cygnusx1 Posted February 10, 2009 Share Posted February 10, 2009 I searched. I have swapped spedometer pinions in the past but this time I noticed that the pinion shaft is eccentric from the body. Nissan did this so that the same body could be used with different pinion diameters. So, I insert the pinion housing and rotate it until the pinion engages the output shaft I can sort of check backlash by grabbing the pinion shaft with a needle nose and wiggling it. My problem is that whenever I lock down the retainer screw on the trans housing, the output shaft becomes hard to turn by hand. I tried two different pinion housings and two different pinions but both of them cause the output shaft to tighten up a little. If I leave the retainer screw loose, the output shaft turns freely. Any advice? I looked at the MT section of the factory manual for the 82 Maximas...but didn't see anything about this. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted February 10, 2009 Share Posted February 10, 2009 It's my understanding (don't remember where I read this) that the pinion housing isn't supposed to be rotated to adjust backlash. Rather there are 2 positions: the regular position, and another where the pinion is rotated 180 degrees. The latter is for the larger gears used with the higher (numerically) ratio diffs, such as 3.9 and up. If you just align the pinion housing in one of those 2 positions, does that solve the binding issue? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 10, 2009 Author Share Posted February 10, 2009 I tried a couple of different random positions yesterday but both bound up the output shaft when I tightened down on the retainer. I will spend more time studying it tonight. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 23, 2009 Author Share Posted February 23, 2009 OK I got to the bottom of it. 1) It appears that when you change the gear size, you also need the appropriate pinion body. 2)There is a "cut" in the side of the body that looks like a place where you can use a flat screwdriver to pry the body out of the transmission. That slot is where the retaining tab goes. 3) When I rotate the body so that the original slot lined up with the retainer tab, the pinion was so far back off the drive gear on the output shaft that there was no meshing. I had to turn the body 180 degrees for the pinion to mesh with the drive gear. That meant that I had to grind a new slot 180 degrees from the original slot. Note: I have no idea what year/size pinion body I am using. It is made out of steel and had a black pinion on it for a 3.54 rear. I have seen most of them made out of aluminum, so I don't know for sure where it came from. Note: Don't tighten the retaining tab against the outer edge of the pinion body. Use the slot in the body. If you don't, the pinion gets pushed too far into the tranny and causes a bind and mis-alignment of the gears. Pictures would help. I'll try to get some. Quote Link to comment Share on other sites More sharing options...
X64v Posted February 23, 2009 Share Posted February 23, 2009 As far as I know there are three different speedo housings. The black steel one you have is meant for the 4 speeds and all automatics. The 81-83 5 speed transmissions have their retainer 180 degrees opposite of the 4 speeds and automatics, so their aluminum housings have their slots cut on the opposite side. There are two aluminum housings as far as I know, with the slots cut just a light bit off from each other. One is for the smaller gears, one for the bigger gears. I've held two side-by-side to confirm this. I can't say whether the early 5 speed transmissions use the steel or aluminum housings. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 23, 2009 Author Share Posted February 23, 2009 Interesting. If you are willing to cut a new slot, it looks like any of them can be made to work with any pinion. Quote Link to comment Share on other sites More sharing options...
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