Search the Community

Long time member, first time poster... I have a track s13, decent power, after market suspension / brakes / skyline drivetrain behind the transmission. Manual 5 speed SR20 box of some description. Im having some trouble with the trans - it doesnt want to select a gear, then it will, then it wont. If the car is stopped its the same deal, clutch and declutch, try again it'll generally go in. 50% of the time the car wants to creep forward while the transmission in is N. This sounds like a synchro problem. Perhaps its easy to fix, but I know transmissions get really expensive really quickly and I have the skills to remove and replace the box but not to investigate the problem. So I decided to just buy another SR box, swap it in, and if that breaks too then look at an RB25 trans conversion. I got messed around on the first attempt to buy one, then had an option to buy an RB20 box, from an S13. I held back for a while but the seller said it'd fit, and my mates said it'd fit, and the info I could find about it on the net said the belhousings needed to be swapped, but that it'd fit. So I took the plunge. Now I find I had a bum steer and the box most definitely doesnt fit AND the bellhosing length is different between the two boxes, so even if I was to swap the bellhousing and if the parts inside were swappable to make a functional box it'd still end up longer and not fit in my car. The seller looked at the pictures of my box and thought that maybe I already have a RB25 box. Im pretty sure I dont because the box has CB71C on the side which lines up with it being an SR20 box, and it fits the SR20 engine with no adapter plate or visible mods. So. Im currently thinking sell the RB20 box and call it a fail, and buy another SR box. 1) What box is the original one in the pics - SR20? I know there is a stronger triple synchro S14 box - Is it one of those? From the fault description, is it worth opening it or getting a shop to look at the synchros rather than replace? 2) Is there any way the RB20 box could be modified to fit? If it could would it be substantially weaker and a bad idea?