TCCoA Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hello. I recently bought a 96 Ford Thunderbird with the 4.6L V8. The transmission shifts nice into all gears, but i've noticed when i'm cruising at 60 Mph the RPM's are somewhere between 1900 - 2100 rpm. I'm wondering, is that normal?
I've driven 91 Buick's before with a V6 and at 60 Mph when the torque converter lock up kicked in, i had RPM's around 1800.
It's my first V8, so i am not sure if its normal or not to have RPM's that high.
Does this transmission have a torque converter lock up? Where should the RPM's be at 60 Mph ? Or is what im describing completely normal?
Its my first Ford and especially my first V8 so i have absolutely no clue. I'd be very thankful for some help :)
 

·
Super Moderator
Joined
·
12,914 Posts
Perfectly normal. The 94 and 95 Tbirds have a stock final drive ratio of 3.08:1. The 96 and 97 cars were slightly higher at 3.27:1

with a 3:08:1 Rear End

4th Gear at 60 MPH rear end is 1,600 RPM
4th Gear at 63 MPH is 1,700 RPM

4th Gear at 60 MPH rear end is 1,600 RPM
4th Gear at 63 MPH is 1,700 RPM

What size tires do you have on the car?
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
Hello. Thank you for your reply. Im not really sute about gear ratios, but you're writing 60mph @ 1600rpm. Mine has 1900 - 2100rpm. Isnt that way higher?
I have the stock tire size: 225/60R16
Sincerely Jack
 

·
Super Moderator
Joined
·
12,914 Posts
Hello. Thank you for your reply. I'm not really sute about gear ratios, but you're writing 60mph @ 1600rpm. Mine has 1900 - 2100rpm. Isnt that way higher?
I have the stock tire size: 225/60R16
Sincerely Jack
I calculated that with smaller 215/70/15 tires and 3.08 rear end.

With 225/60/16 tires and a 3.27:1 rear end you'll be right were you're seeing the RPM at - 60 MPH at 2,000 RPM. Perfectly normal.

I believe the stall on the stock TC is 1,500 to 1,800 RPM.
 

·
Super Moderator
1997 Thunderbird 4.6, 1998 Mark VIII LSC
Joined
·
9,653 Posts
Don't put a ton of faith in the tach readout either. The needles from the factory were never particularly accurate. You can always throw a scan tool on there to see the actual RPM. Mine would show about 1800-1900 at 60 with the factory gear.

Changing the tire size without changing the speedo gear won't change the RPM shown on the tach for a given speed on the speedometer. It would affect GPS speed vs. tach RPM though.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #6
Hello :) Thank you very much for these answers. That definitely helped me a lot and i feel more comfortable now. I thought at first something could've been wrong with the transmission.

I have a different but real quick question, dont wanna open another thread for it.
When the engine is running, and the A/C controls are in Off position, i can hear a little hissing coming from that area. When i turn the engine off, it's hissing for a few more seconds and then stops.
Do i have a vacuum leak there? Is that a known issue and easy fix?
Sincerely Jack
 

·
Registered
Joined
·
400 Posts
You have a lot of vacuum lines connected to the right hand side selector switch. It's likely one of the lines may have come loose or broken. You would normally not hear any hissing from that area
 

·
Registered
1997 SPORT Laser Red. Restored May of 2020.
Joined
·
159 Posts
Hello there. If your tires are 225/60/R16, they are only stock tires if you have the SPORT OPTION. Check your door sticker for spring code JJJJ.
In my opinion, the 96 tbird with the sport option is one of the best 2-door cars every built. My '96 Sport, when stock, ran 2200 rpm at 77 mph and I often got 32mpg on a cool day with no headwind and no passengers. It may or may not have the OverDrive lockout on the shift lever--this was an option not always ordered by the dealer.
 
1 - 8 of 8 Posts
Top