So what might I have done wrong that would cause it impossible for me to shift into reverse? No grinding or anything like that - it's as if there is just something blocking the stick from going into the reverse slot. 1st through 5th works great, btw, and I was able to shift into all gears and drive before I took it apart.

Great post - still helping 4 years later! So, I got into the tranny because I thought I needed a new throwout bearing, but discovered that the noise I was hearing was coming from the bearing on the input shaft (the one furthest from the engine). I didn't do a total rebuild - I just got a bearing kit which replaced all of the bearings and the washers. I cleaned everything pretty thoroughly because what had happened with the bad bearing was the plastic cage holding the ball bearings in place broke, and i was chasing its pieces all out of the oil channels and nooks and crannies and such. Any ideas? If you still follow these forums, your help would be most appreciated again!

 

Wow It's been a long time since I've had one of these transmissions open. It sounds like you didn't get the reverse shift fork lined up properly when you dropped the shafts back in. If everything else works fine then it's got to be inside. Unfortunately you're going to have to take it back off and open it up to fix it. Look at the linkage to the reverse fork and make sure it is moving the reverse gear up and down properly.

Sorry you didn't get it on the first try but I'm glad it helped. When you get it back open if you still aren't sure post some pictures and I'll try to help as much as I can. I'm subscribed to this thread so I get e-mails when someone posts. So I should be able to reply within 24h. Good luck!

 

I keep going over it in my head and looking at the pictures trying to figure out what I could have possibly done wrong - I was super-careful (I thought), and really, I just don't see how it could have gone in any way but correctly - I mean...damn! Ah, well...gotta let the knuckles and muscles heal up a bit before I try to crack it open again. It runs great now except for the lack of reverse. Anyway, I'm glad you're still subscribed - I'll definitely let you know what I come up with. I'll take some pics to throw up here, but only if you promise not to hold it against me that I didn't clean the outside of the case and paint it up all purdy like yours =o)

Here's a thought - have you (or anyone here) ever tried taking a tranny apart while it's still in the car? When I was putting it back on (basically bench-pressing it into place while I lay on my back), I got to thinking that i could have first put the bellhousing half on the engine, then put the shafts back in place, then the case, etc. Just a thought =o) - it's heavy when it's in one piece.

 

I think it would be very difficult at best to get apart if at all possible and pretty much impossible to put back together that way. But I'm not exactly an expert so who knows.

You might double check the shift linkage just to be sure before you tear it out. I don't see how that would disable only reverse but stranger things happen. Are you feeling any resistance when you try to shift into reverse?

 

ok i have an s20 trans off of my d15 and pulled it apart replaced the main input shaft bearing and the main shaft top bearing put it all back together and the input shaft cant be turned by hand i have dealt with a lot of rear wheel drive trany's but this is my first front so just wondering if anyone knows a common reason why the trans would lock up after its all back togeather thanks

 

You probably didn't get the shift forks lined up properly when you dropped the shafts back in. Basically the transmission is trying to be in two gears at the same time and that will cause it to lock up. It's really hard to take a picture of but this is the spot you should be looking at.

 

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I've picked this project back up again, and decided to see how well it'd go if I tried taking it apart with it still attached to the car as I suggested. It CAN be done =o) Heh... I still haven't figured out the reverse issue yet, but it's definitely something internal - I've had someone in the car trying to shift into reverse while I watch for binding and such underneath, and I found nothing, so I'm tearing it apart now to see what's up.

Also, I thought I'd add that I've driven it about 4000 miles with no other issues whatsoever - 1-5 work great. Just no parallel parking or parking in spots where I'd have to back out =o)

 

I really just signed up to this site to Thank you for this awesome write-up. I am rebuilding an engine and I'm now going to attempt a rebuild on my transmission (2nd grinding really bad and 3rd grinding sometimes)

Any insight on the 2nd grinding?Is it probably the Syncros? It is an 87 CRX Si D15A3

Also, how did you paint the Transmission? Keep it altogether and cover up the openings? Any tips for that would be awesome!

 

You're welcome! I'm glad to know that this is still helping people years later.

If gears are popping out during a turn or acceleration it's usually a bad bearing giving a shaft too much play. If you're grinding while shifting into gear then the syncros may not be doing their job, but it doesn't necessarily mean they're bad. There needs to be a certain amount of friction between the syncros and the gear in order for them to work right. This can be caused by oil that is actually too slippery such as synthetic or possibly even SJ(common) motor oil. This is why the owners manual specifies SF/SG motor oil. It isn't quiet as slippery as SJ but still slippery enough for the bearings and other parts to work properly. If the transmission is still in the car you might try changing the oil for SG grade 10w30. You can usually find SF/SG labeled as being for older cars or for motorcycles. Or a lot of people have had very good luck with Penzoil Syncromesh usually available at autozone and other stores. If you already have the transmission out or the oil change doesn't work you'll have to check the syncros and gears. If the teeth on the syncros are sharp then it's the interface between the syncro and gear. When you take it apart you'll notice there is a part of the gear that the syncro slides over and it's probably pretty shiny. That's the spot that needs friction. Over the years it's possible to have sort of polished it through normal wear. My friend had the same problem I just rubbed some of the shiny off with some sandpaper and put the original syncro back(after a thorough cleaning of course). Everything worked fine after that.

Hopefully this will help give you an idea of what you're looking for.

As for the paint you pretty much guessed it. I cleaned it all with brake cleaner and a wire brush. Then plugged the holes and sprayed it with high temp engine enamel. I did it while they were apart and just laid them on a cardboard box while painting. You can paint while it's together, as long as you get a bunch of paint inside it should be fine.

 

Hi fathergoat, Thank you for your great DIY!
I have a problem with not being able to shift into gears by hand (I rebuilt the tranny & have it out of the car at the moment). I can shift into gears when I have the interlock guide bolt loosened, but as soon as I tighten it, I can't shift into any gear. Is this normal? Thanks!