I am guessing from your description that my L48 has a "350" trans. The car just turned 20,000 original miles last month, so everything must be stock. What I meant by wiggling is that if I am under the car and I take hold of the speedometer cable near where it attaches to the side of the trans & that the gear and cable does move up and down, not a lot, but I thought it should be tight and not move at all. I am concerned that maybe I should not be driving the car with it in that (what I call) loose condition . There is a small drip of fluid that comes out between the speedometer coupler nut  and the  speedometer cable housing. Plus I was wondering if this is going to be an expensive repair. I thank everyone for their assistance and input.

If your trans has the small, bullet type housing, they can be a little loose...not really much to hold them tight. There are two seals...an o-ring around the outside of the bullet, and the seal that seals the gear itself. You can loosen the 7/16" bolt that holds the small tab/bracket on, and let it flop down. Then, the bullet will pull right out. You might loose a couple of drops of fluid... not much, but have a drain pan, or something to catch what does drip out. 

Thank you so much for your input but I will ask one more question. Could you resend the photos you stated to have sent? I would really appreciate it or send it to my e-mail at itsonlywarm4me@socantel.net. Again thank you for your time and input. It is appreciated.

Hi again, OK so I finally got around to changing out the gear.

Only thing you CAN do, Joe...change the diff ratio......  

Just kiddin!
You cannot go any further with the gear changes unless you remove the trans, and change the DRIVE gear...you would need to have a drive gear with fewer teeth, and a driven gear with more teeth. However....does your trans still have the 90 degree adapter on the speedo cable, at the trans? It should have one, but if it does not, you need to get one that will slow the speedo down. Those 90 degree adapters are not simply 90 degree adapters...they also change the in/out RATIO, so the speedo will read correctly. It's much easier to spec an adapter than stock 10 different transmissions with different speedo gears, so GM used the adapters. If you DO have the adapter, then it's as easy as finding out what ratio it is, and getting one with a different ratio. The adapters are all stamped with the ratio on them, close to where the cable screws on. If no ratio change was need for that particular engine/trans/diff combo, the adapter would say "1:1". If it was a ratio change, it would read something like ".42".
btw...this info is ONLY for the 4 speed cars....the automatics did not use the 90 deg ratio adapter.

The adapter looks similar to this one....



|UPDATED|8/12/2013 10:20:26 AM (AZT)|/UPDATED|

Joel, thanks.

Not sure who would have them, Joe, but they are available. I know of at least one place that can custom make one any ratio you need. If you take a look at the speedo chart Larry posted above, you'll notice in the far right column it says "Adapter", and will list the part number needed for that particular gear/tire ratio, to make the speedo correct. Doesn't really apply to you, but just wanted to point out that they were factory installed in certain circumstances.
I'll see if I can dig up the info on the place I'm tinkin aboot, and post it here. The last 700 swap I built for a local guy needed one, and he had one made....I'll see can I find the info.

Joel, Thanks.

Joe, I think this is the place my buddy got his adapter, but not 100% sure. They DO have some NOS Gm adapters in stock, and can build a different type(not 90 degree) if needed. Might give them a shout and see if they can help ya.


APT Instruments

They also show how to Check the Ratio 


|UPDATED|8/13/2013 11:47:36 AM (AZT)|/UPDATED|

AWESOME! THANKS!