Jump to content

Transmission type for 2500 HD 4x4 8.1 gas


Recommended Posts

I recently purchased a 2001 2500 HD 4x4 with the 8.1 gas engine. While greasing the driveshaft, I noticed a spin on filter for the transmission and the words Alison on the tyranny pan.. It's a 4 speed automatic.. I thought Alison transmissions were either 5 or 6 speed.

Which model Alison transmission do I have?

Link to comment
Share on other sites

The Allison 1000 is a 5 speed transmission in 2001.

 

The 4L80e is a 4 speed transmission but those obviously won't say Allison on it and they don't have external transmission filters.

 

 

Link to comment
Share on other sites

So which transmission do I have? The shifter has the standard PRND321, and I have a tow/haul mode button on the end of the shifter. Is it a 5 speed, but I'm only using 4? I'll test drive it later and verify the shifts.

Link to comment
Share on other sites

13 hours ago, Denis S said:

So which transmission do I have? The shifter has the standard PRND321, and I have a tow/haul mode button on the end of the shifter. Is it a 5 speed, but I'm only using 4? I'll test drive it later and verify the shifts.

The 5-speed Allison has PRND321 on the shifter.  Press/hold the T/H button for a few seconds and you should get a D-with-slash on the cluster display, aka overdrive lockout.  Press/hold the T/H button for a few seconds to re-engage 5th.  They used this instead of a "4" on the shifter.

 

When you count shifts it may feel like it's a 6-speed, but one of them is the torque converter locking up.

Link to comment
Share on other sites

Thanks for the info. As you said, it's a 5-speed. I have 4 upshifts, at 2500 rpm, and then the torque convertor lockup. So it is the Alison 5-speed. I'll play around with the T/H mode to get familiar with that function.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.