Incorrect Speedometer

BudW

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volare 77

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727 or 904 housing will work. I may have one but will have to check. As stated you will have to change the speedo cable and the gear too.
 

shadango

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Got under there yesterday and as folks have said its the "correct" style for this year......the clip type.

We didnt disassemble it, but there is red plastic showing ---does that indicate the gear in there is a red? Or is that just the housing itself?

We figured out that we have 2.76 gears and the tire height when on the ground is 25.25 inches tall....... the speedo reads about 5 mph low when driving at 25-45 or so........
 

volare 77

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The red housing has nothing to do with the color of the gears. You will have to remove the red housing to know for sure what gear is in there. Anything else would be a guess. I would get a new orings for re installation.
 

BudW

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The metal housing can be rotated to allow for the different diameter gears.

The plastic ones do not have quite the same capability. I have seen red and brown plastic (clip on) housings – color depends on the gear diameter.

The outer O-ring and inner seal/O-ring is highly recommended to replace (a common leak area).
BudW
 

shadango

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The metal housing can be rotated to allow for the different diameter gears.

The plastic ones do not have quite the same capability. I have seen red and brown plastic (clip on) housings – color depends on the gear diameter.

The outer O-ring and inner seal/O-ring is highly recommended to replace (a common leak area).
BudW
Are those orings available? Or is it a "see what you can find" deal? And where can I find the gears themselves? Assume the mopar speedo gear chart with the colors is accurate for all years not just the metal housings? Or is it different?
 

BudW

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The big O-ring is a more common size and most part stores will (generally) just give you the O-ring if you have old one with you.

The plastic / clip on housings also uses a smaller O-ring on the cable – again, easily matched up at a parts store.

The metal / screw on housing uses an inner seal that can be pushed out with a small screwdriver and pushed back in with a small deep socket along with its clip.

That seal can be obtained from a few different sources – but is not as easy as finding an O-ring.

From my ’77 parts book
Inner seal (O-ring) 2124328
Outer O-ring (1-35/64”) 6025752

From my ’70 parts book
Inner seal 2538588
Outer O-ring (1-35/64”) 6025752

Part 2124328 & 2538588 are no longer available from Chrysler – except as part of transmission gasket or overhaul set.
They can be bought on eBay, from transmission shops and other locations like that,

Part 6025752 got superseded to 6035709 (not rubber but a better material) and is $6.50 (US) from Chrysler.

Recently, I purchased a 3 piece seal set from a transmission shop, online, It cost me about 10$ (US) and came in a regular envelope. It has what I need to reseal either speedometer adaptor.

I do recommend adding a drop of ATF on the inner seal, before inserting the speedometer gear as well as liberally dosing the outer O-ring before installing (makes installation/removal a lot easier).
BudW
 

volare 77

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Metal housing and plastic housing have the same rotation setup for the gears. One metal housing is for 21-25 tooth and the other for 26-45 tooth. The plastic housings are the same way. 4028747 for 21-25 and 4028657 for 26-45 Also check the plastic housing for cracks. They seem to be more prone to leakage.
 
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shadango

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Recently, I purchased a 3 piece seal set from a transmission shop, online, It cost me about 10$ (US) and came in a regular envelope. It has what I need to reseal either speedometer adaptor.

Thanks Bud...I would like to go that route...do you still have the contact info for the online shop you ordered the kit from?
 

volare 77

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Only the large o-ring will work on the plastic housing. You would still need to find the small o-ring for the cable end. If the part number that BudW listed above is still available it would be cheaper to buy it from the dealer unless of coarse you could find one of those kits he was talking about from the trans place.
 
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volare 77

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shadango, conversation sent about the gear. Remember to consider the actual accuracy of the speedo itself as it may be off.
 

BudW

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Thanks Bud...I would like to go that route...do you still have the contact info for the online shop you ordered the kit from?
I “thought” I had purchased it from eBay – for I went through my purchase history (last 2 years) and found nothing.

Honestly, I do not know who I purchased it from.
BudW
 

BudW

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It says it is only for cars up to 75.....and if its for the metal housing only, it wont work for the plastic one?
The big O-ring will work. The seal/clip will not (on plastic housings ~ '76 and up).

I think the small O-ring can be obtained at any parts store from their O-ring collection.
BudW
 

shadango

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SO I am on rock auto and they seem to list the same small seal for the 80 as for the metal style housing......thats wrong.....grrrrrrr.

Glad I checked here first to know thats wrong....
 

BudW

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SO I am on rock auto and they seem to list the same small seal for the 80 as for the metal style housing......thats wrong.....grrrrrrr.
The web site might not be necessarily wrong.

Chrysler did the change over from Metal to plastic early in the ’76 production (December or January, ’76, not exactly sure). The early ’76 production cars were all metal (A, B, C & F bodies).

Chrysler had production supply issues with the plastic gears – so instead of halting the assembly line, they resorted back to the metal gears (note: I refer to metal gears as metal housing and metal stemmed gears) – all the way until even some new ‘79’s came new with metal gears.

It wasn’t planned to happen that way and is not reflected in any of the ’76 or newer part books, but I have seen a lot with metal gears in ’76 to ~ ’79’s cars.
I hadn’t seen an ’80 with metal gears yet (nor that many '79's) – but doesn’t mean some were made that way.
BudW
 

volare 77

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Or the plastic one was converted by previous owners. I did my volare back in the late 70`s when I couldn`t get the gear I wanted.
 

BudW

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FYI: pickups and vans (and many Jeeps) used the metal gear version until mid ‘90’s (no speedometer cable, just a sensor on end of housing – which sent signal to computer and speedometer, on the newer ones).
Pickups and vans never did use the plastic version. Some Jeeps might have used plastic– not 100% sure about them.
BudW
 

shadango

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The web site might not be necessarily wrong.

Chrysler did the change over from Metal to plastic early in the ’76 production (December or January, ’76, not exactly sure). The early ’76 production cars were all metal (A, B, C & F bodies).

Chrysler had production supply issues with the plastic gears – so instead of halting the assembly line, they resorted back to the metal gears (note: I refer to metal gears as metal housing and metal stemmed gears) – all the way until even some new ‘79’s came new with metal gears.

It wasn’t planned to happen that way and is not reflected in any of the ’76 or newer part books, but I have seen a lot with metal gears in ’76 to ~ ’79’s cars.
I hadn’t seen an ’80 with metal gears yet (nor that many '79's) – but doesn’t mean some were made that way.
BudW
So what model speedo cable would one use if switching from the plastic to metal housing?
 
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