I realize a "simple transmission rebuild" seems like an oxymoron....but just curious if there is a transmission would be good for a first-time rebuilder. From what I understand, manual trans are much simpler that autos, but don't really have a preference. Looking for something to run behind a 327. Thanks!
just built a turbo 350 automatic first time with a book. works fine. Follow instructions. the main thing is how hard is it to take out and put it back in.
I have to agree, a TH350 is pretty easy if you buy a complete overhaul kit and follow the pictures. You will need a large bench and a parts washer. Compressed air will be helpful for checking the valve body. As far as manual trans goes, any three speed GM unit from '55 up is pretty much the same. Since you don't have any experience you won't know a bad synchronizer from just looking at them so replace with any other obviously worn items.
The hardest part of rebuilding a t350 is removing/ installing the low/reverse piston which is the last part in the back of the tranny. It takes a special spring compressor which you can buy or copie another and make your own. A powerglide is easier.
If anybody had the time, id love to see a rebuild with pics. Transmissions always made me nervous but if you can do it at home without too many specialty tools thatd be great.
My first rebuild was a Borg Warner T5 5 spd. I paid $20 for a rebuild video from Bad Shoe Productions, worth every penny. Walked my thru ever step, simple to understand, very clear. It really wasn't that hard. If you have good directions, nothing is that hard. Chris
I rebuilt a 400 in High School....wasn't that difficult. The most important thing is cleanliness. Have to get it really clean and keep it that way as you put it back together. If you start out with a transmission that you know some history on its better for your first one.
My first trans rebuild was a 700r4. Buy the Haynes manual, for GM automatics, it has all the pics and instructions you need. Its not hard, just take your time and clean, clean, clean. Stay away from "green" water based cleaners as they are garbage and caused me more issues then the actual rebuild process.
I've rebuilt probably a couple hundred transmissions. They all have their quirks and inherit design flaws. Best to get a specific trans rebuild manual for the particular trans you're rebuilding that show exploded views and diagrams. You will most likely need special tools to remove and install certain parts of the trans, those can be rented at a NAPA location or CARQUEST. Cleanliness cannot be stressed enough. Dirt and debris is a trans worst nightmare, doesn't take much to cause havoc and stock up on Petroleum jelly cuz' you'll use a lot of it!. I prefer it over the expensive Transgel. Once you get the hang of powerflow and what applies when, you'll have a better understanding. Good luck and take your time.
The Chevrolet aluminum Powerglide is the easiest automatic transmission (transamatic automission for the dyslexics out there). One set up for drag racing only, particularly with a dragster style shortie kit, is even easier. I use the same clutch spring compressor for both reverse and high gear clutches; it's one I made using a steering wheel remover, some all thread, and a few bolts, washers, and nuts. And the Glide came behind 327's starting in 62; the Glide was retired in 73. Now everyone thinks they're made of gold when trying to sell one. Most of the ones I've built I got for free, or never more than 25 dollars. Hardest part is cleaning the grease and grime on the outside, and the varnished ATF from the inside. Get a copy of Carl Munroe's (RIP) book, Powerglide Transmission Handbook-How To Rebuild Or Modify Chevrolet's Powerglide For All Applications, printed by HP Books. You'll learn more about the Powerglide than you ever wanted to know. I am Butch/56sedandelivery.
Any of the older 3-speed (or two) automatics are fairly simple. Automatic kits of soft parts are fairly cheap, the expensive hard parts are usually reusable. Most of the special tools are pretty simple to fake, but a multi-step bushing driver and maybe an adjustable cam bearing driver will do a lot. Most of the rest are all-thread and bits of angle iron. Keeping track of all the bits, including seemingly hundreds of round things that all look the same, is the big issue. My tech on that is simply a good big surface to organize...at least a picnic table of space. Cover it with multiple layers of newspaper, keep discarding layers as you move from filthy junk to ready to assemble. The trans comes apart in a few units, like pump, clutch packs, tail, all separated by various washers. I lay them out in order from front to back of trans in a couple of rows across table, with intervening thrust washers in between the big lumps. Front of each part is to the left or, if it is flat, up. Each lump can then be split up into its components, always laid out by the same rules so I always know order of all the plates and front. As you remove the parts that will be discarded, keep them right beside their old homes because you will have to compare a lot of things like O-rings to choose the right one from a whole bunch. If your cat runs through things and scatters them, the clutch steels are excellent tools for slashing your wrists... Finding the actual problem that stopped a trans is always enlightening...it will generally be one damn worthless o-ring worth 10 cents that took out two gears, but the whole $%$%$##$ trans had to come apart to replace it...
Really good advice here. I would add that understanding how it works is essential to modifying something. Manual gear boxes are easier to see how they work but autos are not really much different. The clutches/bands/mechanical diodes are just used to engage the mechanical gears to give you the ratio for each speed. Assemble the guts of the unit outside the case and stand it up on the bench and spin it to see how it changes ratios (some are easier than others to do this.. might need a buddy to help drive or hold). Also... no matter what unit you do (manual or automatic) make sure the damn thing turns freely by hand before you attempt putting it in a car. If it won't turn smoothly, something is wrong. Endplay checks are also key. Check it before you take anything apart and double check it when you have it back together. It better make sense as to how it relates to your work. Engines are really cool but not worth a damn in a car without a good transmission Ever seen a hot rod on the street without one?
Forgot the valve body...again the main issue is keeping track of the bits, which requires EXTREME care here. There are loose check balls just hiding in little pockets, and about 897 organized valves and pressure regulators, each made up of something like a piston, a spring, and bits created specifically to confuse you! Split the halves with extreme care, and save the gasket to compare because there may be more than one in the kit. Set the thing on corrugated cardboard as a way of setting down tiny parts in ordered groups without having them roll away. Lock the cat in a closet, send the family out to a movie, and be prepared to kill anyone who comes near. You will find lots of things with only microscopic differences, and there are probably not enough pictures on earth to sort the thing out if two pistons roll off together! Treat keeping every group right by its hole and separate from the others as a RELIGIOUS OBSESSION. Trust me on that. Shop manual pictures may not even match what you have, as the factories make minor changes down here for different model cars...this is where and why a turbo 400 for a Cadillac shifts differently than the one for a 427 Chevelle. By the way, this is where you will be changing out tiny parts and perhaps removing some entirely if you are installing a shift kit. Again, be realdamncareful. All cleaning will demand extreme care and doing one thing at a time. Very little in a trans is hard to do but if parts get confused, it is very hard for a non expert to recover. Imagine yourself at the transmission shop, your trans poured into a wheelbarrow, sobbing bitterly as the staff hastens to put out the "Closed" sign and hide in the back room...
I remember rebuilding my first transmission at age 16. It was a TH350 and we had one of those Peterson manuals. Everything was pretty simple, and reassembled easily. Until we found that little curlyque spring on the bench. The book didn't show that. We got to disassemble half of it all over again. Asked around and found out what it did, but still didn't know how it fit in there. Up, down, back, or what? Only so many ways it could go in and we had success on the last try. A GOOD instruction book is worth every penny.
Also a good shift kit, because the better manuals for those do a pretty good job on the valve body. You can't have too many books if you find a stray part... I once found myself short a couple of gears after overhauling a 904 and reinstalling it...I could tell that a certain drum was the problem from the diagnostic chart, but had no clue as to what I had scrod up. I took the thing out and stared at the clutch drum for a long time, then took it apart and stared some more. I finally realized I had put its piston in upside down! There were tiny nubbins on one side that were actually fulcrums (Fulcra??) for a sort of belleville washer spring. I had not even noticed them...but it would not have mattered if I had been successful at keeping all the parts facing in one direction as I suggested above! One damn flop...two days shot to hell, including a lot of time wasted identifying and scrutinizing innocent sections of valve body and the health of various O-rings. One of the real issues on an automatic is that there is no way to see if it works until you have it buttoned into the car. That means that any mistake requires a HUGE amount of work, as nearly nothing can be examined or fixed without total teardown.
As for manual. I learned overhaul 55 to 57 chev manual trans for my friends. Used to keep a couple ready to go in my garage. They are fairly easy. Torqflites are very easy as well. I use an exploded view but after you have done a few it is just a safety measure. Powerglide should be easy too. Haven't done one in maybe 40+ years but as I recall they were not too hard. I always do my own trans for my race cars. don
I worked professionaly as a mechanic for over 20 years, doing mainly transmission and engine overhauls. Automatics scare most people, but with a good manual and clean working place they are not bad. I always enjoyed building automatics
Have a good air compressor and nozzle to test the clutch and band operation. Cleanliness is first and foremost.
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