I think the plastic gears in the transfer case have finally worn out and not giving a good speedometer reading. What is the process for moving these gears? Does anyone have a tutorial? I've looked on YouTube as well as I hate mud and found nothing. Perhaps I'm searching with the wrong keywords
Speedometer Gear removal from t-case (1 Viewer)
- Thread starter cvan1971man
- Start date
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Green Bean
SILVER Star
There is a nomenclature that you may want to become familiar with:
DRIVE GEAR: INSIDE THE T-CASE
DRIVEN GEAR: PLASTIC GEAR OUTSIDE OF THE T-CASE.
The Drive Gear tooth count should match the Driven Gear tooth count. It is a very easy process to remove the plastic Driven Gear to do a quick inspection.
DRIVE GEAR: INSIDE THE T-CASE
DRIVEN GEAR: PLASTIC GEAR OUTSIDE OF THE T-CASE.
The Drive Gear tooth count should match the Driven Gear tooth count. It is a very easy process to remove the plastic Driven Gear to do a quick inspection.
- Thread starter
- #3
Ok, how do I get the driven gear out? From talking to specter they said that it can be removed without dropping the transmission but they did not go into further detail
firemanj92
SILVER Star
Undo #87 (drivers/bottom side of transfer case) and slide keeper #86 out of way, remove Driven gear/sleeve by pulling
Transfercase 1963-8/80 - Specter Off-Road - https://www.sor.com/cat/068
Transfercase 1963-8/80 - Specter Off-Road - https://www.sor.com/cat/068
Living in the Past
SILVER Star
The gear pitch needs to match but certainly not the count. Most drive gears have a six and is a worm gear. Driven gear usually have two and half to three times the gear count on the US imported model FJ40. Fewer teeth on the driven gear the faster it spins the speedometer cable compared to the driveshaft.
If you have a '71 fj40 as indicated in your name, I believe you should have a 17 tooth gear. See part identified as 33403 and p/n 33403-60016.
Once you're under the truck, you'll see how easy everything is. Follow your speedometer cable to the t-case. Unscrew the speedometer cable from driven gear housing. There is either a 10mm or 12mm bolt on the housing that needs to be loosened up. That bolt holds down a little metal plate that you should now be able to rotate out of the way. Once the plate is rotated out of the way, get a flat head screw driver and use it to pry the speed driven gear housing out from the t-case (might be a bit stuck in there from years of dirt and grime) . There will be a notch where you can put the screw driver in, this notch is where that little metal plate was secured into.
- Thread starter
- #8
I pulled the driven gear and looked at the gears and I didn't see any gears torn up, nothing stripped, etc. how can I tell if the driven gear is bad
- Thread starter
- #9
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Green Bean
SILVER Star
Thank you for the clarification. The steel drive gear should have a number stamped into it. And the nylon gear has to match.
so just clarifying, the speedometer needle on your speedometer gauge does move when you use a drill?
if that is the case, im just guessing as im no expert, the end of the speedometer cable has a little metal bump that lines up with a slot cut into the gear driven housing. You need to make sure the speedometer cable part goes into that slot correctly so it mates up together and spins when everything is running. If you do that and your speedometer needle still doesn't move, then maybe the driver gear inside the T-case is missing? was your t-case rebuilt recently too? If so, maybe when it was being assembled, someone forgot to put that gear back in place. The Driver gear sits behind the parking brake drum. You would need to remove your rear drive shaft, parking brake drum and plate, then unbolt the rear box-like thing on the back of your T-case. The gear itself is round and maybe 1/2 wide and sits within that part of the t-case. A bit of work to get to, but it's quite easy to access without having to do anything major. Just time consuming. Before you do all that that though, lets try to rule some things out before doing unnecessary work. Also, maybe just make sure that the cable is installed correctly into the speedometer gauge. Early style cables are screw on, later style i believe are push on clips.
if that is the case, im just guessing as im no expert, the end of the speedometer cable has a little metal bump that lines up with a slot cut into the gear driven housing. You need to make sure the speedometer cable part goes into that slot correctly so it mates up together and spins when everything is running. If you do that and your speedometer needle still doesn't move, then maybe the driver gear inside the T-case is missing? was your t-case rebuilt recently too? If so, maybe when it was being assembled, someone forgot to put that gear back in place. The Driver gear sits behind the parking brake drum. You would need to remove your rear drive shaft, parking brake drum and plate, then unbolt the rear box-like thing on the back of your T-case. The gear itself is round and maybe 1/2 wide and sits within that part of the t-case. A bit of work to get to, but it's quite easy to access without having to do anything major. Just time consuming. Before you do all that that though, lets try to rule some things out before doing unnecessary work. Also, maybe just make sure that the cable is installed correctly into the speedometer gauge. Early style cables are screw on, later style i believe are push on clips.
pb4ugo
SILVER Star
Why do you have 2 post on the same subject when one will do? What's up with #2? You spin the cable and the speedo doesn't move? Doesn't that indicate something wrong with the speedo or the cables connection?
if spinning the cable doesn’t move the needle it’s something wrong with the cable or the gauge itself. not inside the transfer case. also make sure you spin it the right way otherwise the needle won’t move either. i believe it’s counter clockwise but not 100% sure off hand
- Thread starter
- #14
Speedometer is stoppedworking. Here is what I have done
1. Had the speedo rebuilt about 12 months ago.
2. Pulled the speedo cable from the tcase while still connected to the speedo. Ran the drill on reverse and the speedo did not move.
3. Pulled the speedo cable on both ends and ran the drill - the cable spend on the speedo side.
4. Pulled the driven gear. Could not see any gear damage
What ideas or recommendations do you recommend?
1. Had the speedo rebuilt about 12 months ago.
2. Pulled the speedo cable from the tcase while still connected to the speedo. Ran the drill on reverse and the speedo did not move.
3. Pulled the speedo cable on both ends and ran the drill - the cable spend on the speedo side.
4. Pulled the driven gear. Could not see any gear damage
What ideas or recommendations do you recommend?
Yeah I spun it counterclockwise
My only other recommendations is to take the cable out from the sheathe and clean it. Then grease it with light grade grease (not some super tacky sticky grease). Was your speedometer working shortly after it was rebuilt then it suddenly stopped working? Or was it not working from the get-go? Maybe the worm gear inside the speedometer itself is busted. I'm running out of ideas.
- Thread starter
- #16
It was working for a year and about 5000 miles. Put a new speedo cable in at the same time the cluster was rebuilt. Grease the cable with light lithium grease
if your cable is turning at both ends but still no joy at the needle then it’s something inside the speedometer cluster itself. if it was a problem in the transfer case then manually spinning the cable should make it work. i think you’re chasing the wrong end. you’ll need to pull your gauge cluster and start looking there i think
pbgbottle
Forum Lifer
Pull the bolt remove the tang and pull out the gear housing. When installing the new one make sure it is correct tooth count and seated all the way or it will strip the new Plastic gear in a few hours.
Here are a couple links I posted info on part numbers gears and what gears will match the drive gears.
2 drive gears 4 plastic gear option. Not all can be mixed and matched.
Old threads below for sure. 2006 2007. I’ve been hanging around ih8mud way too long. lol.
Links to threads.
Speedo gear - https://forum.ih8mud.com/40-55-series-tech/118664-speedo-gear.html
New Member - https://forum.ih8mud.com/40-55-series-tech/180628-new-member.html
Here are a couple links I posted info on part numbers gears and what gears will match the drive gears.
2 drive gears 4 plastic gear option. Not all can be mixed and matched.
Old threads below for sure. 2006 2007. I’ve been hanging around ih8mud way too long. lol.
Links to threads.
Speedo gear - https://forum.ih8mud.com/40-55-series-tech/118664-speedo-gear.html
New Member - https://forum.ih8mud.com/40-55-series-tech/180628-new-member.html
