E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: culp71 on May 16, 2018, 07:42:12 AM

Title: 727 speedo gear install
Post by: culp71 on May 16, 2018, 07:42:12 AM
I pulled out the plug that was in my 727 speedo cable area, from when I rebuilt it as at the time I didn't have the speedo gear, or housing.
now I do, what is the order and how does all install using proper seal, o ring, clip etc?

some "layouts" I find show the seal below housing others above and both have it two different directions...
Title: Re: 727 speedo gear install
Post by: Burdar on May 16, 2018, 08:51:55 AM
The large orange o-ring goes around the housing to seal it to the trans case.  The small black o-ring goes inside the housing and seals the speedo gear to the housing.  The o-ring installs from the outside.  The clip goes in AFTER the seal is in.

I like to put a little trans fluid on the gear shaft before installing it into the housing.

When installing the housing into the trans case, you'll see some #s cast into the housing.  This corresponds to the # of teeth on the speedo gear.  This is how you determine how to orient the housing in the case.
Title: Re: 727 speedo gear install
Post by: 1 Wild R/T on May 16, 2018, 08:54:23 AM
The black seal goes in from the threaded end with the lip facing down.... The ring retains it.... The O ring should be self explanatory...  When installing the adapter in the trans you need to align it based on the gear tooth count, it should match up with one of three groups stamped into the adapter....  That group needs to align with the index mark on the tail housing...
Title: Re: 727 speedo gear install
Post by: culp71 on May 16, 2018, 09:03:56 AM
so this would be correct
Title: Re: 727 speedo gear install
Post by: 1 Wild R/T on May 16, 2018, 09:30:12 AM
Quote from: culp71 on May 16, 2018, 09:03:56 AM
so this would be correct

It's from the service manual, why would you question it?
Title: Re: 727 speedo gear install
Post by: culp71 on May 16, 2018, 11:24:13 AM
didn't know if it was correct was simply a google search but I also found this one too...why I was confused
Title: Re: 727 speedo gear install
Post by: BIGSHCLUNK on May 16, 2018, 11:53:18 AM
GO WITH YOUR FIRST PIC   :bradsthumb:
Title: Re: 727 speedo gear install
Post by: 1 Wild R/T on May 16, 2018, 11:54:40 AM
Quote from: culp71 on May 16, 2018, 11:24:13 AM
didn't know if it was correct was simply a google search but I also found this one too...why I was confused

Wow... Looks like a service manual photo but good luck trying to make that work.... Crazy...  I see your point.. 
Title: Re: 727 speedo gear install
Post by: RUNCHARGER on May 16, 2018, 07:23:26 PM
Second example is the Chinese-Fiat version.
Title: Re: 727 speedo gear install
Post by: blown motor on September 13, 2019, 08:09:31 AM
I assume the transmission needs to be drained to do this. Correct?
Title: Re: 727 speedo gear install
Post by: Burdar on September 13, 2019, 08:27:15 AM
No need to drain the trans.  A little fluid will come out but not a lot.  Put a pan under the speedo housing as you remove it.
Title: Re: 727 speedo gear install
Post by: blown motor on September 13, 2019, 08:33:59 AM
Can I just slide the old gear out and the new one in without removing the retaining ring and seal?
Title: Re: 727 speedo gear install
Post by: Burdar on September 13, 2019, 09:04:45 AM
Yes, the gear will pull right out of the housing.  Make sure you look at the numbers on the side of the housing and get it in the correct orientation when you reinstall it.  Depending on what gear is in it now, and what gear you are replacing it with, you might have to index the housing to a different spot.