Speedo not working - Speedo drive issue? (1 Viewer)

[AndrewNZ]

Hey all, long time lurker - first time poster.

Trying to trouble shoot why my Speedometer isn't working.

Speedo cluster will read when turning the drive manually
Speedo cable isn't broken and each end will turn simultaneously - cant be separated by pulling on each end
Speedo drive gear is in good condition, have tried a second unit just incase 6x16 drive
Worm drive inside transfer case will turn with the drive shaft and looks visually to be okay

Trouble shooting from here I believe I have narrowed it down to the drive gear and worm gear arent engaging and I cant work out why.
Install the drive and running the vehicle on axle stands I cant see the drive output spinning at all
Comparing to google images I cant spot any issues with my unit.

Any thoughts or suggestions I could try?

 

[Gimme a 60]

Did you check the shims in the worm gear?

Maybe that’s your issue - they are worn and don’t want to mesh properly.

 

[AndrewNZ]

Did you check the shims in the worm gear?

Maybe that’s your issue - they are worn and don’t want to mesh properly.

Hey,

No I have not. is that internally in the transfer case? how do I go about checking those?

 

[Gimme a 60]

Hey,

No I have not. is that internally in the transfer case? how do I go about checking those?

Not really.

You will have to take off the bearing race/retainer, it’s not an overly hard job.

You have to remove the rear companion flange, and Take the stake nut off, you can use a impact.

Once the companion flange is off, remove the 10 14mm bolts (I’m just going off of memory so don’t quote me)

Then the whole retainer/race will come off, and you will be able to inspect the little metal worm gear. Nothing holds it on, really - you can slide it off by hand. However that’s when you will find the small shim in between the worm gear and the the output shaft. I hope I’m making sense.

While you are in there, you can check the race for pitting, and the bearing. Well worth it in my opinion. - you shouldn’t have to drain the transfer case fluid.

(When you put the companion flange back on remember to torque to 94ft pounds).


I will send a bunch of pictures showing you what I did when I get home from work.


Hope this helps.

 

[AndrewNZ]

Not really.

You will have to take off the bearing race/retainer, it’s not an overly hard job.

You have to remove the rear companion flange, and Take the stake nut off, you can use a impact.

Once the companion flange is off, remove the 10 14mm bolts (I’m just going off of memory so don’t quote me)

Then the whole retainer/race will come off, and you will be able to inspect the little metal worm gear. Nothing holds it on, really - you can slide it off by hand. However that’s when you will find the small shim in between the worm gear and the the output shaft. I hope I’m making sense.

While you are in there, you can check the race for pitting, and the bearing. Well worth it in my opinion. - you shouldn’t have to drain the transfer case fluid.

(When you put the companion flange back on remember to torque to 94ft pounds).


I will send a bunch of pictures showing you what I did when I get home from work.


Hope this helps.

Appreciate the help, pictures would be great!

 

[Gimme a 60]

It’s simple, and you get to see the condition of the race.

Just be careful when removing the retainer - there is a gasket that can be reused.

If you need to add a shim to the worm gear, you may want to check the preload on the race- perhaps you will have to add a shim there too.

 

[AndrewNZ]

I owe you a box of beers or something mate. You’re on the money !

Just put my finger in the hole and I can turn the worm gear very easily by hand with the drive shaft station. It’s under little tension so it imagine it’s not driving the Speedo at all

 

[Gimme a 60]

I owe you a box of beers or something mate. You’re on the money !

Just put my finger in the hole and I can turn the worm gear very easily by hand with the drive shaft station. It’s under little tension so it imagine it’s not driving the Speedo at all

You can buy a coke for me - I’m 17.


Good luck.

 

[Eurasiaoverland]

It’s simple, and you get to see the condition of the race.

Just be careful when removing the retainer - there is a gasket that can be reused.

If you need to add a shim to the worm gear, you may want to check the preload on the race- perhaps you will have to add a shim there too.

A few points
-there is a (one) shim between the speedometer drive gear and the companion flange. This is a set thickness and there is no procedure for adding/changing shims here. The pre-load shims in the bearing race retainer won't affect the drive gear (though indeed pre-load is worth checking) - that needs to be done before disassembly of course. As the speedometer drive gear is a worm gear, moving it up and down the shaft by the thickness of that shim will not in my opinion affect the engagement with the speedometer driven gear. I would be checking to see that the spacer sleeve is in the correct place - between the tapered roller bearing and the speedometer drive gear, as in your picture.

The oil will definitely need to be drained before removing the rear bearing retainer, or it will spill out when you crack the gasket. The paper gasket is not reusable.

I owe you a box of beers or something mate. You’re on the money !

Just put my finger in the hole and I can turn the worm gear very easily by hand with the drive shaft station. It’s under little tension so it imagine it’s not driving the Speedo at all

Have you ever had the spedometer working, or is this a new-to-you vehicle which has always had this problem?

Are you saying the speedometer drive gear moves freely on the output shaft? I find it hard to believe that the drive gear splines could have completely worn away, surely the plastic driven gear would get stripped if something was seized. Are you sure it does not just feel like it's moving?

If you have never see the speedometer work, perhaps there are some incorrect parts installed?

As I said in my message on the BJ70 (I think) group - post a picture of what you've got.

EO

 

[AndrewNZ]

A few points
-there is a (one) shim between the speedometer drive gear and the companion flange. This is a set thickness and there is no procedure for adding/changing shims here. The pre-load shims in the bearing race retainer won't affect the drive gear (though indeed pre-load is worth checking) - that needs to be done before disassembly of course. As the speedometer drive gear is a worm gear, moving it up and down the shaft by the thickness of that shim will not in my opinion affect the engagement with the speedometer driven gear. I would be checking to see that the spacer sleeve is in the correct place - between the tapered roller bearing and the speedometer drive gear, as in your picture.

The oil will definitely need to be drained before removing the rear bearing retainer, or it will spill out when you crack the gasket. The paper gasket is not reusable.



Have you ever had the spedometer working, or is this a new-to-you vehicle which has always had this problem?

Are you saying the speedometer drive gear moves freely on the output shaft? I find it hard to believe that the drive gear splines could have completely worn away, surely the plastic driven gear would get stripped if something was seized. Are you sure it does not just feel like it's moving?

If you have never see the speedometer work, perhaps there are some incorrect parts installed?

As I said in my message on the BJ70 (I think) group - post a picture of what you've got.

EO

hey mate,

No i have never had the speedo running in my ownership.
You may be right and it only feels like it is moving. I may need to pull the back of the transfer off and see whats going on.

 

[AndrewNZ]

Speedo drive as pictured

 

[AndrewNZ]

I also took this from inside the transfer case. Does this look right? It looks like something is partially covering the worm drive.

 

[Godwin]

Are you certain the speedo cable is good? Can you pull the inner cable out of the sheath?

Speedometer issues are usually easy to fix, it's either the nylon drive gear, the cable, or the speedometer housing.

 

[Eurasiaoverland]

Everything in your pictures looks fine to me. I would suspect the cable.

To be sure of the drive gear/driven gear connection, turn the transfer rear output flange with the speedo pickup installed and bolted up, but without the cable. Put a screwdriver blade in the end of the driven gear shaft and see if you can hold it still while turning the flange. This should confirm that the problem is elsewhere.

 

[AndrewNZ]

Are you certain the speedo cable is good? Can you pull the inner cable out of the sheath?

Speedometer issues are usually easy to fix, it's either the nylon drive gear, the cable, or the speedometer housing.

Im fairly confident the cable is good. I can turn it by hand to operator the speedo. If I pull it through the sheath at one end, it retracts at the other

 

[AndrewNZ]

Everything in your pictures looks fine to me. I would suspect the cable.

To be sure of the drive gear/driven gear connection, turn the transfer rear output flange with the speedo pickup installed and bolted up, but without the cable. Put a screwdriver blade in the end of the driven gear shaft and see if you can hold it still while turning the flange. This should confirm that the problem is elsewhere.

If install the speedo drive into the transfer, and put the rear axle in the air and put the car into a drive gear, I cant see the gear driven shaft move at all. Which is why I think the worm gear isn't engaging or driving the speedo drive.

 

[Eurasiaoverland]

If install the speedo drive into the transfer, and put the rear axle in the air and put the car into a drive gear, I cant see the gear driven shaft move at all. Which is why I think the worm gear isn't engaging or driving the speedo drive.

I think it's worth taking off the rear propeller shaft and getting a feel for the (lack of) engagement between the drive and driven gear by doing the above mentioned test. If it fails the test, then take of the rear bearing retainer and investigate.

 

[AndrewNZ]

I think it's worth taking off the rear propeller shaft and getting a feel for the (lack of) engagement between the drive and driven gear by doing the above mentioned test. If it fails the test, then take of the rear bearing retainer and investigate.

When I turn the prop shaft I can see the drive gear moving and I can’t stall it with my finger.

(Must of felt like it was slipping before when it actually wasn’t)

Install the Speedo drive and still not movement. I can manually turn it irrespective to prop shaft position or movement but it’s “notchy”

 

[Eurasiaoverland]

OK, that's progress. Perhaps you have mismatched drive and driven gears.

There are at least 2 different sizes of drive gear on the 60. The standard one is 6:15-17, meaning the drive gear has 6 worm 'teeth' and fits 15-17 toothed driven gears. I think you mentioned that your driven gear was 6x16, meaning it has 16 teeth and fits the tooth spacing of a 6-toothed drive gear.

Once you get driven gears with larger numbers of teeth, e.g. 18-20, which are found in the LJ70 for example, the driven gear becomes wider and the drive gear must be narrower (smaller radius, not width) to maintain the same 6 tooth pattern.

So it could be that you have a 6:18-20 drive gear which does not engage with your 6x16 driven gear. The next step would be to remove the rear bearing retainer and take out the drive gear (no special tools needed, it pulls off by hand) and check. The gear should be stamped with something like 15-17. They are still available new and are cheap to buy.

All this assumes you are pushing the speedometer driven gear sleeve fully home in the bore and securing it with the locking tab.

Another thing to check maybe is the orientation of the rear bearing retainer. While I don't see that it would make a difference, it is possible to install the retainer in the wrong orientation. You can check by matching the tabs on the retainer and transfer case.

 

[AndrewNZ]

OK, that's progress. Perhaps you have mismatched drive and driven gears.

There are at least 2 different sizes of drive gear on the 60. The standard one is 6:15-17, meaning the drive gear has 6 worm 'teeth' and fits 15-17 toothed driven gears. I think you mentioned that your driven gear was 6x16, meaning it has 16 teeth and fits the tooth spacing of a 6-toothed drive gear.

Once you get driven gears with larger numbers of teeth, e.g. 18-20, which are found in the LJ70 for example, the driven gear becomes wider and the drive gear must be narrower (smaller radius, not width) to maintain the same 6 tooth pattern.

So it could be that you have a 6:18-20 drive gear which does not engage with your 6x16 driven gear. The next step would be to remove the rear bearing retainer and take out the drive gear (no special tools needed, it pulls off by hand) and check. The gear should be stamped with something like 15-17. They are still available new and are cheap to buy.

All this assumes you are pushing the speedometer driven gear sleeve fully home in the bore and securing it with the locking tab.

Another thing to check maybe is the orientation of the rear bearing retainer. While I don't see that it would make a difference, it is possible to install the retainer in the wrong orientation. You can check by matching the tabs on the retainer and transfer case.

Thanks ! I think the next step is remove the rear cover on the transfer case.

I also wondered about having a 16x6 Speedo drive meaning the worm gear should have 6 teeth when mine has 4 maybe 5 visible teeth.

I also sent you a couple videos on Facebook too!