My S40 B000 transmission roars and bogs like crazy and I'm going to rebuild it. Should I buy a used S20/40 A000/B000 transmission to interchange parts, and to practice disassembling with? I've never taken apart a transmission and I can't risk screwing up my daily, so I thought of buying some used Civic trans to use practice and use parts from. I'm also going to buy a rebuild kit with synchros & bearings.

I've seen some for $100 OBO with 2nd gear popouts on CL, worth buying?

 

If you're going to spend money on one, then rebuild that and keep the current one as a spare or sell it.

 

Find out what is wrong with the one you have first. I can see buying a known good tranny, even if DX to keep the car on the road while you rebuild the current victim.

 

It's worth buying one if you can get it for under $50. I ended up with quite a few D-series transmissions over the years. Of the ones I bought I never spent more than $40 on one.

If you do buy one to use for parts, make sure it's also an S40, the S20 uses different shift forks and a different 3rd/4th sleeve (which is often bad on the 3rd gear side)

 

Thanks for the advice, but anyways, where the heck do you find a $50 D series transmission? Everything on CL is $100+

 

I used to get a lot of mine from guys that were doing swaps and just wanted to get rid of them. A lot of them were free. Almost all of them had something wrong with them. Either a bad bearing or a worn out sleeve and gears.

 

Finally have the ***** to take this apart S40 A000 transmission. The mainshaft bearing exploded apparently, and the 5th gear synchro hub is f*cked. Are A000's bearing/synchros interchangeable with a B000's?

 

They synchros, sleeves and hubs are all the same. Some of the bearings are the same. The diff bearings, bottom countershaft bearing, and middle countershaft bearing are different. The top mainshaft bearing might have a larger outside diameter on the B000 too, I can't remember. 1st and usually 4th gear are the same (HX IIRC is different, and maybe CX/DX hatch) 5th is also the same. Remember to always replace gears in pairs. Also, remember to use a new input shaft bearing and seal, even if it isn't bad. They fail so often it's just not worth using a used part there.

That mainshaft is destroyed.

That the rest of it apart and see what you've got. I hope you didn't pay much for it, that thing is strictly a parts transmission.

 

holy clogged oil passages and kept driving!

 

I never even noticed that broken 5th gear hub until just now. I can't say I've ever seen that before.

 

I'm about to buy a 80k miles S40 EX transmission from a private seller, how do I know if the inside is good? Is there any way to check, or do I have to split open the case and look? Does turning/moving the mainshaft offer any insights on how good the transmission is?

 

You have to split to learn anything useful. You can grab the input shaft see if it moves. If it does you've got a very bad input shaft bearing, if not it still might be bad. Either way it only tells you you need a $30 ISB and seal.