Black IROC 86

What do your RPMs hold at while cruisin down the freeway at normal speed like 70 or so? In OD my RPMs seem to be very high on the high way.

What is the shift point on an AutoMatic?

I Have a shift kit. I think something might be wrong with it but just askin questions to see whats up.

8Mike9

Depends on you rear gear ratio and tire size, could be from about 1700rpms to 2500+ rpms

1989GTATransAm

iTrader: (3)

Yep, with my 700R4 and 3.70 gears in the rear I'am turning 2500 RPM at 70MPH. Allen

Black IROC 86

I got stock gears I believe, on my 86 IROC. damn at 70 on the freeway ill be doin like 4500 which is ****in high and in OD it willl jump to the ****in red like at 6000 or some****.. and it seems to shift kinda high too. what you guys think is wrong? you think its something having to do with my shift kit? the last owner had it installed so i dont know what brand it is and if it is good or not.

vwdave

You sure its shifting into OD?

Hell, with 3.42's I am at 2250 at 70 (25.5" tall tires) and like, 3300-3500 in 3rd gear.

Morley

Your Tach is off.

MdFormula350

3.23 gears in overdrice at 60 mph alitle under 2,000 rpm.

Black IROC 86

How do i adjust it?

8Mike9

I don't think the tach is adjustable...someone may be able to calibrate it, but it'd probably cost more to have it done, than would be to install an aftermarket tach.

Just don't get one of those mombo-size ones that stick up on the dash board

rockind78

This may sound kinda dumb, but count the number of times your transmission shifts from the time you start in first gear. You should feel the transmission shift 3 times. If not, maybe you aren't in overdrive.

Z's r Best

my 86 IROC shifts at about 5500 rpm (305 TPI). I've been told the lower perf. engines shift at about 4500 rpm. I've seen a bad tach before. It seems to work right, it's just off on the high side. It's pretty simple to buy small cheap aftermarket tach and splice it into your tach wire at the distributor. If the tach in the dash is off it will even show up high at idle. We got another at the junkyard for $10 and it was off as well. The 2nd one from the junkyard worked and matched the after market tach rpm.