Sunday, July 28, 2013

Minor Details on Transmission Rebuild

I finished up installing the fifth gear and the shift fork for fifth and reverse gear.  I went ahead and temporarily installed the tailshaft, top plate, input bearing retainer, and the shifter to test everything out.  It seemed to not want to shift well into 3rd or 4th at first but after going through the gears a few times it smoothed up. 

With the transmission case and internal gears assembled, I've a few smaller details to finish up. 

The existing speedometer gear on the output shaft is a green, eight tooth gear.  This gear works fine with up to 3.55 rear gears.  A speedometer gear with fewer teeth is needed if you want to use more than a 3.55 rear gear.  I've 3.25 rear gears currently installed but might upgrade after the new transmission is installed so I decided to switch to a six tooth gear.

The M7000A rebuild kit comes with a tailshaft seal but not the bushing.  I ordered the bushing and the speedometer gear from CJ Pony Parts this past Wednesday.  They are often a little slower on shipping but the cost was good.  I don't mind waiting as there are other things I need to finish up and money to save to finish up the project anyway.

I purchased a replacement input bearing retainer which is steel instead of aluminum.  The aluminum piece was held in place with four 8mm bolts (right in picture below).  The new one has beveled bolt holes so it seems like you would need more of a machine screw to hold it in place properly (left in picture below).  The bolts only get torqued to 20 ft/lbs so the machine screws should hold up but I don't really know what I'll do here.

I also need to set the endplay on the input shaft.  When I bolt down the input bearing retainer, it is more difficult to turn the input shaft.  I don't have any shims behind the input bearing so I'm wondering why there is not more clearance.  I'll check to makes sure the input bearing is fully seated when I have time to go out in the garage next.  If this is the issue, it is very easy to fix.

Sunday, July 21, 2013

Output Shaft & Countershaft Rebuild

I delayed rebuilding the transmission to finish up a few home improvement projects.  I purchased a bearing press from Harbor Freight earlier this week to continue the rebuild process this weekend.  I spent a few hours this weekend and finished up the output shaft and countershaft rebuild.

There is not a great deal of work in preparing the countershaft for reinstall in the case.  You remove the bearing from the front and rear of the shaft, install the race in the back of the case, and install only the rear bearing (left side in picture above).  The front bearing must be installed on the countershaft while it is in the case as it will not fit into the case if installed first.

I installed the reverse gear shaft, reverse gear, and the rubber O ring into the case next and secured it with the roll pin.  The reverse gear itself is new but the remainder of these parts are original parts.  The shift shaft, spring, and shift lever were all install next as it would be much difficult to do so after the output shaft is installed.

The countershaft is held in place on the rear portion of the transmission with a race, followed by a shim, and then the retainer pictured above.  The endplay must be checked to ensure the endplay is between .001 and .005.  I used the original shim and the endplay was exactly .001.  I bolted the retainer in place and bent the tabs up so the bolts could not back out.  The picture also contains the gear which mounts to the end of the countershaft.

I slowly disassembled the output shaft taking pictures of all of the steps involved.  I thought I might document all of the steps but there are so many guides available I'm not sure that it would really benefit anyone.  I took pictures of every step nonetheless as I could then reference them later if needed.

Everything I needed for the rebuild of the output shaft was included in the M7000A kit except for one item.  A needle bearing set was not included for under the first gear.  There are three used and the kit came only with two of them.  I checked several internet sites and could not find a picture of a kit including the part.  I only found the picture below which shows the missing part with a label of 226.  The one I took out seemed to be in good condition so I decided I would reuse the part.

Once the output shaft was assembled, I placed it into the case.  I then mounted the lever which operates the reverse gear to the side of the case. 

During the upcoming week or next weekend, I'll do a little more work on the transmission.  I want to get it sealed up soon so nothing gets on the components or inside the case which should not be there. 

I have the original shifter which came with the transmission but I'm still looking for something reasonably priced to use instead.  I'd like to use a shifter which has positive stops.  This will keep me from damaging anything internal if I overshift.  Unfortunately, all the shifters with positive stops I've found on eBay are outside of my price range.