Whelp, my speedometer quit working a little while ago, so I checked it out this morning. Works fine from the bottom of the cable up. Took the driven gear out, somewhat worn, then got a mirror and spotted the drive gear in there (3 spd). Looks worn down lots to me. Anyone know where to find these parts? Be nice to put in both new ones. Also be nice not to take this apart until I have replacements. Couldn't seem to find anything on searches. Thanks for any help. Bob
Question Bob - Is the worn out gear in the transmission? or the speedo adapter? Patrick's sells the speedo adapter gear for the 3:55.
3.55 adapter It's the drive gear (not the driven gear) on the transmission shaft that is worn almost flat. The driven gear is not in too bad of shape, it's metal, not plastic. I looked on Patrick's website but didn't see a 3.55 adapter. Do you know where it fits? If it takes the place of the driven gear I might as well put one in, as my speedometer has always been off. Just got back from AAR (I've got the week off). They have several out there, but going to have to get mine apart first to match it. Either that or pull one out of one of their junk transmissions. Can't do it today and we're right between rainstorms this week...no hurry I guess. Bob
Bob, The Worm Gear on the mainshaft is apparently different for the driven gear and the rear-end gear ratio. I'm going through this myself at the moment. I have patrick's driven gear for my 3:55 rearend, but I'm still 10 MPH or so off. The worm gear is different on the mainshaft. Call Patrick and speak to him directly to get the straight poop! I have the rear end, and correct speedo gear, but I'm off. I think now for the third time I have to drop the tranny and put the right worm gear in!! Its getting old. Flashlight
Go to the 700R4 site or Bow Tie overdrive site where you can plug in your rear end ratio and tire size and it will show the drive gear and driven gear needed to give the correct reading. You will have to pull the tail housing to remove the drive gear; it is held on by either a spring loaded ball bearing or a spring clip that catches the top of the keyway groove. On some of the earlier ones the drive gear has a light press fit so knock it off with an aluminum or brass drift if trying to save. Don't hammer a new one on but use a pipe that just fits over the output shaft and catches the drive gear inside the gear teeth. The teeth on the drive gear taper to a thin edge and bend VERY easily if struck. Most of the press on gears do not fit up against a shoulder so scratch on each side of the old gear with an awl before removing or measure carefully from the end of the shaft so the new one will be positioned right.
3.55 drive (worm) gear Thanks for the replies. The adapter sold by Patrick's that Larry was talking about is one that fits between the driven gear assembly (where the cable plugs in) and the cable itself. From what you're saying (Flashlight), it sounds like Patrick's sells a drive (worm) gear and driven gear setup that is matched to 3.55 rear end gears. Correct? I'll give him a call later on today and see what he has to say. Also (Evan), I looked up the calculator and it comes out 13 teeth for the drive gear and 31 teeth for the driven gear (seems like a lot). Thanks lots to you both!! Bob
Your tire size can also throw your speedo off. You might have the correct gear combo with a different set of tires. Seems to me there was a book that told what color gear or which gear needed to be used with which tire and rear end gear combo......Big Tim
