of the shop that we use when we rebuild motors. so I'm sure we can use it for a clean and organized spot for the transmission. I heard you can make most of the special parts needed. I'm a metal fabricator and welder by trade with access to a lathe and mill so I think I can make about any tool I might need as long as I have some pictures and measurements to go by. And stock specs should work for me as far as clearance is concerned. I'm not building a race car. Its gonna be a daily driven truck. Thank you for the input Blazin. I appreciate any advice I can get. This transmission stuff is a hole new ball game to me.
Title: Re: older VS newer 700r4
Post by: Donut on May 07, 2012, 08:41:21 pm
If your going that route, I'd also recommend the ATSG manual.  There were some things in the tbh 400 book that weren't in others.
Title: Re: older VS newer 700r4
Post by: Blazin on May 07, 2012, 10:28:03 pm
I watched him and even helped him some on many many of them. I always say I could probably do one myself, but why bother. When I need one I will have him do it!  ;D
 
Title: Re: older VS newer 700r4
Post by: klaussk on May 08, 2012, 10:51:10 am
Can I get the ATSG book at summitracing. I would like to get these books before I get back so they have to be shipped. That way I can study them alot before I attemt this.