FJDatto Posted July 17, 2008 Report Share Posted July 17, 2008 Dogleg is making the speedo read high. Anyone know the proper tooth count on the speedo gear that will slow it down to the proper reading. Note: I've searched to no avail. No doubt, the info is directly in front of me. Quote Link to comment
zerow Posted July 17, 2008 Report Share Posted July 17, 2008 Dogleg is making the speedo read high. Anyone know the proper tooth count on the speedo gear that will slow it down to the proper reading. Note: I've searched to no avail. No doubt, the info is directly in front of me. The speedometer is driven by the gear in the transmission that is installed when your differential was installed. Did you change your diff? If so, you will need the corresponding colored gear: YELLOW is the 16 tooth for the 3.36 BLACK is the 17 tooth for the 3.54 BLUE is the 18 tooth for the 3.70 WHITE is the 19 tooth for the 3.90 RED is the 20 tooth for the 4.11 PURPLE is the 21 tooth for the 4.38 (Sometimes color doesn't matter, count the teeth to be absolutely sure) (thanks to original contributor Z Garage Engineering LLC) Another contributing factor is wheel size, but that gets into a whole different set of calculations. Hope this helps. Quote Link to comment
datzenmike Posted July 17, 2008 Report Share Posted July 17, 2008 Dogleg is making the speedo read high. Anyone know the proper tooth count on the speedo gear that will slow it down to the proper reading. Note: I've searched to no avail. No doubt, the info is directly in front of me. If you still have the old tranny, just put speedo drive cog from it, into the dog leg. Think of the drive cog as not really part of the tranny but a matched part of the differential. When you swap the tranny out the cog goes in the new one. Quote Link to comment
FJDatto Posted July 17, 2008 Author Report Share Posted July 17, 2008 Thanks for the information... I do not have the old auto tranny from my wagon. I'll see what I can do to find one. I have a spare 17 tooth gear, but probably need the 18. Quote Link to comment
OL YELLER Posted July 18, 2008 Report Share Posted July 18, 2008 The speedometer is driven by the gear in the transmission that is installed when your differential was installed. Did you change your diff? If so, you will need the corresponding colored gear: YELLOW is the 16 tooth for the 3.36 BLACK is the 17 tooth for the 3.54 BLUE is the 18 tooth for the 3.70 WHITE is the 19 tooth for the 3.90 RED is the 20 tooth for the 4.11 PURPLE is the 21 tooth for the 4.38 (Sometimes color doesn't matter, count the teeth to be absolutely sure) (thanks to original contributor Z Garage Engineering LLC) Another contributing factor is wheel size, but that gets into a whole different set of calculations. Hope this helps. Where can these gears be bought from...........are they still available?............what is the procedure for changing the gears?..........thanx Quote Link to comment
datzenmike Posted July 18, 2008 Report Share Posted July 18, 2008 Dealer might have them, they were used through the 720s likely through the D-21s? 'C' type trannys. They are about 4-5 " long and often aluminum with a colored plastic gear or cog on the end. There is a rubber O ring to keep the oil in the tranny. If the tranny has oil in it this can get messy. I pull them from trannys on the scrap pile but most are blue I did find a black and a red. Just unscrew the speedo cable and put out of the way. Remove the 10mm bolt and the flat edged washer that fits into the slot on the drive cog. Make sure you replace it back in with the slot ligned up with the bolt and washer. Do not twist it when removing or putting back in or you will damage the meshed plastic gear. Supposidly you can take the plastic gear off the aluminum drive and replace with another, but the new cog would be a different diameter and when put back in the original place the gears would be out of mesh. I could not find a proper explanation for this so I change the drive with the cog on it. Quote Link to comment
zerow Posted July 19, 2008 Report Share Posted July 19, 2008 Thanks for the information... I do not have the old auto tranny from my wagon. I'll see what I can do to find one. I have a spare 17 tooth gear, but probably need the 18. You need one from an old auto transmission? I may have one, I will check this weekend. Quote Link to comment
ggzilla Posted July 19, 2008 Report Share Posted July 19, 2008 So using a speedo drive gear with more teeth makes the speed slower or faster? Quote Link to comment
datzenmike Posted July 19, 2008 Report Share Posted July 19, 2008 Makes the speedo read s l o o o o w e r Quote Link to comment
FJDatto Posted July 19, 2008 Author Report Share Posted July 19, 2008 You need one from an old auto transmission? I may have one, I will check this weekend. Let me know what you want for it. Thanks Quote Link to comment
Gensaiken Posted July 19, 2008 Report Share Posted July 19, 2008 Hmm, looks like I'm going to have to figure out my ratio and get a new speedo gear. Been driving with out my speedo working for almost a year. :lol: When I take my car to shops they always see the same milage as last time. They aren't quite sure what to do! Quote Link to comment
zerow Posted July 20, 2008 Report Share Posted July 20, 2008 When I take my car to shops they always see the same milage as last time. They aren't quite sure what to do! When I took my 610 to a shop the last time, they didn't know what it was! "What is that thing...?" Quote Link to comment
FJDatto Posted July 23, 2008 Author Report Share Posted July 23, 2008 You need one from an old auto transmission? I may have one, I will check this weekend. What did you find out? ;) Quote Link to comment
zerow Posted July 23, 2008 Report Share Posted July 23, 2008 What did you find out? ;) Sorry FJ, I was at the house, but did not get to the transmission. I will be in town on Friday, wielding tools. I will pull it then. Sorry about the delay! Quote Link to comment
FJDatto Posted July 23, 2008 Author Report Share Posted July 23, 2008 No problem. Let me know what you find out. Also, if you could give me a tooth count while you're at it. Thanks! Quote Link to comment
denveratsun Posted July 26, 2008 Report Share Posted July 26, 2008 Having a tough time getting this piece figured out... Datzenmike says that more teeth make it read slower... I just got finished pulling the speedo drive from the 280Z trans and it's blue (18 teeth) so I pulled the drive gear from the stock 4 speed trans and it's black (17 teeth) Problem is that I have about 10 mph difference since I swapped transmissions and went to the 5 speed. It is reading too fast. Seems like if I went to all the trouble to try and dissassemble the drive gear housings to swap plastic gears that I would actually be going tin the wrong direction (?) Same tires (although I did just get a screaming deal on some 17 inch '08 Yukon rims that look really great!)...same speedo cluster...same guy driving:mellow:...but 10 mph too fast. so... what do you think? Should I switch the gears? Seems like going back to what I had before would fix it right? The housings are WAY different so swapping the whole thing is out of the question. ????:confused: Quote Link to comment
datzenmike Posted July 27, 2008 Report Share Posted July 27, 2008 http://i138.photobucket.com/albums/q251/datzenmike/00270018.jpg[/img]"] Here's some I have collected. The left one may be out of an older F4W63 like in a 510 or 521?? Anybody recognise it?? The middle FS5W71B and right maybe a 5spd or maybe F4W71B http://i138.photobucket.com/albums/q251/datzenmike/transcogs.jpg[/img]"] Take a good look at these, they are for FS5W71B trannys, there's one for '77-'80 and another kind for '81-'83. Are they even close to what is used in a dog leg?? Quote Link to comment
MikeRL411 Posted July 27, 2008 Report Share Posted July 27, 2008 When I took my 610 to a shop the last time, they didn't know what it was! "What is that thing...?" You know you have a problem when your car is older than the mechanic that is working on it! I have a 1967 RL411 and put cuctom "67RL411" plates on it so that the dealer would have half a chance of recognizing what model it is. Thankfully several of his old hands know full well what a jewel this car is, having worked for the DATSUN USA race team many years back. Quote Link to comment
datsun dreamer Posted July 27, 2008 Report Share Posted July 27, 2008 You know you have a problem when your car is older than the mechanic that is working on it! I have a 1967 RL411 and put cuctom "67RL411" plates on it so that the dealer would have half a chance of recognizing what model it is. Thankfully several of his old hands know full well what a jewel this car is, having worked for the DATSUN USA race team many years back. You must have read my mind:)! True, Oh, So true! Great words Mike:)! Quote Link to comment
zerow Posted July 27, 2008 Report Share Posted July 27, 2008 You know you have a problem when your car is older than the mechanic that is working on it! I have a 1967 RL411 and put cuctom "67RL411" plates on it so that the dealer would have half a chance of recognizing what model it is. Thankfully several of his old hands know full well what a jewel this car is, having worked for the DATSUN USA race team many years back. I'm hurt MikeRL411! My 610 IS older than me! Quote Link to comment
zerow Posted July 27, 2008 Report Share Posted July 27, 2008 No problem. Let me know what you find out. Also, if you could give me a tooth count while you're at it. Thanks! I have a RED 20 tooth cog wheel with speedo drive (the housing is trash, stripped) for 4.11 gears, it should work. If interested, just PM me, I'll cahrge you postage only. Quote Link to comment
FJDatto Posted July 27, 2008 Author Report Share Posted July 27, 2008 Thanks for the offer. Let me pull mine out first thing tomorrow morning and I'll count the teeth. For some reason, Needing a gear with 18 teeth is floating in the back of my mind. I'll confirm and let you know first thing! Quote Link to comment
datzenmike Posted July 27, 2008 Report Share Posted July 27, 2008 Take some pix of both the stock and the dog leg. Really want to see what a dog leg one looks like. Quote Link to comment
denveratsun Posted July 28, 2008 Report Share Posted July 28, 2008 Great to see the pics up here Datzenmike! It really helps a lot. The one on the left is exactly the same as the one the I pulled out of my old 1971 521 4speed, (all steel in construction) with the black gear. The one in the middle is exactly what I pulled out of the JY 5speed (now helping my gas mileage in my truck:)) from a 1978 280z with a blue gear...after looking at all the 5speed threads I could find, it seems that the trans is newer than the car I pulled it from. Your dates in the pic seem to confirm this as well. I am left with the thought that I should just get used to my speedo reading 10 over eh? The black gear has less teeth, which, as far as my logic and mechanical understanding go, would speed up the reading. So I guess that I am looking for the white gear eh? what baffles me is the flawless and accurate speedo performance prior to the trans swap.:blink: Quote Link to comment
FJDatto Posted July 28, 2008 Author Report Share Posted July 28, 2008 Okay, my dogleg has 18 teeth. Here are some pictures: Zerow, you have a PM. Quote Link to comment
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