Tranny Problems...

4th Gen Prelude SI... H23

I'm grinding third and fourth gears while shifting at 4 grand and above, and sometimes lower. I'm pretty sure it's a synchro problem, but I'm not an expert. Will I have to replace the tranny? Rebuild it? Any idea of how much a tranny would cost for an H23? I have about 900 dollars and if I'm replacing the tranny, I wan't to do a clutch also. I was thinking stage 2 would be appropriate. What's the best clutch out there? Should I go for an LSD too? I can take out a loan...

Thanks for the help..

Dude, check your timing before you go and rebuild...Thats too much money for what sounds like you just have a heavy foot and an old grandma transmission.

Unless you think you can get an honest quote from your mechanic, of course....;)

I'm assuming you mean shift timing? I can drive. I'm pretty sure it's the synchro, but I'd still like some prices and maybe some resources on where to even get a good clutch and LSD. For the hell of it, I'd also like to know where to buy a new tranny just in case. Any websites out there? Thanks for the help.. :help:

Haha, I never doubted your ability to drive, I meant synchro times, just came out wrong...sorry

Anyway, I am not sure about websites that tell you about repair quotes, unless you are talkin performance parts, then you could check out summit racing or something to that effect.
Sorry I can't be more help

No worries. Thanks for trying as a matter of fact. That's more than I can say for most... I was actually talkin performance parts. The car has about 165k on it, so I'm about to just start replacing things. Might as well. Any other general websites for Honda parts are greatly appreciated.

To follow up on this post, I talked to the local tech guy at my local dealership and he said that I might have sprung a leak somewhere so my tranny coolant is leaking out and my synchros are basically welded to my gears because of the heat. This kind of sounds like bullshit to me, but I don't know much about transmissions and synchros. To replace the clutch and tranny it would cost me about 12 - 1400 dollars. Seems like a bit overpriced also, but it comes with warranty. I was thinking about doing it myself. I am relatively automotively inclined, my dad is a mechanic, but he mostly works on old vehicles. Think I can take on a project of this caliber? I have a full shop, and a 4 point car lift. Thanks for the information. I'd still also like to know if there are any good websites out there?

There is no coolant in your Prelude gear box. If there was it would have seized up a long time ago.

What it does have however is Gear box Oil.
If there was a leak and the oil level was low then this would cause premature wear on the bearings and synchros which would make it grind between shifts.
However there would also be lots of oil covering the underside of the car, and large patch where you park it.
But generaly gearboxs don't leak enough for it ever to be a problem, and when they do it becomes a problem very quickly, and a bearing will fail long before a synchro will.
If your dads a mechanic he should know this, and be able to tell you.


That said Honda have not developed thier g/box's much beyond the orginal 4sp in the first generation Civic, and all the manaul boxs whether it be in an Integra or Civic, or Prelude or Accord all share a common design.
Its one that is simple, very efficant (honda's have one of the lowest driveline power loss %'s of any manufactor) light weight and quite strong, but prone to wearing synchros.
Your father might actualy be surprised at how simple it is, and if hes worked on any G/box in the past then he will have no trouble handling a Honda one.
Infact they are much simpler than many of the old Britsh and American g/boxs from the 60s and 70s that Iv seen apart, and worked on.



Removing the g/box and cracking it open is quite an easy task for someone with the right tools, a few days to spare, and a good shop manaul.

Replacing the synchros then only requires a strong press, and some care. And once you get into it is actualy amasingly simple. However once you've got the box out it is almost just as easy to get a specialist g/box shop to do the work, or even take them the gear shafts, and let them seperate them and replace the synchros.
Im unsure of a true price in US $, but with a rough exchange expect to pay from US$1500 for all the work done, including g/box removal, to prehaps US$500 if you take it apart.
Parts might be say US$200 all up if you do it all yourself.


Replacing your box with another is an option, and its certianly the cheapest. Do it yourself one week end and you only have to pay for the box. However what are the chances its going to do exactly the same thing in 6mnths time?
And 12 - 1400 dollars is way to much just to replace the clutch and fit a 2nd hand g/box.

And LSD is only really a good idea if you are currently haveing problems with excess wheel spin on a regular basis, or if you plan on racing the car seriously in the furture. If not then its a lot of money that could be better used else where.

Good stuff, moppie...i'm gonna save that post.
thanks:)

Would the oil from the gearbox be a similar color to standard motor oil? I'll check to see if I can see any under the car also. My dad isn't a professional mechanic, he's just built old street rods, and now is working primarily with older british cars (it's nice to have a choice of 5 jaguars when going out on a date).

Can I remove the tranny without having to pull the engine? Are there any other things in the way? Basically, I'd just like to do a swap. I have about 900 dollars saved up, and while I'm under there, I wouldn't mind replacing the clutch also.

My reason for replacing the clutch is because I had a chatter as I took off at lower RPMs through first and second after this problem developed, and I just wouldn't mind doing it anyway.

I believe you are right about it based on what you have said in the post above and I sincerely thank you for your information.

BTW, the guy I talked to said synchros can be about $60 a piece, I think it was.