I changed my tranny today. It came out of an 88 trans am, I am assuming it had TPI. I have an 88 firebird with TBI. Now the speedometer is around 10MPH off. Is that because of the different speedo gears or something else? And is there a way I can fix it. Thanks

 

Speedo gears. The rear left side either a 2 pin plug or cable driven. Remove the bolt and attachment holder and pull out the speedo assembly. Rotate and pull. The Drive gear is on the tailshaft and only removable by removing the tailhousing. But there were only a few different ones of those. Look in there to see its color. Gray was most common and 15 teeth. Also check to see what Driven gear is. Its on the part you removed. Those are color coded as well. Youll need to lookup a site with a gear ID and a calculator. You will need to know Trie Height and Gear Ratio. Try getting a Driven gear to match up with your current Drive gear. That will save you time and money replacing that one. Dealer has the gears and so does some sites

 

Oh wait, I quess i dont have a speedo gear,I that sometying esle. I just have too electical plugs. I dont know what i was thinking. Is something else that could cause my speedometer to be off. Im sure it was accurate before i changed the tranny.Thanks

 

No, its got speedo gears. The speedo can be electrical or cable driven. Most F-bodies (and your 88 is) electrical. The 2-pin/2-wire plug on the left rear is your speedo sender. There is gears in there and the sender converts to an electrical signal. Ive seen devices you can 'wire in' to adjust the signal to correct the speedo. Or you can just figure out the gears needed.

 

Could I just take the ones out of the old transmission?

 

If they were the same trans.

TOM

 

There both 700r4's it was the transmission that came out of it

 

Then you are good to go .

TOM

 

X2

 

Alright, I'll do that. I do still have the same problem with this tranny as i did the original. I am thinking I need a new TV cable, which i did adjust. It feels like its shifting way to early at light throttle at 2nd and 3rd. And its kind of a long shift. Feels like a stick shift when you up shift to early. It drops and then takes a second and picks back up again. And if I keep it around 25 it feels like its shifting back and forth between gears. Thanks a lot I appreciate it.

 

Pull the governor too and check it. Round cover forward of the speedo sender on the left side. Once the cover is popped off pull the governor out with a slight rotation. Check the gear on the end for broken teeth. Then hold it with the gear facing upwards......the spring/weights should fall outward.....look in the slots on the shaft and you will see the spool valve in there.....push the bottom spring/weights inward and verify the spool valve inside is operating freely. If not clean with mineral spirits and blow dry. Try again. If the gear is broken you can replace it. Reinstall the same way it came out. Seat the cover good and there is a o-ring gasket on it. The TV info you can find here http://www.tvmadeez.com/article/index.php Top left is 2 more pages of info and instructions.

 

Thanks again for all the info. I did have another thought. I have been getting a code 32 (EGR). Could that make the car surge at light throttle, and i just might be mistaking it for the tranny shifting wierd. I took the car for a drive earlier and i noticed it does feel more like surging. I got to thinking, the cars does it two or three times before its even time to shift. which brings up another question, what rpms is it supposed to shift at light throttle. Also, it doesnt seem to happen at all when the engine is cold, only after a few minutes of driving will it start acting funny. Could it be the EGR???

 

EGR possibly could

 

Hey, thanks a lot. I am gonna move over to the TBI section, unless theres a better forum for EGR's someone can think of.
Thanks again