alright so I rebuilt a transmission, case is an S80 from a 95 Integra LS. 3.07 1st with 2-3-4 and both shafts from a transmission marked as "92-95 jdm b16" and the original LS 5th. Using the LS differential with the 4.4 final drive. most of the other trans parts were all the ones originally from the LS with the exception of maybe the 3-4 shift fork. All bearings, seals, syncros, and syncro springs were replaced with parts from the B16 syncrotech rebuild kit.

My problem is a 5th gear grind unless I rev match and double clutch. Everything else is absolutely perfect, shifts easy and smooth, no noises, oil was changed once after 120kms were put on. I put Honda MTF in both times.

My question is related to the 5th gear grind. Should I have reused the original 5th gear syncro from the LS? Or did I **** something else up on the rebuild. The tranny always goes into gear no problem but there is a loud and strange grind sound when going into 5th like mentioned however it still feels perfect going into gear. I only have 200 kms on the transmission so far and I dont really mind having to double clutch and I really dont want to pull the transmission apart.

If the problem is from the wrong syncro then i will probably continue to use it as it is however if there is a possibility that something else is messed up I will pull the trans.

The rebuild went together really smooth except i noticed that even with the Countershaft nut torqued and re torqued there was slight play in the 1st gear assembly (approx .010" play) could this have anything to do with it?

Thanks in advance to anyone who replies.

 

All the B series hydro transmissions use the same 5th synchro and sleeve. You may have something assembled incorrectly. I have seen many burned 5th synchros due to the stopper plate not being aligned properly or a hub installed upside down. If 5th shifted okay before the build, I would take it apart for reinspection. It is possible that you may have just reused a worn synchro and sleeve from the JDM unit but in either case you will probably need a sleeve set.

The gear clearance for 1st gear on the countershaft is adjusted by the thickness of the washer under the gear. You want some slight up and down play for each of the gears that have synchros on them. I don't think this is causing your 5th grind.

 

I didn't think this had anything to do with the grind i just mentioned it in hopes that someone good would say something good to ease my mind, which happened


I was pretty careful with the stopper plate im pretty sure I got that right.... If you say installing the hub upside down can cause this problem though then my first guess is I did just that, because i know i used the new synchro and the sleeve was very good i was very meticulous with cleaning and inspecting everything before it went together. Other than this possible error I made. I really dont want to have to pull everything apart again all though I suppose the practice would teach me a lesson. Lol, there aren't enough hours in a day to make stupid mistakes like this

edit: Ok so say that I decide to pulll this sucker out and i pull my main shaft out, how do I tell which is the right way for the hub to sit. What if thats not the cause of the problem, where do I go from there?

 

bump.

the syncro seems to work fine when going from lower rpm than required but when coming from above, like quick from forth it still grinds however not as bad as it used to.

 

alright so, I finally took everything apart. I dont know how its even possible to install a hub upside down (the height would be way too high) or to misalign the stopper plate.
I flipped the sleeve around 180 since it had some little tiny notches on the insde that were facing the reverse side, so when i reassembled it the notches were facing 5th gear. I figured this had to be the problem. Put everything back together and for the first couple of days it shifted perfect but then all of a sudden I got the grind back and now it is exactly the same as before. When I took it apart I noticed that everything looked like new still and the inside of the 5th syncro looked like it hadn't been pushed against the gear cone at all. Didn't check the other gears so im not sure if that was relevant. The trans has about 5000 kms on it about 4000 of which are all highway (took a big road trip).

any ideas? if there isn't anything solid to go on ill probably be leaving it for the rest of the year. my only guess is something silly like mainshaft play or something but there doesnt seem to be any that I can notice. could it possibly be shift linkage? The other gears are all perfect, and this one feels totally fine if I double clutch it like before.

thanks in advance.

 

synchros+hub+sliding collar replacement is suggested from me

 

nope its gone. slider was just upside down and i guess the syncro needed time to break in against the gear or something

 

ya the slider(s) are known to trick ppl including me lol. i installed one upside down once and had ALOT of play. but thanks to me having that itchy feeling something was wrong i took it back apart and fixed it