1986 700-r4

[Calclips]

I found an 86 K5 for sale close to where I live with a good body for living in Michigan its whole life, but it has a 700-r4 tranny. This isn't a big problem for me as I don't do anything very hardcore, but I know that older 700-r4 were big piles of crap. Is a 700 from 86' gonna be one thats fairly reliable, or is it gonna be problematic. ( I don't think the blazer has seen much or any offroading because it sits the stock height with stock tires, so that hopefully means less tranny wear)


Anything I could check when I'm looking at the blazer that could clue me in to any major mechanical problems (aside from obvious visible leaks/smells)

 

[azblazor]

There seems to be a difference in opinion as to where the break is, i.e. after 85 are OK, after 87 are OK, after 88 are OK. Those three years I see referenced most often. We just salvaged a 87 model with an 88 GM replacement in it. But we haven't got it running yet. Sorry I can't give you a definative answer.

<font color=blue>azblazor</font color=blue>
<font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>

 

[86blazerk5]

Well, I dont know that they are probablamatic, but you may want to find out a little more, like was the tranny ever rebuilt or replaced in it. Reason being that they all go at some point, and it seems to me that an since its an 86, and we are now aproaching 2002, that it could go at any time if it has not already been redune. My 86 went last April. My friends 87 just went last week..., Of course age is unpredictable, Milage and wear are more important. But just a fair warning, if it is an 86, and it hasnt gone yet, i would be looking for it to go at any time... However, you are only looking at 1500 to replace it stock, or as much as 2500 for a High Performance... so, you can decided if it is worth it to you or not. I would also be on the look out for engine failures, they seem to go 1 or 2 years before the tranny, at least in my and my friends case.
I dont mean to scare you, ask a lot of questions on it, about maintenance...
Ike

Spreading The K5 Gospel!

 

[HarryH3]

'87 was the first major re-design of the 700R4. GM was getting tired of replacing trannies for free, even long after the standard warranty had expired. The first few years of the 700R4, they had about the same reputation for reliability as the infamous 350 diesel made from a gas engine block.

<font color=black>HarryH3 - '75 K5</font color=black>
<a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
It's a great day to be alive...

 

[txbartman]

According to a recent article about rebuilding 700s in eithe 4 Wheeler or 4WOR, the 89, 90, and 91 models of the 700 are the best. They don't distinguish any other year model. As far as failures, Mine is an 85 model attached to a 305 engine. My 700 was rebuilt at about 120,000 miles. I now have somewhere between 150,000 and 170,000. No problems. And I have never had an engine failure.

To check it out, drive it. Check the 1-2 shift. Under throttle, it should be kind of hard, not soft and sluggish. Get it on the highway and try out OD. Just see how it behaves. Check for leaks underneath. After it is warm, check the fluid level. Note the color. You want it close to original red. Check for a tranny cooler as well. If it doesn't have one, that could be a bad sign. If it was ever used for towing there could be problems lingering.

Worst case scenario, you could always replace it with a Raptor 700. They run about $1700 (I believe) and are the best ones I have ever heard about for the money.

Brian
Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!

 

[CaptCrunch]

Yeah 1987 was the first redesign and then there were some other updates done to the 89 and up models., but if the older 700's have been rebuil by anyone with their head on straight, they will already have most of the updates and new designed parts.

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>

 

[71RestoRod]

True, but I think the upgrades are limited with a pre-'85 700-R4, i.e.; smaller input shaft, etc... I think it's best to avoid these...

 

[Calclips]

Thanks to all of you guys, I appreciate it.

 

[mudddog91]

I swapped a 700 r4 into my z71 about 5 years ago.It came out of an 86 blazer and I havent had the first problem with it.I did a few unconventional things to it that I believe have ehlped it live a longer happier life.I run nothing but type F tranny fluid in all my auotmatics,dexron III has additives in it that actually allow the clutch packs and bands to slip during shifts to make for a smoother luxury car type shift whereas typeF doesnt.Only problem with type F is that it doesnt have the same breakdown and anti corrosive properties as DexronIII so you have to change it more often.Type F fluid is sometimes referred to as being the same chemically as b&amp;m;s trick shift tranny fluid.Anyways I also adjusted the TV cable to make it shift a little harder also,This cable adjusts the trannies main line pressure according to throttle position,If its adjusted loose it will shift soft because the pressure will be too low ,as if it were sensing the throttle at idle or low rpm and adjusting it high has the opposite affect!Just wanted to let you know about some of my experiences with the 700 r4.One last thing,If you are somewhat mechanically inclined
you can get a rebuild book from your local autoparts store and a rebuild kit for under 200.00 bones.Its not as difficult as most people believe.