Hey Guys,
I'm just curious to see if any out there has been ballsy enough to undertake their own transmission rebuild! I eventually want to do an AOD swap on my f-150 but afraid that after I go through all the work to swap the trannys out, I'd end up with a bum trans and stuck on the side of the road. I figured since I'd be taking a gamble with a used tranny anyway I might as well give it a stab. It's just a thought right now but I wanted to see if anyone here has actually done one and how "involved" it really is. I'm not afraid to dig into one I just don't want to waste my time and find out I couldn't do it.

Any input is much appreciated!
Al C.

 

I have done several transmission rebuilds. C-6, 4R100, TH350, AW4(VW), and some others.

2 biggest things to watch in an auto is:

1: Having the right tools. Many of the clutch packs require special tools to take apart and put together. If not done properly, the clutch pack will likely fail. Also, you can't even get the parts out without special pullers and clamps.

2: Clutch pack clearances. There is a very fine line of how much clearance is allowable in the clutch packs and this is where most trans are built wrong. If the pack is too tight, it binds and overheats, and if too loose, it slips and overheats.

And then with the AOD, you also have the cable. That cable controls line pressure in the trans and can easily burn a trans up.

I have bought the tools I needed off Ebay and other places as necessary. With all I spent, I could have taken them to a rebuilder, but then I would not have the satisfaction of doing it myself.

Would I recommend it to a first timer, no.

 

Haha thanks I appreciate your honest input! I think I want the satisfaction of saying "I did it" but you're right on that I could have a shop do the whole job for what the parts and tools will cost. Plus then it's done right...the first time.

How did you check clearances between the clutches/clutch packs? I've been watching some YouTube videos. The auto tranny is just an amazing piece of complicated machinery!

...And that throttle valve cable? Psssssh that doesn't scare me. LOL

 

I'm a full time auto tech and handle all of the transmission rebuilds at our shop. I've been building trannies for about 18 years, everything from the old cast iron two speeds up to the current computer controlled models. They all work on the same basic principles so its not rocket science.

AODs will quickly self destruct without the TV cable attached, and proper adjustment is absolutely critical for longevity on these transmissions. The throttle valve controls the line pressure and shift points based on throttle angle. Don't let that part scare you though, its really not that complicated. AOD pistons can be a little tricky to install in the drums too because of the drum design so I have a set of lip seal protectors at my shop for that particular model. One ingenious little tool that was developed in recent years though is the Lip Wizard:

Lip Wizard


I used to battle stubborn lip seals with a feeler gauge but this simple plastic disc makes installing them a breeze. Its included with all Trans Tec kits.

To check the clutch pack clearances, you'll need feeler gauges. I've found most of the time they are within spec, but I always check them anyway. Changes in clutch pack clearance are usually done through pressure plates or retaining rings of varying thickness, depending on which transmission and drum you are working with. End play is measured with a dial indicator. I always air pressure test the assembled drums too before installing them in the case. Another thing to watch for is the snap ring on the intermediate sprag, they are known for breaking. The aftermarket makes a stronger, spiral ring that solves the problem.

Do your research, maybe buy a DVD on that model before you tear into it and see if its something you feel confident enough to tackle. But don't feel intimidated by it. As long as you keep everything organized and have a basic understanding of how they work you should be able to handle it.

 

I agree with Rowdy. The air test essential. That will save you a lot of transmission sex.

 

Lots of great information gents! Thanks. In the meantime I actually found a well planned set of videos of a gentleman rebuilding an AOD for his crown Vic. Very detailed and covered things especially like the lip seal tool (which he didn't have) but managed to use a soda bottle.

Thanks for the vote of confidence! I'm kinda of intrigued now to rebuild a tranny!