tranny speedo gear swap

[ReedZ]

Does anyone know if i can swap the little gear box from my 2.8L tranny with the one in the TH350.

I just got my swap done and my speedo is way out.

Will the 2.8l one fit right in, or do i have to get a special one??

[Jeffyboy]

I don\'t know for sure, but most of the time, speedo cables are universal, so there\'s probably a good chance it\'ll fit. Can\'t hurt to try!



Jeff

[ReedZ]

Actually, I was thinking a bit more about it, and i don\'t think it is the gear on the transmission.

Could it be that my stock rear end gears are too low for my tranny.

My old set up was 2.8L 4 speed manual.

i don\'t know what gears are in there. there is no decal on my glovebox, so i can\'t check the code.

The car the tranny came out of had 2:42 in it.

Can someone help me out with my problem here. i\'m not sure where i should start, or what i need to try to fix here.

[akajoker]

If you speedo is off, it\'s your speedo drive gear located in the tailshaft of the tranny, your speedo cable is probably fine, and it will fit in the turbo 350 tranny, but the gear in the tranny housing needs to be changed.

[FordWizKid]

Anybody have any ideas on being able to use a mechanical speedometer with a NV3500 ? Swapping out the electronic sender for a mechanical one ???

[ReedZ]

On 2004-05-03 21:40, akajoker wrote:

If you speedo is off, it\'s your speedo drive gear located in the tailshaft of the tranny, your speedo cable is probably fine, and it will fit in the turbo 350 tranny, but the gear in the tranny housing needs to be changed.





Where would I get a new gear for the tranny housing? How do I know which one to get?



Thanks

[ReedZ]

I meant to also ask if i could use the gear out of my old 2.8l v6 tranny? Would it fit into the th350?



Thanks,

[ReedZ]

Anyone??

[gdmclnh]

TCI transmissions web site has a very complete section about speedo gear calibrating. They even have a calculator to tell you what gear you need and have the GM part numbers for the gears. You need to know tire height (with the weight of the truck on them, properly inflated), the rear gear ratio and the number of teeth on the gear in the transmission tailshaft. This is the driving gear on the output shaft of the trans, not the gear being driven that turns the cable. The gears are color coded for the different number of teeth. Just determine what combination of gears you need from the calculator and take the Part No. to GM dealer and get the gear(s) you need.