rebuild an auto transmission

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How hard would it be for someone with good mechanical skills but no transmission experience to buy a rebuild kit from RockAuto and rebuild a transmission? I will probably never do it, but have thought about it.
 
With a manual it is not that hard. My trans guy makes it look easy, but he has 40 years of experience.

You would have to take your time and study the diagrams and such.

I've done some manual trans but slushboxes we pull and deliver to the rebuilders.
 
Saw it done many times at the annual Chevy show at the Tonawanda NY Chevy engine plant. Guest from GM Power Train from Ohio does it. Claims hardest part is to remove the tranny and he can do the rebuilt in 10 minutes. Claims no special tools needed but he uses them since he has them. Many clutches and vital that they be put in the right direction.
 
I have rebuilt the 4L60E in 95 K1500 a couple of years ago,
with parts from Makco transmission parts. Just make sure you get an ATSG book for your trans. Some special tools are required, depending on which trans you rebuild. I am a A&P mechanic (aircraft) and machinist by trade, but have been working on cars my whole life. That was my first automatic. Just do lots of research, there is lots of information out there on the more common trans. and it really not that hard.
 
Originally Posted By: Highline9
what trans?


Unsure, the first one of mine that breaks I guess. But maybe I could get a blown transmission from a junkyard and rebuild it and have it sitting as a spare. A blown transmission cannot cost that much. The rebuild kit is less than $200. I am buying a 1999 Dodge Ram diesel and that transmission has 157,000 on it so that might be a candidate. I have two vehicles for myself, so I could do without one for several weeks. I see getting the transmission out and then back in as a larger problem with no lift (yet).
 
Itried to rebuild a th350. After the 3rd time I installed it and had to pull it out it went to a trans shop. There's clutches and discs and orings and bushings etc in there. Oh don't forget pistons and springs in the valvebody.
 
I have rebuilt manual transmissions but never an automatic. The thing that would scare me off the most would be a need for a plethora of special pullers and other tools. For the manuals I have done that was also an issue, but a friend with a lathe and a milling machine was able to make what I needed. It was only a couple of tools though - again my impression is that an automatic would take many more.

The other thing that would worry me is that I would install some thingabob backwards or in the wrong location and then have to tear it all down again to find what I did wrong. Manuals are easier this way as there aren't nearly as many parts. But hey, if you are willing to take that risk and you want to proceed, more power to you. You are more adventurous than me.
 
It depends on the transmission involved, and whether you want to do it right the first time or by trial and error.

Speaking in general, you will need calipers to determine clutch plate thickness, and likely a dial indicator and stand to determine end-play, plus a tool for pulling the pump. You should also have the bushing driver set for your trans ($200-300), and any special tools. If there are any worn bores in the valve body you will need to buy the reamer for each one at approx $200, although you may elect to have this done or buy a rebuilt. You may also need a pressure gauge for setting the throttle cable, assuming there is one.

Handling the transmission is an issue too. Some of them are heavy, and all are bulky. Once you get the torque converter and valve body off you MAY be able to handle it yourself, but don't count on it. You will need a way to have it standing up to work on it.

The simplest trans I have done is the turbo 350, which needed a very simple piston compressor (in addition to the bushing driver set). On the other hand, I just finished an AOD which needed a complete set of Ford AOD-specific tools (which I bought on ebay for $300) plus a couple of others.

If you want to play with a junkyard trans and have lots of free time, you don't have much to lose, but I wouldn't suggest you have high expectations.
 
No one was born knowing how. There's no reason a dedicated focused individual could not do it on his own with a complete manual.

You can rent the trans jack and other tools. Just pulling and reinstalling it will get you a HUGE discount at any good rebuilder's shop.
 
I'll fix a lot of things on a car, and I will replace a transmissiom (We did, with the Jeep), but I would never, ever attempt to rebuild an automatic transmission without being trained to do it. There are a lot more parts in there than in a manual, that all have to go in in the proper order, not to mention all the little things like springs and pistons.

I'll leave Auto trannys to the experts.
 
You'll need lots of room to lay things out.
And a clean area is highly valued.
A trans holder/stand of some sort is more than handy.
I like to lay things out in the order they were taken off/apart.
Makes it easier, esp if you have multiple jobs going on and you go back and forth.
 
not sure what kind of lift you need but you can get a manual with load balancer cheap at harbor freight. I use it about 3x a year with tractor engines. etc. Works decent.

Now removing a diesel transmission sounds like a really bad day.
 
Rebuilding an automatic transmission is not an easy chore, it requires a certain level of skill and some specialty tools. Some of us have more skill and tools than others, so its a tough call. Keep in mind there is no way for the average DIY guy to bench test one either, so it has to go into the car to test. If its screwed up, odds are it has to come out and get torn down all over again.

But they do say nothing ventured, nothing gained. Keep in mind it might take more than one or two tries to get it right. If you have the time, money, tools, are confident in your skills, and have patience go for it. How else can you learn?
 
I've rebuilt some of the old Ford C4, but those are simple in comparison of today's boxes, that I wouldn't touch... Last auto tranny I bought from a online rebuilder and installed it at my buddy's car lot that has a lift... Total cost about $750...

Tom
 
I have done a few. If you have the right manuals and tools, they are not that bad. When I was in school we had a dyno that we could run them on through the gears. The teacher was impressed that the ones I built shifted perfectly and had the right line pressure, I shrugged and said I read the book. It is funny when you install some wrong valves wrong and the thing will shift all weird on the dyno.

Having a large work area that is clean is ideal. Lay parts out like they came out. Don't skimp on the parts. Measure everything. Remember a overhaul kit will not include hard parts so factor that into your estimate as well.
 
Thanks for everyone's replies. I think I would consider the removal and re-install but not the actual rebuild. Not looking at buying specialized tools. But this could justify a lift maybe.

If one gets a reman auto transmission (from Jasper) I assume they do a lot more than just clean it and install a rebuild kit?
 
If I remember correctly, Jasper is pretty good on transmissions. Not just the kit, but inspects for worn hard parts, and even applies cost effective updates, which is where the real value in a rebuilder lies. They probably also have an expensive test rig that assures the valve bodies have no leakage, correct pressures, right shift points, etc, and they almost certainly test the completed trans too.
 
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