Original Trans?

[H/O84]

So I discovered today that my speedo is off and the odometer claims I have put on nearly 70 miles since I bought the car. I couldn't have put more than 30 miles on it. The car is an 84 Hurst olds so it has a 3.73 gear and a 200-4r. Is there any numbers on the trans to see if it is original to the car? It only has 38,3xx miles on it and a nearly new set of eagle gt tires. I know the car was bought by the PO in 2000 and parked soon after. I get the feeling it sat long before that due to the paint being very faded. The speedo housing is stuck but I think it has the a green gear in it when it should be blue. My current theory is the trans blew and it sat for along time and some one threw a random 200-4r in it. The speedo is not off by alot gauge say 35 and the car is actually at 30. Gauge says 30 car is going 25. Could it just be a gear is missing a tooth?

 

[TexasT]

Look on the pass side near the back of the trans for a tag like this one. What is on it?
Also the servo should have a cast number ending in 692.

 

[H/O84]

Thanks TexasT I was looking at the front because I thought I remembered hearing the tag was there. It has an oz trans as it should. I had the cluster out to fix the tac because it had a corroded junper and was reading like 6 cylinder gauge. Could I have messed up something when putting the cluster in? If a speedo gear is missing a tooth would it read high or low?

 

[L67ss]

All speedos are off a bit from the factory. And if you have a slightly diff size tire that'll throw it off even more. Actually I've seen cases where someone got a speeding ticket for 1-5 mph over and not only had the ticket thrown out but were able to successfully file harassment against the officer. I'm gonna say yours is prolly normal. How are you checking it?

 

[454GrandPrix]

All speedos are off a bit from the factory.

While this is sometimes the case, the most variance you typically see is 5% or less. However, the OP is claiming his speedo is off by at least 100%, which is just plain... loopy. He probably does have some issue with the transmission/speedo cable, but that is still an obscene amount of error.

For the record, there are free GPS speedo apps you can download. They come in handy to verify speedometer and odometer readings.

 

[L67ss]

5 mph off is well within the realm of factory error. As for the od I suspect either defective cluster or that the op had too much fun driving it and lost track of actual mileage

 

[454GrandPrix]

5 mph off is well within the realm of factory error.

It certainly is... if you're doing 100 MPH.

I suspect ... that the op had too much fun driving it and lost track of actual mileage

That's definitely plausible. I've done the same thing myself, many times.

 

[L67ss]

According to an ancient motortrend my brothers 88 camaro is 4 mph off

 

[H/O84]

I guess I could have lost track but I don't think I would have put 70 miles on it. Still working out issues on the car and most the driving has just been taking it around the block and one trip to the gas station. I may just let it be for now until I open the trans up

 

[L67ss]

Are you running stock size tires?