sirtokesalot Posted December 16, 2019 Share Posted December 16, 2019 i believe i know the issue but not sure if i can fix it. the replacement transmission came from a legacy. the legacy used 205 55 r16 and the outback uses 215 60 r16. how does the car know what the speed is from the transmission is it as simple as swapping the speed sensor from the old transmission or is it some small gear inside the transmission? Quote Link to comment Share on other sites More sharing options...
gbhrps Posted December 17, 2019 Share Posted December 17, 2019 sirtokesalot, Before you get too excited at the indicated speed vs actual speed, borrow a friend's Garmin GPS, throw it on the dash and take a short trip over various speeds to see how the speedometer reads when compared to the GPS indicated speed. My 2017 OBW runs 245/50/19's stock in summer and 215/60/17's on its winter tires (winter wheels and tires held over from my previous 2012 OBW). At 83 kmph (50 mph) speedometer indication, the Garmin GPS reads 80 kmph (52 mph). Similarly at 100 kmph (60 mph) the difference isn't much more. Try my suggestion and see if the difference is enough to warrant changing anything around. Myself, I just am aware that with my winter tires on I'm actually going 3 or 4 kmph slower that what the speedometer reads, so I up my speed accordingly so I don't cause a road rager behind me. 1 Quote Link to comment Share on other sites More sharing options...
sirtokesalot Posted December 17, 2019 Author Share Posted December 17, 2019 i have a gps and can confirm in saying that 25 mph is 22 on speedo 50 on gps is 45 on speedo 70 is 63 3 hours ago, gbhrps said: sirtokesalot, Before you get too excited at the indicated speed vs actual speed, borrow a friend's Garmin GPS, throw it on the dash and take a short trip over various speeds to see how the speedometer reads when compared to the GPS indicated speed. My 2017 OBW runs 245/50/19's stock in summer and 215/60/17's on its winter tires (winter wheels and tires held over from my previous 2012 OBW). At 83 kmph (50 mph) speedometer indication, the Garmin GPS reads 80 kmph (52 mph). Similarly at 100 kmph (60 mph) the difference isn't much more. Try my suggestion and see if the difference is enough to warrant changing anything around. Myself, I just am aware that with my winter tires on I'm actually going 3 or 4 kmph slower that what the speedometer reads, so I up my speed accordingly so I don't cause a road rager behind me. Quote Link to comment Share on other sites More sharing options...
Rampage Posted December 17, 2019 Share Posted December 17, 2019 4 hours ago, sirtokesalot said: is it as simple as swapping the speed sensor from the old transmission Yes. I've had to do it on ours. If it is a 4EAT AWD, I would swap both speed sensors. I haven't looked at MT. Quote Link to comment Share on other sites More sharing options...
el_freddo Posted December 17, 2019 Share Posted December 17, 2019 It won’t be the speed sensor, it will be the little drive gear in the gearbox. This means a gearbox split to swap it to the outback spec drive gear. You should be able to install and calibrate a vehicle speed sensor modifier/adjuster unit. It will require some wiring action and some calibration work when driving on the road. You will need a second person to complete this calibration. What you have is opposite to what gbhrps talks about, and that setup is dangerous in my opinion. It’ll be speed ticket bait too! Cheers Bennie Quote Link to comment Share on other sites More sharing options...
sirtokesalot Posted December 18, 2019 Author Share Posted December 18, 2019 (edited) 12 hours ago, el_freddo said: It won’t be the speed sensor, it will be the little drive gear in the gearbox. This means a gearbox split to swap it to the outback spec drive gear. You should be able to install and calibrate a vehicle speed sensor modifier/adjuster unit. It will require some wiring action and some calibration work when driving on the road. You will need a second person to complete this calibration. What you have is opposite to what gbhrps talks about, and that setup is dangerous in my opinion. It’ll be speed ticket bait too! Cheers Bennie i dident know a vehicle speed sensor modifier/adjuster unit was a thing. how would one go about doing this to an outback? im not splitting the transmission to swap that gear id leave it as is and use the gps for my speedo before i did that but would like to make it read more accurate if possible Edited December 18, 2019 by sirtokesalot Quote Link to comment Share on other sites More sharing options...
el_freddo Posted December 18, 2019 Share Posted December 18, 2019 Do an eBay search or ask at your local electronics store, they should have what you need Cheers Bennie Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 18, 2019 Share Posted December 18, 2019 Dakota Digital SGI-5E is one that I have used. Also the DCCD-Pro guys in canada make a VSS-Pro that does similar. It's just a square wave that pulses like 4000 or 8000 pulses per mile. You just need to to change the frequency of the sensor output. GD Quote Link to comment Share on other sites More sharing options...
86BRATMAN Posted December 18, 2019 Share Posted December 18, 2019 Is this a 4eat or 5mt? Quote Link to comment Share on other sites More sharing options...
sirtokesalot Posted December 18, 2019 Author Share Posted December 18, 2019 16 minutes ago, 86BRATMAN said: Is this a 4eat or 5mt? 4eat Quote Link to comment Share on other sites More sharing options...
el_freddo Posted December 19, 2019 Share Posted December 19, 2019 Auto, you should be able to pull the speedo drive gear and swap from what I understand of auto boxes. The sensor will be on the front diff housing as opposed to the manual box that has it midway down the side of the gearbox on the front half case. There might be an easy fix to this after all. Got the old box to pull the speedo drive cable from? Also - have you confirmed that this box is the same diff ratio as your old one? If there’s a ratio swap you’ll need to swap the rear diff too! Cheers Bennie Quote Link to comment Share on other sites More sharing options...
sirtokesalot Posted December 19, 2019 Author Share Posted December 19, 2019 2 hours ago, el_freddo said: Auto, you should be able to pull the speedo drive gear and swap from what I understand of auto boxes. The sensor will be on the front diff housing as opposed to the manual box that has it midway down the side of the gearbox on the front half case. There might be an easy fix to this after all. Got the old box to pull the speedo drive cable from? Also - have you confirmed that this box is the same diff ratio as your old one? If there’s a ratio swap you’ll need to swap the rear diff too! Cheers Bennie i do still have the old trans the new one is the same 4.44 ratio as the original one it just came from a legacy vs an outback. how would one get this speedo drive gear out without taking the trans apart? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted December 19, 2019 Share Posted December 19, 2019 50 minutes ago, sirtokesalot said: i do still have the old trans the new one is the same 4.44 ratio as the original one it just came from a legacy vs an outback. how would one get this speedo drive gear out without taking the trans apart? pull the retaining plate on the passengers side and see if there's a way to get the plastic drive gear bits out. if you need to reuse that front diff, mark the retaining ring location and number of turns to remove it so you can reinstall it in the same position. Quote Link to comment Share on other sites More sharing options...
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