Thoughts on DIY manual transmission rebuild?
 

I'm sure someone has asked about this before, but I'd like some fresh perspectives on the matter.

Do you think rebuilding a manual transmission is doable by a relatively amateur mechanic? I just successfully rebuilt my first engine ever (not a rotary, replaced/machined all internals but the rods), and I feel like taking on my FD's tranny next. It's grinding regularly when shifting into 3rd and 5th, except when driving it very calmly.

I have the FSM, and I would be either purchasing or borrowing any specialty tools involved. I'm also very capable of following instructions meticulously.

So, what does everyone think? Should I go for it, or would you recommend against it? The transmission has just always struck me as something I'd never be able to take apart and put back together correctly, but my recent success with the engine rebuild seems to have boosted my confidence a bit.

I appreciate any thoughts on this!

- Jim

If that's true, and your tranmission needs an over-haul, sounds like a great way to save yourself alot of money.
This might also help the decision process..... http://www.davidgeesaman.com/

Take a pic, take a part off, take another pic, take a part off, This process should help to make sure you don't mess anything up.

I've pulled them apart (mostly to inspect broken ones) but never fully put one back together. My advice is to get another a second one to work on. You'll most likely break something as you're learning, and you may have to combine some parts between the two.

You should be able to get a rebuild kit from a transmission shop. They are basically beefed up versions of Mazda-built Explorer/Ranger transmissions.

I wouldn't go into it thinking that you're going to save money. You probably won't, not the first time you do it. You'll end up acquiring tools and possibly obscure parts. A transmission rebuild isn't that expensive if you drop it off somewhere. Think of this as a learning experience more than anything else, which is partly why I suggest you acquire a second transmission to practice on.

It's hard to justify rebuilding a trans when you can buy a used JDM trans for SO cheap - typically about $350-400. The only thing I'd do with a JDM trans is bust it open to check the 5th gear synchro, if that's good pop it in and rock and roll.

Dale

you'll need a specialty puller to remove the rear main bearing at least, it is a real bitch to get off sometimes as it tends to fuse itself to the mainshaft.

disassembling/rebuilding a transmission i would rate more difficult than an engine rebuild. not simply because you can do an engine rebuild with very basic tools but because there is a learning curve to these transmissions that is steeper than the engine. don't be surprised if you damage something on your first attempt, so a spare is a good idea.

Agreeing with Dale here.

If you're just bored and want to learn, then have fun. There are a lot of specialty tools involved with a rebuild.

One more vote with Dale - unless you're putting together special parts (cryo treated or REM polished or a Greddy gearset) it's just simpler to get a good low mileage used transmission. When rebuilding, replacing worn parts gets expensive fast.

Fortunately, if it shifts ok but makes a little noise that's usually the front main bearing. You don't need to pull it all apart to replace that bearing.

If you can do basic machining, instead of trying to find the specialised long legged type, a garden variety puller can be used to remove the bearing with some ht threaded rod and a bit of nous.

http://img827.imageshack.us/img827/9396/004hqp.th.jpg

Betting the needle roller between input and mainshaft is sad if 3rd is being difficult.

Bearings alone, at least over here, would run a few times the cost of a second-hand box.

I agree with everyone else: It's not hard to do, but it is a pain in the ass and not worth it, just get a JDM box.

It's not overly complicated, but it is a pain in the ass. I'd do it if you want to learn and don't mind spending time and money to do so. The cheap and easy solution is to buy a used box.

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