Hi guys. I just bought an '89 IROC 5.7 TPI with a 700R4. On the way home, I noticed the speedometer was reading about 10 MPH slow (in relation to trailing van speedo). The transmission has supposedly come out of an '89 Trans Am, but no info on engine size or gearing. Would it be pretty safe to assume that the trans speedo gear is the wrong size? Where can I find out the right one to use? Also, When I'm cruising at what i estimate to be about 45 or 50 the transmission will be in 4th. I drop the hammer and the transmission only drops to third. According to the tach, the RPM's only increase to 2,700 before shifting up. Is this how it's supposed to be? Could there have been some sort of screw up with the TV cable while installing the newer transmission? What do you guys think?

 

Just a bump. Can anyone help?

 

How does the car shift while driving in town? Is it only the drive to overdrive shift that is low?

 

The whole shifting sequence seems to be a little off. When accelerating slowly, the transmission seems to want to hang on to a gear for an extra 5-700 RPM's before shifting higher. Like I said before, if I manually drop to 2nd while hitting the gas at highway speeds the RPM's push up to about 4500 and it takes off like a rocket. I can then put it in OD and it acts 'normal'. But, if I just hit the gas the RPM's only jump to about 2700. The previous owner said there had been a TH-350 in the car from another owner, and he had it changed it back to a 700R4. I don't know if computer control was retained, but what about the possiblilty of them changing the EPROM to accomodate the 350? Isn't this responsible for the setting of the shift points?

 

check the TV cable for proper adjustment for the shifting problem. On your speedo problem, check out this website. http://www.tciauto.com/tech_info/speedo_gears.htm

 

That website rocks! Thanks for the link. I'll adjust the cable as soons as it stops raining, or if it stops raining.

 

No thanks is needed... only a small deposit to my paypal account lol