Is there any way to tell the difference between the two, while its still under the car?
Thanks

 

I cant speak for the t45 but the 3650 just has a tremec stamp on it underneath. are you looking for the trans in your car?

mid 2001+ is 3650
01-below is t45

 

Yeh, Im looking for my car. I believe the previous owner of my car put a t45 in it, and I believe thats why my speedo is fast. I wanted to make sure, so I know what I need to get, in order to correct it.

 

Previous owner may have put gears in the car. I doubt transmition was swapped.

 

Ok I just drove my car down the rode and back, and at 2000rpm my speedo says Im going 75, but Im acctually doing 70. Anyone got an I idea of what gear ratio would cause this.

 

Jack your rear end up and mark the driveshaft to where you can see it take one complete spin. Spin your rear tire one full time and watch how many times the driveshaft will spin

Stock is 3.27 you youll see the driveshaft spin about 3.27 times if those are the gears. Other common ones are 3.55s, 3.73s, 3.90s, 4.10s, and 4.30s.

 

You can tell what kind of Trans you have in your car many ways.

For example:

Water Pump Pulley:
Short Pulley = 3650
Long Pulley = 45

OR

You can look at your door sticker. Its listed in there as well...

Look underneath the Vin for the TR code...decode it as follows:

Transmission

A 5 character value; the first character indicates transmission type, characters 2-5 indicate spring type, Front/Rear.

Transmission Codes
Code Model
P AODE
T AOD
2 (5.0L) M5OD
5 Five-speed manual, T5OD
6 Five-speed manual, T45OD
U Four-speed automatic (4R70W)
K Five-speed manual, Tremec TR-3650

Anything else you might want to know about that tag is here (94-04)
http://web.tampabay.rr.com/theflock/...doorplate.html

 

How do you know your doing 75? If your doing 70 then you have a 3.27:1 Ratio, which is stock.

 

I got one of my friends to pull beside me. his truck was going 70 my speedo said 75. I've had people do this a few times to make sure it was 5 fast.

 

That is untrue, because I have the short pulley, but I have a t-45

 

There were a few that I have seen that were off, i.e. T-45 w/ short pulley. The majority of the cars with 3650's have short pumps though.

 

The code on the door as mentioned before is a good way to ID the tranny. Also a T-3650 has a drain plug on the bottom where a T-45's is on the side



Jay

 

Cool, tomorrow I'm going to check for the drain plug thing, and check the drive shaft to see what gears I have. Maybe I will find out why my speedo is off.

 

Ditto - short + T45