Pictures and Tips From My 5 Speed Input Shaft Bearing Replacement

[Aaron Cake]

This past weekend I completed some much needed maintenance and repairs on my 2000 Insight. Among the repairs was the replacement of the notorious input shaft bearing (ISB). My ISB had been in a state of failure for the past few months, growing quite loud this spring to the point where the first three gears sounded like they were crushing rocks. It was not long before the bearing was about to get very quiet (you start to worry when a known noisy bearing suddenly becomes quiet) and leave me at the side of the road. So the first weekend in October, the car was pulled into my shop (as soon as I cleared some room) and went under the knife.

I didn't really intend to take pictures for a writeup, but after I reviewed the reference pictures I took during the process, I figured that they might benefit others. Along the way I found a few things out that might help others in their first transmission rebuild. This was actually my first time disassembling a transmission with the aim to actually put it back together, and while not technically a full rebuild, I'm no longer worried for the inevitable time when I blow through another transmission in the RX-7. At any rate, I will now share my process. Typically I'd have better pictures than this but at the time I just needed them for reference so I grabbed my Blackberry 9530, the closest camera I had nearby. So they're not the greatest pictures, but will do the job.

Enough rambling, let's get to it.

Transmission removal is straightforward and the steps in the factory service manual are logical. With two exceptions, however:

1. The FSM instructs you to remove the lower ball joint bolt so that the hub can swing out, thus allowing clearance for the axles to be removed. I took one look at the limited access to that bolt and the necessity for a special tool and said to myself "Screw this". Instead, I removed the two large bolts that hold the strut to the hub. This allowed the top of the hub to swing down on the ball joint pivot, accomplishing the same thing. The axles were easily removed by swinging them a bit to the side once disengaged from the spindle. This is also a good time to check your sway bar end links, because I guarantee you will find them worn out. Both mine were as loose as a $5 hook...well, pretty loose.

2. The FSM wants you to remove the rear engine mount in the middle of the process, before removing the axles and a bunch of other stuff. This made very little sense to me so I skipped that instruction and left all the engine mounts on until the very end. The with a jack under the transmission and one under the oil pan (with a block of wood to spread the load) I removed the mounts. It's a bit of a pain to access the 14MM bolts holding the rear mount to the transmission so I used a box end wrench and hit it with a hammer to shock them loose. I removed that mount as one piece but removing all the 14MM bolts and the two large 17MM bolts that hold the rear portion to the body. No need to remove the long bolt holding them together. Now is a good time to replace your mounts so check them. Odds are the rear one is bad.

Removing the transmission from the engine is pretty straightforward but often they are stuck. You can carefully pry alternately side to side to loosen it up. Use a jack to support it, don't let it dangle.

With the transmission out and on the bench, I followed the FSM instructions to disassemble it but hit a snag when removing the case. The instructions are a bit unclear in the fact that you need to expand the large snap right and lift off the case at the same time. This is really a two person job. I improvised by loosening up the case by prying a bit on the boss near the starter hole (pry against the boss, NOT the machined surface of the case halves) to break the seal. Then, I used a pair of snap ring pliers held open by duct tape, tapped the case a bit with a hammer, and was able to lift it off.



It may take some effort to separate the halves because the sealant will glue them together and the dowel pins will be stuck. Light tapping on each side with a plastic hammer was what gone mine apart. If you have to tap, be very careful not to snap off any of the casting. Some steady prying while tapping helps as well, but do not pry against the machined surface.

Once the transmission was split, I was able to immediately see some of the remains of my ISB. Evidence of self-machining is NOT what you want to see in a transmission! This all ended up near the reversing gear. Notice that gear has no bearing, only a bronze bushing. I'll remember that next time I hammer it in reverse. I hear some new car transmissions use plastic reversing gears.

[Aaron Cake]

Here's a full view of the gearset with the case removed. This stuff looks so tiny, compared to the RX-7 transmissions I am used to taking apart. That plastic piece is an oil duct that is supposed to be in the other side of the case. It's just held in via friction so probably fell out as I was separating the case. There are remains of ISB everywhere...




This closeup shows the reverse gear selector and how it is arranged.



A view of the shift forks and reverse lockout. The FSM doesn't specify, but this is the neutral position and should be how everything is installed again. Otherwise I suspect it would be hard to get the selector assembly back in.

[Aaron Cake]

With the transmission fully apart, you can see the damaged ISB. Look closely at about the 7 o'clock position. The carrier is broken and the balls have shifted around. Shifty balls can be quite annoying at times. The surface of the races and balls have been chewed to shreds. It took some tapping with a plastic hammer to dislodge the main shaft from the ISB, probably due to heat damage from the failed bearing.



This view of the bearing is lit a bit better and you can see it's not happy. Before disassembly, the input shaft had about 3MM of play in any direction. It must have been supported only by the pilot bearing at this point. Removal of the ISB was pretty easy. A piece of pipe stuck down the bore from the other side and a swift hit with a 2 pound persuasion hammer popped it right out. When spun on my fingers, it sang loud and clear! The seal was removed very easily by prying it out with a screw driver. It sucks, in my opinion, to design a transmission where the input shaft seal can only be replaced via complete disassembly.



Much of the metal from the self-machining of the ISB ended up on the debris magnet. It certainly grew some fur.



The FSM warns against resurfacing the flywheel, and I have no idea why. The local CarQuest machine shop did the job in about 12 hours for less than half the cost of a new flywheel. They machined both the friction surface and the stepped area to match. The guy behind the counter couldn't guess what the flywheel was for.

[Aaron Cake]

All the parts went for a bath in my parts washer, filled with "Dunk" degreaser (smells like it is kerosene based). The case halves were then scrubbed with Super Clean and water, as were the shift forks and other linkages. The differential and shafts were rinsed with brake cleaner after the parts washer to avoid causing rust in the nooks and crannies. All parts were blown dry with compressed air with special care taken not to spin the bearings. The only part waiting to be cleaned in this (sideways) picture is the main shaft.



Driving in the new ISB was easy, after the new seal was installed, of course. The outside was lubricated with Royal Purple Max Tuff assembly lube, as was the transmission case. Then it was lined up by hand and tapped into place with the aid of a large socket and hammer. I then spread some lube on the ol' balls...of the bearing...to assure it wouldn't eat itself during the first startup. At the same time the seal got a good splash of lube even though it came pre-slippery.



Assembly really is reverse of removal. Magnet in first, differential next, then shafts and forks go in as an assembly. Of course I replaced both axle seals before I started putting things back together. Everything was made slippery by assembly lube prior to installation and I made sure to let the lube seep into the differential bearings before it was placed into the case. Also the spider gears got a good helping of the slippery as did the shift forks, bearings on the shafts, syncros, gears, and, well, everything. Better to over lubricate than under....and that's what she said.

This is only a job for one person if you have three hands. It really takes two people to line everything up and drop it into place. Tape the splines of the input shaft so it doesn't damage that new seal.

[Aaron Cake]

Here's where I deviated from the FSM again. When installing the linkages, install the reversing gear after the reverse selector is installed. This sounds like a "well, duh" moment, but the FSM tells you to install the gear first. With the gear in place, the selector can't be installed. I'm still amazed that reverse is selected by basically banging a gear into place between the main and counter shaft. No synco, no bearing, and the selector rides right against the machined surface of the gear. No wonder reverse is a bit hard to find in every Insight I've driven.

Don't forget to line those shift linkages up in neutral, otherwise you'll be doing it later via a screwdriver through the selector hole. Lube the tops and bottoms of the shift fork shafts as well.



As splitting the case was a bit funky, so is reinstalling it. I didn't do a dry run and because of that, my sealant went off in the time I was fiddling with the case. I had a lot of fun scraping it back off and recleaning the mating surfaces. Speaking of which, clean the living hell out of them. I used a brake cleaner soaked rag and compressed air to clean the mating surfaces and made three passes on each side of the case. It is vital for any kind of sealant that the mating surfaces be very, very clean. Hell, when is there ever a time when any "mating surface" is preferred dirty?!

Now, the trick. I had a problem getting the snap ring to seat in the groove on the counter shaft bearing. It would hang up and not allow the case to close. After the first failed attempt, I made a dry run and figured it out. The case was sort of hanging up, so I slid it over the shafts and down just to the point where the snap ring rested on the top of the bearing. Then I expanded the ring, which allowed the housing to drop down just a little so that the ring was about 2MM above the groove and held open by the bearing itself. Finally, I pried up just a little on the counter shaft through the shift selector hole to push the shaft up into the housing. There was just enough play in the shaft so that it moved up enough to push the snap ring into the well lubricated groove with a satisfying "click". The the housing slide down on the dowels and mated with its other half. Of course then I had to remove the snap ring and case again to apply sealant, and repeat the procedure for the final assembly. The sealant I used was Permatex Ultra Grey as recommended by my local Honda dealer (Westgate Honda). It was spread in about a 1/8" bead along the entire mating surface, circling both the bolt and dowel holes. Trust me, you want to get this step right.



The bolts were then torqued in 3 steps to 20 FT-LBs. Finally, the shift selector was installed as well as all the sensors, check balls and switches. Don't forget those little spring loaded check balls; they are what holds the transmission in the selected gear.



And that was basically it. I let the sealants dry for a day and then went about reinstalling the transmission. At the same time I replaced the clutch, pilot bearing and throwout bearing. Getting the transmission to line up with the engine was a bit of a pain, but then it always is. Luckily it is small enough that it can be man-handled from the top. The trick is keeping the flanges of the transmission and engine perfectly parallel otherwise the input shaft won't be able to engage the clutch splines or pilot bearing. Fun fact, the clutch splines and pilot diameter are exactly the same as those on the Mazda M type transmission as used on all '78 - '92 NA RX-7s.

As during removal, I installed the engine mounts first once the transmission was mated to the engine. I installed several of the transmission bolts snugly, then installed the mounts loosely. Once the mounts were supporting the weight of the transmission I installed the remaining transmission bolts and torqued them to spec. Then the mounts were torqued. Anti-seize was used on every fastener during the entire job except those internal to the transmission.

While the car was up in the air I also replaced the brakes and changed all fluids.

Overall I'd say the job was pretty straightforward other than those few bits I mentioned. It took two weekends and a weeks worth of evenings because I was kind of working at half capacity, being quite sick at the time. I have a considerable amount of mechanical experience in everything from engine building to sheet metal, as well as some fairly advanced fabrication, tuning, and basically everything else (check the links in my signature if you are interested) to do with cars but as I mention, this was my first transmission rebuild. I think it's safe to say that anyone with the space, a bit of experience and a good set of tools (no special tools are required) could do this job. But count on the car being down for two weeks if this is your first major job.

[Eli]

Excellent post! Thanks.

How many miles are on your transmission? I assume you don't have grindy downshifts? Did you think about replacing the synchros(gearsets) as well, while you had it apart?

[chisight]

Aaron, Great write-up, thank you.

I have a noob question on "neutral", I can see the two mouths of the shift forks are even with each other, but is this all it takes to have them in neutral, or is there some other reference they need to be aligned to?

I see the "TMB" stamped on the old inner race, I had hoped that the "TMB" on the new part was the reason for the part number change, TMB is NTN's premium line but it looks like we've always had a premium bearing.

Is it reasonable to lubricate by simply working some synthetic moly grease into the bearings without messing with assembly lube?

Is there a trick to getting the snap ring back in, or do you just have to play with it until you get it seated?

I've read something about a shift lock bolt on Civic/CRX transmissions that has to be done perfectly or it breaks something on the forks. Do we have a problem like that? Does the reverse lock cam have to be in a particular position before assembly?

Once the damper pinch bolts are removed to get the drive shafts out, does the front end need to be aligned?

Is the "sway bar end links" what Honda calls 51320/1-S3Y-003 "LINK, R/L. FR. STABILIZER", or are you just talking about replacing 51306-S3Y-003 "BUSH, STABILIZER HOLDER"? If it really is the stabilizer link, what do I look for to know it's bad? oval bolt holes?

Thanks!

Chisight

[talonmike]

Wow

Very useful post. Thank you very much.

[retepsnikrep]

Originally Posted by Aaron Cake

Shifty balls can be quite annoying at times.

I can concur with that

Nice pics and write up thanks for making the effort.

[Aaron Cake]

Originally Posted by Eli

Excellent post! Thanks.
How many miles are on your transmission? I assume you don't have grindy downshifts? Did you think about replacing the synchros(gearsets) as well, while you had it apart?

The noise started at about 260,000KM, and I finished this repair at about 275,00KM. My transmission still shifts smoothly with no syncro problems so I didn't put much thought into it. Actually, the syncros had very little wear and looked quite new. I always rev match/heel-toe every downshift so that probably has a lot to do with it.

Originally Posted by chisight

I have a noob question on "neutral", I can see the two mouths of the shift forks are even with each other, but is this all it takes to have them in neutral, or is there some other reference they need to be aligned to?

In the neutral position, the notches on the shift forks that engage the selector are all lined up in the middle of their travel. That way the selector just slides right in. It's not a big deal if you don't line it up during assembly because you can also reach it via a screw driver while installing the selector, but it would be easier to line up with the case off.

I see the "TMB" stamped on the old inner race, I had hoped that the "TMB" on the new part was the reason for the part number change, TMB is NTN's premium line but it looks like we've always had a premium bearing.

The new bearing I received had a totally different part number on the inner race than the old one. The new one is "TMB /26V150" while the old one is seen in the pictures. I don't know the difference, but there must be something otherwise the part numbers would be the same. Maybe they switched hardness on the new bearings since they had so many failures of the old?

Is it reasonable to lubricate by simply working some synthetic moly grease into the bearings without messing with assembly lube?

I don't see why not, but assembly lube is purpose made for assembling mechanical fixtures. It tends to cling very well, doesn't go away after sitting but does wash away once the proper lubricants start to circulate. I guess moly grease would do the job but probably end up clumping up in the bottom of the case after it washes out of the bearings. If you don't have any assembly lube, a bit of Honda MTF would be my next choice.

Is there a trick to getting the snap ring back in, or do you just have to play with it until you get it seated?

I didn't remove my snap ring from the housing because I didn't see the need. But a set of snap ring pliers does the job of both removal and installation. As mentioned I pushed up on the counter shaft to help seat the snap ring once I got it halfway installed. Without doing that, I couldn't get the case to fall down enough to allow the ring back into position.

I've read something about a shift lock bolt on Civic/CRX transmissions that has to be done perfectly or it breaks something on the forks. Do we have a problem like that? Does the reverse lock cam have to be in a particular position before assembly?

The reverse lock is spring loaded so it just kind of sits there, according to the manual. I didn't do anything special with it and everything went together fine.

Once the damper pinch bolts are removed to get the drive shafts out, does the front end need to be aligned?

Nope. The bolts have shoulders which put the spindle back in the same position it was removed from. However I should mention that my shock bolts were quite a task to get loosened. It took a considerable amount of penetrating oil (over night soaking) and a 500 FT-LBs impact wrench to break them free. The nuts didn't survive so I purchased new ones at the fastener store and thoroughly cleaned the threads of the bolts with a wire wheel. Those are some of the few non-coated fasteners on the car, so rust had locked everything together. I replaced the nuts with plated parts and the bolts got a generous helping of anti-seize.

Is the "sway bar end links" what Honda calls 51320/1-S3Y-003 "LINK, R/L. FR. STABILIZER", or are you just talking about replacing 51306-S3Y-003 "BUSH, STABILIZER HOLDER"? If it really is the stabilizer link, what do I look for to know it's bad? oval bolt holes?

The end links are parts 7 and 8 in this diagram:

Honda Automotive Parts

They have a ball joint at each end with a plastic bushing. In my case the plastic bushing was totalled on the driver side and the ball was about to pop out. On the passenger side, it was merely loose with a fair amount of play. If you have to remove these, it's likely you'll be grinding the nuts off because of corrosion and the fact that the ball joint will just spin as the nut is loosened. The allen head on the bolt to hold it from rotating will almost certainly strip out.