Tranny Rebuild

[CHawk]

Hello all.  I'm a new guy here so let me first say, this is an excellent site!  I've already learned tons of stuff!

My Truck: 1985 K10 Silverado SWB, 305 (converting to 350) 700r4 tranny (dead in the water). I bought this truck in '93.  I had the tranny rebuilt by AAMCO in '94 not long after I bought it; never was happy with it after that, felt kinda mushy on the shifts, didn't like the shift points, etc.  It's been sitting a few years now due to engine dying.  I've got a 350 lined up to drop in it (not 100% sure what it's out of; a friend built it to drop into a Jeep but never did).

My Problem: Before I dropped a cylinder in the 305, overdrive quit, meaning it would no longer shift above 3rd.  It would also shift directly from 1st to 3rd, skipping 2nd.  I never investigated the problem with the tranny because the engine quit shortly there after.  My question is, is a 700R4 from an '85 truck worth rebuilding, especially since it's been rebuilt once?  I've heard and read that an '87-newer core would be a better choice to rebuild and that I should make sure it's from a 4WD truck, not a 2WD or an Astro.  I've messed with everything else on this truck and my subsequent vehicles but never the tranny; they've always scared me.  But, since this thing is sitting in the driveway now anyway, I'm thinking of buying a book and tackling the rebuild myself in my garage.  I'm not on a time table as I don't drive the truck now anyway and figure I could take my time.

Questions: Can a "first timer" with other mechanical experience tackle a rebuild like this or should it be done by a pro?  Should I rebuild my '85 tranny or look for a newer one?  Does it really make a difference what vehicle it comes from?

Thanks a lot for any info you may be able to provide!

[Blazin]

Welcome from New Hampshire.
 The difference between the 4x4 and 2x transmissions is the torque converter cover is cast aluminum, and is a structural part of the case. The 2x cover is stamped sheet metal.
 I am a body man with plenty of wrench turning ability. My best friend rebuilds transmissions. I have watched him countless times and even helped in the process. I could probably do a rebuild but I would never feel comfortable with the trans after. I would always be wondering if it was right etc. It takes a few specialty tools. The bench and area have to be just short of sterile, you do not want any dirt in the trans.

[CHawk]

Thanks for the input Blazin!

[VileZambonie]

I've had 18 year olds that have never taken apart a trans in their life pull them out of Toyota mini vans and tear them down to the differential and do a complete overhaul. - Granted they had my guidance but if you have a clean work area, and the manual you can do it. You will need a piston compressor which you will have to buy and a lip seal installer which you can easily make with a piece of 3/16" brake line and a piece of mig wire. Make a loop and crush it inside the brake line in your vice and voila lip seal installer. The 700R4 is an easy challenge but you need that book = most critical tool. Where are you from?

[Blazin]

My buddy tests all his clerances with a fealer gauge and air presure. I forgot, yes you need a good book. He gets all his parts from Trans Star. He gets his from Londonderry N.H. but I am pretty sure they have wharehouses all around the country.

[CHawk]

Thanks for the advice guys!

I'm in Colorado Springs.  Bought this truck in '93 in Oregon when I lived out there...can't believe it's been that long!  I think I'm the third owner (if carfax, etc) are correct.  It was originally sold in Florida as a tow vehicle; it still has the trailer plug on the wheel well and the holes where the fifth wheel was mounted.  For the life of me, I can't figure out why someone would have purchased a half ton with a 305 to pull a fifth wheel!

I'm thinking worst case I'll tear this tranny apart...worst case, it doesn't work and I'll have to get another one, which is what I was going to do anyway!  Have you guys heard the '87-newer advice or is that hype?  If I buy a quality rebuild kit will it bring it all up to spec anyway?  I'm planning on using this to tow a light duty (pop-up) camper so I want to make sure it's going to be okay.

Thanks again for everything guys!  I've got a friend with a '94 Impalla SS and he's always talking about his forum....never understood his excitement...until now!

Chris

[VileZambonie]

They added auxiliary valve body, beefier pressure plates and a few other minor changes over the years. When you overhauil your trans you will perform all of these upgrades (minus the auxialiary valve body) anyway. You will modify the PR valve and TV boost valve in the pump. You will enlarge one passage in the pump. The servo should be updated, make sure if your clearances are low which they will be in a few of your clutch packs get a thicker pressure plate. They have different varieties available. Get some trans assembly lube or vaseline for assembly lube and holding parts in place. If you search through some of the older posts you'll see a similar post with more details on a few of those special tools you'll need. Good luck...Oh I asked where you lived because if you were closer by I'd give you a hand.

[CHawk]

'preciate it man!  I'll let you know how it goes.  Probably be a week or two before I even pull it out; I've got to get the garage cleaned up and organized before I tackle anything else!