PDA

View Full Version : Pilot bearing or a new transmission?



Derek
07-23-2009, 12:41 AM
Hey everyone...just got done putting my s13 back together after installing the fuel cell, steel driveshaft, nismo slave, new clutch master and solid rear subframe bushings. The car ran great, except for shifting into 4th. 4th gear grinds pretty bad and then pops out EVERY time on decel. I also noticed that when I started the car I can hear a whining/grinding sound from the transmission until I push in the clutch. I initially assumed that my pilot bearing is out, as I have not replaced it at all (still running the one that came with my motor set :rolleyes:). However, what would be causing the 4th gear popping out? It actually feels like 4th gear wont pop all the way into place, leading me to think its a wrecked synchro or shift fork. Could a worn pilot bearing cause this or do I need to swap the guts of my SOHC ka trans to my sr bellhousing? Does anybody know of a writeup of how to do the bellhousing swap? Any help is greatly appreciated. Thanks. -Derek

Derek
07-23-2009, 06:17 PM
One other thought...I was wondering if this problem had anything to do with the backlash in the transmission set incorrectly. I had my KAAZ 2-way installed by a shop, but the guy there told me after it was done that he hadn't really done anything like it before....probly could have done a better job myself. If the backlash was set so there was excessive backlash, could that make the transmission pop out of gear, given the subframe is now solid and transfers more shock? I noticed that when I decel in any gear the car seems to lerch a little bit....like I can feel the backlash....idk...any thoughts or feedback is appreciated. Thanks. -Derek

djsilver
07-23-2009, 07:15 PM
If it's only noisy with the clutch engaged it's the transmission. If it's only noisy with the clutch disengaged it's the pilot bearing or throwout bearing. As far as popping out of gear, taking out the rubber pieces might put it over the edge if it was close to being shot already. You can download a factory service manual and use those directions. SR and KA transmissions have different ratios but the bell housings will swap.

Derek
07-24-2009, 06:29 AM
Well, I'm gonna swap my KA trans and see what happens (swap bellhousings that is), I think I should also go ahead and put a new pilot bearing in for good measure, since they are relatively cheap. What kind of tool do I need to remove and then install the pilot bearing?

djsilver
07-24-2009, 09:58 AM
It's definitely a good idea to change it and you'll need a pilot bearing puller. You can borrow them from most auto-parts chain stores. The new bearing will be less than $5.

Derek
07-27-2009, 05:24 PM
Well, I pulled apart my KA transmission to swap it into the SR bellhousing, and ended up just pulling the tailshaft off in order to inspect the gears and synchros. Turns out its a good thing I did, because nearly all of the gears are chewed up pretty bad and the bearings on the mainshaft and countershaft are shot. I dont know what I should do now, I can't afford a mazworx kit to swap to a 300zx transmission, so I looked online at rebuild kits and found them to be around $250. Should I throw a rebuild kit in my SR trans (synchros and bearings) or look at a junkyard for a newer KA trans? Let me know what you think. Thanks. -Derek

djsilver
07-28-2009, 10:50 AM
You can probably buy a used KA transmission for the price of a rebuild kit or less. That'll save you the labor for something else and put you back on the road while you save up for your monster transmission setup!

Derek
07-28-2009, 08:15 PM
Well I had my car out today and I seem to have a pretty bad vibration when traveling at high speeds. I got it back on my lift and started checking so see if anything is loose, and it seems like the output shafts on the differential have excessive play, which would cause my clunking noise on decel and accel. The play in the shafts is so bad that you can actually see the shaft move in the pumpkin when you put sideload on it. Does anybody know the procedure for choosing correct shims to fix this? Do I need to replace those bearings also? I have a sneaking suspicion that this was set improperly when the shop put it in, causing my transmission problems as well. It just seems that there is WAY too much backlash and play in that rear end. Any ideas?