Speedo Gear Question
Discussion
My speedo shop replaced the broken cable last year and it worked for a while and died. Now they say the cable and head unit are good so the problems is most likely the transmission gear... and off you should go in your odd little car to a transmission shop.
I've ordered a gear set but 2 questions:
1) Is changing the gear set a simple: jack-up car, remove the cable nut, remove capture plate & pull out old gears and replace (transmission in situ) or more complex? Any tricks or tips?
2) How likely is the gear bearing to have gone bad and does that mean considerably more access/effort to change?
Thanks Grady ('86 280i with 4 speed)
I've ordered a gear set but 2 questions:
1) Is changing the gear set a simple: jack-up car, remove the cable nut, remove capture plate & pull out old gears and replace (transmission in situ) or more complex? Any tricks or tips?
2) How likely is the gear bearing to have gone bad and does that mean considerably more access/effort to change?
Thanks Grady ('86 280i with 4 speed)
Question 1) Yes. Its a very simple job as you describe.
Question 2) Sorry I can't help.
From my own experience having replaced the cable and the drive gear and with assurance that the head is OK the speedo reads approx 1.5 times truew speed as measured by SatNav! Beware that there are four different speedo driven gear ratios available for this gearbox
PVN
Question 2) Sorry I can't help.
From my own experience having replaced the cable and the drive gear and with assurance that the head is OK the speedo reads approx 1.5 times truew speed as measured by SatNav! Beware that there are four different speedo driven gear ratios available for this gearbox
PVN
Should be easy to change on a Ford..usually just a small retaining bracket to release on the gearbox which holds the Speedo cog in.
You will need to give the supplier of the new (normally nylon) cog, the wheel and tyre size, plus gearbox and diff ratios, so that the correct part is supplied.
I've only replaced one on a Ford Essex V6 used in a non-standard situation, but the procedure should be pretty much the same.
You will need to give the supplier of the new (normally nylon) cog, the wheel and tyre size, plus gearbox and diff ratios, so that the correct part is supplied.
I've only replaced one on a Ford Essex V6 used in a non-standard situation, but the procedure should be pretty much the same.
Just to complete the thread...
On my 1986 U.S. 4 speed 280i, the transmission end of the cable in held in place by a 7/16 (head size) bolt through a capture plate (basically a "Y" shaped fitting). Jack or ramp up the the right front and slither under. The fitting is on the bottom 1/4 of the transmission. No worries except there is no space for "hands" and the frame, exhaust and rear transmission mount are all in the way.
A 1/4" socket on a long extension loosened - and finger tips then removed - the bolt and fork. A tug on exposed shaft pulled out the bearing (at least that is what I think the "bearing" is - a 3/4" round fitting that holds the gear into the transmission) and gear. My plastic gear (original and the replacement) had 18 teeth.
It looks like there should be something pinning the bearing and shaft together but not so. A gentle tap-tap on the end of the shaft with a hammer over a large socket drove the old gear & shaft out of the bearing. The old gear shaft had seized-up in the bearing and the plastic teeth were gone where the teeth should have meshed with the steel transmission gear. Also some metal flakes had annealed themselves to the plastic shaft. (That said, the shaft set didn't look too bad other than the missing teeth).
A good cleaning and fresh white grease is required. There is a large O ring on the exterior of the bearing that keeps the oil in the transmission, but since the O ring looked OK & it being Sunday night, I lubed the O ring and using an over-sized socked, tapped it home (making sure the gears meshed).
Slipped the cable into the square hole and all that was left was to start the 7/16 bolt and tighten it up. A mere 1 hour later THAT was done ... with a rest stop for a grapefruit Margarita and plenty of lubitory cursing (plus finding a bolt that got "lost" in the recesses of the transmission mount)!
Quick test run and the speedo is operational again! Easy but a PITA! Grady
On my 1986 U.S. 4 speed 280i, the transmission end of the cable in held in place by a 7/16 (head size) bolt through a capture plate (basically a "Y" shaped fitting). Jack or ramp up the the right front and slither under. The fitting is on the bottom 1/4 of the transmission. No worries except there is no space for "hands" and the frame, exhaust and rear transmission mount are all in the way.
A 1/4" socket on a long extension loosened - and finger tips then removed - the bolt and fork. A tug on exposed shaft pulled out the bearing (at least that is what I think the "bearing" is - a 3/4" round fitting that holds the gear into the transmission) and gear. My plastic gear (original and the replacement) had 18 teeth.
It looks like there should be something pinning the bearing and shaft together but not so. A gentle tap-tap on the end of the shaft with a hammer over a large socket drove the old gear & shaft out of the bearing. The old gear shaft had seized-up in the bearing and the plastic teeth were gone where the teeth should have meshed with the steel transmission gear. Also some metal flakes had annealed themselves to the plastic shaft. (That said, the shaft set didn't look too bad other than the missing teeth).
A good cleaning and fresh white grease is required. There is a large O ring on the exterior of the bearing that keeps the oil in the transmission, but since the O ring looked OK & it being Sunday night, I lubed the O ring and using an over-sized socked, tapped it home (making sure the gears meshed).
Slipped the cable into the square hole and all that was left was to start the 7/16 bolt and tighten it up. A mere 1 hour later THAT was done ... with a rest stop for a grapefruit Margarita and plenty of lubitory cursing (plus finding a bolt that got "lost" in the recesses of the transmission mount)!
Quick test run and the speedo is operational again! Easy but a PITA! Grady
Edited by Grady on Tuesday 11th May 05:22
Finding one of these speedo drive pinions was'nt easy. I was told by most that i would,nt get one new, but finaly tracked a supplier down in Germany. May help someone else out
http://www.oldcars.de/cgi-bin/shop/shop_en.pl?f=NR...
http://www.oldcars.de/cgi-bin/shop/shop_en.pl?f=NR...
Thanks for the link!
My speedo packed up last week, about six weeks after I fitted, and carefully routed, a brand new cable, so I am thinking it might be this part....
I hope there isn't a part in the LT77 gearbox that drives the speedo like there is in the Ford type 9 'box as fitted to my old (hateful!) Sierra XR4i, which needed a gearbox removal and partial strip down to fix the speedo drive!
???
My speedo packed up last week, about six weeks after I fitted, and carefully routed, a brand new cable, so I am thinking it might be this part....
I hope there isn't a part in the LT77 gearbox that drives the speedo like there is in the Ford type 9 'box as fitted to my old (hateful!) Sierra XR4i, which needed a gearbox removal and partial strip down to fix the speedo drive!
???Edited by ROOODBOY on Friday 14th May 01:39
That's the gear. Also available in the US from Marshall at CMW https://boaz.techsquared.net/cmw-tvr.com/shop_online.php and enter 280i & Speedometer to find the gear and bearing. 18 teeth is what mine had and it seems to be the correct size for a Ford 4 speed. Grady
After changing the gear, my speedo worked for a couple of weeks, then died w/o warning - less than 100 miles I'd guess.
I parked the car until October when I could get it inspected w/o an emission test.
Today I pulled the "new" gear and it is stripped on one face, just like the picture above and my old gear.
Playing with it, I notice if the gear and shaft are pressed all the way into the bushing, it turns easily. If it backs out just a bit, it get much stiffer.
How do you keep the gear all the way in against the bushing?
Or any other suggestions? (1986 Ford 2.8 & 4 speed) Thanks Grady
I parked the car until October when I could get it inspected w/o an emission test.
Today I pulled the "new" gear and it is stripped on one face, just like the picture above and my old gear.
Playing with it, I notice if the gear and shaft are pressed all the way into the bushing, it turns easily. If it backs out just a bit, it get much stiffer.
How do you keep the gear all the way in against the bushing?
Or any other suggestions? (1986 Ford 2.8 & 4 speed) Thanks Grady
Looking at the picture on a better screen, I realized that (unlike the picture) all my teeth are good except for 3-4 that are ground flat. Suggests the gear freezes and then strips its plastic teeth I'd guess. I'm thinking of chucking the new one up and sanding down the plastic shaft a tad.
ETA: And changing the O ring which it probably 26 years old too.
Grady
ETA: And changing the O ring which it probably 26 years old too.
Grady
Edited by Grady on Sunday 22 May 18:55
If you want to bin the cog drive new speedos are available from speedy cables that are driven from a sensor on prop, diff or driveshaft. It can be calibrated to run off pretty much any pulse I understand. Look at the link at the top of the griff forum.
I've gone for it but am using existing drive from LT77 electrical sender as ECU needs it anyway..
I've gone for it but am using existing drive from LT77 electrical sender as ECU needs it anyway..
Just tried to change the speedo cable on my '86 280i US spec and it looks like the tranny end does not go in far enough. It looks like it could be a case of seized/mangled plastic speedo gear.
I know, Grady you had changed yours. Can you pls let me know who/where you bought your part ? Also, you mentioned that your new part failed because of some fit issue. Did you figure it out ?
Anyone else that can point me to a supplier in the US and/or provide tips ?
Thanks !
MO
I know, Grady you had changed yours. Can you pls let me know who/where you bought your part ? Also, you mentioned that your new part failed because of some fit issue. Did you figure it out ?
Anyone else that can point me to a supplier in the US and/or provide tips ?
Thanks !
MO
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