Tranmission speedometer sender broke? WTF??
#17
944 transmission sender
i am having a similar problem to Dougs. Although, when i spin up the white gear connected to the sensor outside of the transmission the speedo works and so does the odometer.
So this makes me think there is a problem with the gear but it looks intact? could it be something inside the transmission that drives the white gear for the sensor?
speedos are so frustrating!
So this makes me think there is a problem with the gear but it looks intact? could it be something inside the transmission that drives the white gear for the sensor?
speedos are so frustrating!
#19
#20
Hey doug. Appreciate the offer! I was a speaking to a guy called dimi on another forum topic and it could be a drive gear that is attached to the diff and drives the long white pinion. Going to take a closer look and I'll let you know how I get on.
#22
Intermediate
Question on white pinion gear
this is a simple problem - take the sensor out of the trans. Take the white gear out of the trans. Put the square shaft from the gear into the sensor, turn on ignition (no need to start car), have friend watch while you spin the gear and if the speedo shows MPH, then the sensor and wiring are fine and you have a problem with the gear, which is what I suspect. here is a photo of the sensor and gear
http://thumbs3.ebaystatic.com/d/l225...fuxzt3onsg.jpg
http://thumbs3.ebaystatic.com/d/l225...fuxzt3onsg.jpg
#23
Rennlist Member
I known this is an old thread, but hoping William_b_noble or someone can help. I think I damaged the pulse sender doing an axle seal replacement. Speedo dead immediately after, and worked fine before. I have a "new" used sender coming today. I also purchased the white pinion gear gear because it's only $8. If I have to replace the white gear do I have to get the "sleeve" out of the transaxle or will it just pull out? Also, do I have to take off the CV again to seat the gear or just stick it down in there? And... finally, if I somehow damaged the round pinion ring inside the transaxle how hard it that to replace? Thanks for any help!
The black plastic sender can be threaded off with a little help from a 24 mm wrench, 12-point, if it is stuck. The aluminum bushing comes off with a 22 mm wrench or socket. The drive pinion is inserted, loose-ish, into the bore in the case.
When assembling, first put a little transmission oil into the bore to fill the pocket into which the bottom end of the pinion sits. Else you risk wearing out the plastic. I have replaced many that are worn (and keep them in stock). Put some high-pressure (thick) grease on the pinion teeth, and smear some on the pinion where it rides in the bushing. The factory does these things, for good reason. Thread the bushing in, 24 Nm tight. Thread the black plastic sender on, finger tight. Clip on the electrical connector.
You do not need to remove the CV to do any of this. If you are concerned about the green/grey drive gear, then remove the CV joint from the output shaft, back out the M8 center bolt, and pull out the output flange. You can probably replace the drive gear without removing the radial oil seal. It presses on but can sometimes take a little coaxing. Gently prying with a right-angle pick should work. Torque for the center bolt is 24 Nm.
If you're stuck for parts, PM me. Good luck.
Last edited by KevinGross; 01-28-2023 at 06:16 PM.
#24
Intermediate
Thank you! I took it apart today. I have a new gear. The old one came out intact but mashed up. Looked in the port for the sender with an endoscope, but couldn't tell much. I tried to install the new white pinion gear but it wouldn't go in far enough to put the bushing on. I wiggled it around but it wouldn't go in. Didn't want to force it. The old one was hard to get out with pliers and wouldn't go back in either. I plan on ordering the green/grey helical sprocket, but if you have one I would be glad to pay you for it. If I replace that, that'll be everything mechanical for the sender unit. I got a used speed sensor from Plyhammer's. I guess I could bite the bullet and get the only other option I know of which is a $220 refurb from 944Online. I really appreciate your help! If you have any other suggestions or thoughts I would appreciate it. I've only had the car since Jan 12, and being new to these cars, I mangled all this....
#25
Rennlist Member
Thank you! I took it apart today. I have a new gear. The old one came out intact but mashed up. Looked in the port for the sender with an endoscope, but couldn't tell much. I tried to install the new white pinion gear but it wouldn't go in far enough to put the bushing on. I wiggled it around but it wouldn't go in. Didn't want to force it. The old one was hard to get out with pliers and wouldn't go back in either. I plan on ordering the green/grey helical sprocket, but if you have one I would be glad to pay you for it. If I replace that, that'll be everything mechanical for the sender unit. I got a used speed sensor from Plyhammer's. I guess I could bite the bullet and get the only other option I know of which is a $220 refurb from 944Online. I really appreciate your help! If you have any other suggestions or thoughts I would appreciate it. I've only had the car since Jan 12, and being new to these cars, I mangled all this....
#26
Rennlist Member
Installed correctly, the pinion should sit proud as in these photos. If it's not, take a look down the bore for whatever is clogging things.