Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Typical RPM and Torques for an Automatic Transmission

Typical RPM and Torques for an Automatic Transmission

Typical RPM and Torques for an Automatic Transmission

I am looking for RPM and Torque data for automatic transmissions. Can someone give me some typical values or point me in the right direction?

RE: Typical RPM and Torques for an Automatic Transmission

I don't really understand your question. Input rpm and torque values are engine output torque and engine values. Torque convertor output torque values are dependent on the characteristics of the TQ. Zero torque at zero engine rpm and max torque at whatever rpm the convertor locks up. I should add that this assumes no loses in the convertor and that older convertor never really completely lock up. I think they achieve about 95-99% lock up. I don't know if the new stuff truly locks up. The same type of analysis goes for the transmission itself...You make an assumption about how much slippage is occuring in the clutch packs. I hope this helps.

RE: Typical RPM and Torques for an Automatic Transmission

Our torque converter has a lockup clutch, which is electrically actuated as and when the strategy says to do so. It has a limited heat capacity, so you don't use it during full throttle shifts, although once it is engaged it can easily handle the full engine torque. It does not slip at all.

Typical 4 litre engine torque converter characteristics would give a maximum torque multiplication of two, at about 1800-2200 rpm.


Greg Locock

RE: Typical RPM and Torques for an Automatic Transmission

Generally for the use of Automatic Gearboxes with torque convertors on commercial Vehicles, the Transmission manufacutrer has a software programme to run and provide u with all details of power consumed, output torque developed, gear ratios, gear change RPMs, heat generated in the torque convertore which has be to added to the vehicle engine cooling system. generally the max. heat condition is considered at a convertor efficiency of 80%. Most Vehicle manufacturers design their cooling system for this value. Otherwise, the torque output from the transmission would then depend upon the demand the vehicle requires, based on load, gradient, acceleration, etc.

The subject is a very intricate one and there are persons who have completed PhDs on some of the parts of an Automatic GB. Suggest you word your question in more detail.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close