700r4 speedo port not spinning at all.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
can anyone send the link to a 29 tooth gear? preferably on amazon? or 30 tooth?
 

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
Help porfavor.
I can't find anything on this axle code. I just need the size or whatever. Ex: 2.75

Kdx 244w91
 

Attachments

  • 20240324_191918.jpg
    20240324_191918.jpg
    128.8 KB · Views: 41

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
So as it turns out I had it all wrong. I need a 44 tooth gear. Not a 29. My axle ratio was 4.10
 

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
Yea, the gears available in the aftermarket are color coded but you still need to know what color to buy which means you still need to count teeth on your originals than look up the tooth count by color on the replacement drive/driven gears so you purchase the right set for your vehicle. Also you dont need to stack seals, just replace the old one with a new one then the little retainer on top of the new seal.


So will I have to do anything else besides take out the little port thing, swap/replace the old seals and driven gear?
 

NickTransmissions

Supporting Member
Supporting Member
Joined
Aug 3, 2023
Posts
450
Reaction score
906
Location
Las Vegas
First Name
Nick
Truck Year
1987
Truck Model
R10
Engine Size
350
So will I have to do anything else besides take out the little port thing, swap/replace the old seals and driven gear?
Little port thing? Lol, are you working on a boat?

Kidding aside, simply remove the speedometer housing w/ driven gear and seal (dont lose the little retaining ring) then install the new driven gear, replace the seal if it hasnt been replaced already then bolt the assembly back in place in the extension housing.
 

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
Little port thing? Lol, are you working on a boat?

Kidding aside, simply remove the speedometer housing w/ driven gear and seal (dont lose the little retaining ring) then install the new driven gear, replace the seal if it hasnt been replaced already then bolt the assembly back in place in the extension housing.
Lol. It's common here to just say thingy or thingyamajiger!

Would this work for the seals?

I'm so glad I decided to check the diff and see what ratio it was. Also learned about what the ratios also do.
 

NickTransmissions

Supporting Member
Supporting Member
Joined
Aug 3, 2023
Posts
450
Reaction score
906
Location
Las Vegas
First Name
Nick
Truck Year
1987
Truck Model
R10
Engine Size
350
Could I get the same kit for a TH400 work? I can't get the 700r4 one in time but I don't see a difference between the 2.
Maybe - not sure to be honest...You'll have to research that question or maybe someone else will respond to confirm/deny
 

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
I went ahead and just orderd the part. Hopefully it will at least get here Monday. I'll just have to suck it up and crawl under the truck.
 

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
I ran into a issue. I orderd a 44 tooth gear and a new housing for it.
I counted 40 teeth on the old gear. It was stripped and bent a little.
The drove gear looked fine and also looked metal?
I tried to install the 44 tooth but it wouldn't go in. So like a idiot I had my freind spin the tire backwards. And it sucked the gear in and bent it.
I reached the conclusion that the driven gear must be for the smaller size.
I put the old gear in the new housing and re installed the truck and did other irrelevant stuff.

So do I need to order a 38 tooth ish gear? Along with new housing. I'm going to be puting bigger tires on it.

Now the other question is. The 40 tooth I had in there looked smaller than the 44 I had. Which by my reading they shouldn't.
I can't return the housing or the 44 tooth because they came together and 44 is damaged.
 

Attachments

  • Screenshot_20240415_223145_Gallery.jpg
    Screenshot_20240415_223145_Gallery.jpg
    22.9 KB · Views: 34

Wumbo

Full Access Member
Joined
Dec 12, 2018
Posts
1,084
Reaction score
3,997
Location
Illinois
First Name
Rob
Truck Year
1986
Truck Model
C20
Engine Size
454
Thats a reluctor for an electronic VSS.

You need to replace that with a mechanical speedo drive gear.

Look at the grey gear:

You must be registered for see images attach



You will also need the metal clip that holds the mechanical drive gear in place.
 
Last edited:

randomTruckKid

Full Access Member
Joined
Feb 26, 2024
Posts
159
Reaction score
108
Location
Rockport tx
First Name
Brian
Truck Year
79
Truck Model
C10
Engine Size
350
Thats a reluctor for an electronic VSS.

You need to replace that with a mechanical speedo drive gear.

Look at the grey gear:

You must be registered for see images attach



You will also need the metal clip that holds the mechanical drive gear in place.
Wait to this trans is suppost to be electronic?
If so that works out way better.
 

Wumbo

Full Access Member
Joined
Dec 12, 2018
Posts
1,084
Reaction score
3,997
Location
Illinois
First Name
Rob
Truck Year
1986
Truck Model
C20
Engine Size
454
Wait to this trans is suppost to be electronic?
If so that works out way better.
It can be either.

Install an electric VSS if you want to go that route, or you can remove the reluctor, install a mechanical drive gear and driven gear, and run a mechanical speedometer.
 

Latest posts

Forum statistics

Threads
44,416
Posts
957,114
Members
36,752
Latest member
78 squarebody
Top