Aight here is what I am having trouble figuring out. I just sold my 1989 Rs V6 camaro with 3.42 rear gears and with a T-5 BW, and I baught me a 1991 Rs V6 with 3.42 rear gears and has a T-5 BW. Now what boggles me is that the 1991 tops out at 110mph in 5th gear, where as the 1989 topped out at 130-135 in 4th and never had the ***** to see where it stopped at in 5th except i know that at 4,000rpms is 135-140 in 5th according to my old GPS. IS there a possability that the gear ratios in the 1989 v6 camaro T5 where different that the 1991.
1989 Rear gear code: 6HL 3.42 std
1st: 30mph 6,000rpm
2nd: 55-65mph 6,000rpm
3rd: 90-95mph 6,000rpm
4th: 130-135mp 6,000rpm
5th: N/A

1991 Rear gear code: 8HL 3.42 std
1st: N/A
2nd: N/A
3rd: N/A
4th: 85-95mph 6,000rpm
5th: 110mph 5,500rpm (shuts off rev limit)

If the ratios in the trans are NOT different then the only thing i can think of is that the splines in the Diff have been changed at some point. Cause with all the calculators that im finding on google it has a 3.42 gear but my TRANS 5th gear is 1.00 instead of the .94 or .74 or .64 that the 89 camaro had.

Any help with this mid boggling situation to ease my mind would be great.
Thank you.

 

There are two different T5's with slightly different gearing (1st and 5th gears). Models on a TBI engine have a .63 5th gear, and with a TPI engine, a .74 5th gear. But that's not nearly much of a difference to give you the swing you have. Plus 4th gear with both models are 1:00. If you're only going by the casting numbers to determine your rearend gearing, I'd say the gears in the ones in the 91 have been changed to a lower ratio, more like 4.11's. This is assuming your speedometer is accurate, based on the gears on the VSS on the trans. If that wasn't changed to recalibrate the speedo to match the rear gears, your speedo is lying to you. Have you tried having someone pace you with a car you know is reading right, to make sure you're really going the speed you think you are?

 

Thats the thing i use a gps and my buddies 2001 Pontiac Trans Am to get my MPH. I mainly go by my gps and my RPM Gauge, Since my spedo doesnt work. The thing that bugs me is it TOP out in RPMs at 5500 in 5th where as in my 1989 Rs Camaro i didnt have the power to even push past 4500rpm in 5th. All i can think of is the code on the rear end is saying 3.42 gears but someone has possibly changed the spider gears to a higher ratio.

 

Your gears in the 91 being changed to a lower ratio (higher numerical) is what I was suggesting earlier.
Btw, it's not the spider gears, it's the ring & pinion gears that get changed.

 

Thank you for correcting me "Ring and Pinion" i was in a hurry to get out the door for work when i posted. I finally got a hold of my uncles at Glovers Garage and told them what i was so puzzled about. They said the T5 came with various Ratios and said they thought that the trans ratios where my main cause. We tested the ring and pinion earlier today with the white chalk mark and turn the tire test and count the revolutions. The Axle is correct 3.42. My next step is to try and search the serial numbers on the Trans. Im not the brightest crayon in the box, but i like to know everything about my car. I have only had the car about 2 months. The 1989 I have for 6 or 7 years, it was all original when i bought it from the original owners and it was all original the day i sold it.(except for the hood)

 

Let us know what you find out about your transmission.

 

All i have found out is that the car has a World Class Transmission the trans serial is 1352-197 when i looked it up it claims to have been from a 1989 v6 camaro. All i can think of is that it was manufactured in 1989 they finished using up stock til the early to late 90's. My Diff is a 3.42 gear ratio. I have also recently found out that most if not all the RPM gauges from 90-92 where always reading to high. So more than likely my RPM gauge is reading higher than the motor and actually turning, cause i can take the rpm gauge to 7k and the car want shut off. It just keeps pulling. Anyways its not to much of a both. Im going to get me a multimeter that measures RPMs and correct the gauge with a some resistors.

 

Aight last night August 19, 2012 i took the board out of the cluster that controls the Tach Gauge, there is a lil black and white resistor chip on the board. I followed a thread on another forum and measured my resistance.

My resistance between pins 4 and 10 was 299-300. The actual resistance should be around 200 give or take,. I purchased a Actron Multimeter that reads engine RPMs and pluged up the RED lead to the DIST and the BLACK lead to the body. I also purchased a potentiometer 1meg ohm. Soldered to pins 4 and 10 on the chip, then matched the resistance that the tach needed to match as close to the Actron device as possible. 200rpm on the actron is 2,000rpm.

In all i have learned that sometimes whats wrong with the car is just a loose nut behind the wheel that can't leave anything alone lol. here are some pictures maybe this will help others out.

 

I have a nice looking red 89 IROC Z28 vert but has chronic alternator problem.

Some say it could be ground problem but where??

 

My guess would be probably the ground from the battery to the body. If all else fails take you car to the nearest Advance Auto, or Auto Zone and have them test your battery to see if it needs to be replaced. A bad battery will cause all sorts of alternator problems. Worn out pulleys such as tensioner pulley, idler pulley or even the water pump bearing could be dragging behind causeing a strain on the alternator, the most commom problem is alternator bearings.