Metzman510 Posted February 24, 2020 Author Report Share Posted February 24, 2020 Mike, my speedo drive looks like the longer one from the picture in this post, picture at the top of page 4 shows speedo drives side by side. The longer unit with the black gear on the left. Only mine has a white 19 tooth gear on it. https://ratsun.net/topic/19081-speedometer-gear-issues/page/4/ Quote Link to comment
datzenmike Posted February 24, 2020 Report Share Posted February 24, 2020 The 63 series ones are longer I think. I'll see if I can get the sleeve number and cross reference it to the 510 or the 200sx dogleg. Good picture to show the plastic gear is off set to the side of center line. 1 Quote Link to comment
Metzman510 Posted February 24, 2020 Author Report Share Posted February 24, 2020 That would be super helpful! Quote Link to comment
Crashtd420 Posted February 24, 2020 Report Share Posted February 24, 2020 The 63 series speedo drive will work but they are not 100% correct... I'm using a modified one in my stumpy, and I sent one to wayno to use in his ... You have to add a groove 180 degrees from the original.... and I believe wayno moved his groove closer to the edge... he said the the stumpy drive was about an 1/8 longer.. 1 Quote Link to comment
Crashtd420 Posted February 24, 2020 Report Share Posted February 24, 2020 The other 71b speedo drives will not work... they are too short.... 1 Quote Link to comment
Metzman510 Posted February 24, 2020 Author Report Share Posted February 24, 2020 Can somebody post a picture of a series 63 speedo drive as a reference? Quote Link to comment
Crashtd420 Posted February 24, 2020 Report Share Posted February 24, 2020 53 minutes ago, Metzman510 said: Can somebody post a picture of a series 63 speedo drive as a reference? That link you referenced has them... I believe that thread is me and wayno.... Quote Link to comment
Crashtd420 Posted February 24, 2020 Report Share Posted February 24, 2020 That thread also shows waynos info about how he modified his.... Screen shot for the hell of it... Stumpy 71b on left... 63 series on the right.... 1 Quote Link to comment
Crashtd420 Posted February 24, 2020 Report Share Posted February 24, 2020 Oh you'll need the little tab for a 63 series to hold it in place.... on the other one it's part of the assembly..... 1 Quote Link to comment
Metzman510 Posted February 24, 2020 Author Report Share Posted February 24, 2020 Thank you! 1 Quote Link to comment
datzenmike Posted February 25, 2020 Report Share Posted February 25, 2020 I dound the 12" extension housing used on the shorty.Looks like '84 and up. Having trouble picking out the shorty pinion.... Quote Link to comment
wayno Posted February 25, 2020 Report Share Posted February 25, 2020 What color does he need, a red one? They likely only had a few different ratios in the 2wd regular cab/short box trucks that had the short shaft, certainly not 4wd ratios as the speedo was in the transfer case and why would they change that to except to except a shorty transmission speedo drive pinion. Quote Link to comment
datzenmike Posted February 25, 2020 Report Share Posted February 25, 2020 21 tooth, purple I think. I looked through all the 63 series 510, 610/710/B21/620/S10/A10 and closest was a 19 tooth. You need a vehicle like a truck that needs a large tooth count to compensate for a large differential ratio. I worked late last night and was tired. I'm have another look tonight. Quote Link to comment
Metzman510 Posted February 25, 2020 Author Report Share Posted February 25, 2020 Wayno, I'm going to need a purple 21 tooth... Datzenmike, Thank you. Quote Link to comment
wayno Posted February 25, 2020 Report Share Posted February 25, 2020 (edited) I am doubting the short shaft ever came with that gearing/color, and your speedo is off by too much for just two gear ratios off, maybe 10mph off but not 40mph off, I would pull your instrument cluster and figure out what is messing it up, there is a magnet in there and maybe some metal shavings got on the magnet. Edited February 25, 2020 by wayno Quote Link to comment
Metzman510 Posted February 25, 2020 Author Report Share Posted February 25, 2020 wayno, I couldn't agree more. The 21 tooth is to correct the odometer, up 2 teeth from the 19 tooth that is in there currently. The speedometer definitely has a date with the cleaning, inspecting, and adjusting folks, I just wanted to try and get the odometer on the correct page also. Its a 2 sided attack, one to correct the odometer, the other to calibrate the speedometer. Quote Link to comment
wayno Posted February 26, 2020 Report Share Posted February 26, 2020 Even if the speedo is off, the odometer should only be off the 10 percent that the gear is off. Not sure if speedos are adjustable, I have only messed with a GM one a long time ago, it freaked out because I got some metal shavings on the magnet, that happened because I drilled some holes for warning lights near the speedo, I cannot recall if I replaced it or cleaned it, that was a long time ago. 1 Quote Link to comment
Metzman510 Posted February 26, 2020 Author Report Share Posted February 26, 2020 Yup, the odometer is off 13%, so I'm looking for a gear 2 teeth up from the 19 tooth that I have. It's like blackjack, I need a 21 to win. Quote Link to comment
datzenmike Posted February 26, 2020 Report Share Posted February 26, 2020 I wish I had the correct part number for the shorty pinion gear assy. The 720 only lists the entire assy., gear and sleeve together. It's hard to separate the regular 71B from the shorty. One 21 tooth was used on the S12 but I know it wasn't a shorty, only the truck got them and none of the 720s used a 21 tooth. Quote Link to comment
Metzman510 Posted February 26, 2020 Author Report Share Posted February 26, 2020 Do you have the assembly PN? It's a start... I would assume that the 21 tooth in the s12 is from some unusual optional variant? Quote Link to comment
mmerlinn Posted October 21, 2020 Report Share Posted October 21, 2020 Thread is a little old I know, but this may be of interest. The number (7202575) suggests that this transmission, assuming that the case is original to it, was built in Feb 1977. Quote Link to comment
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