4l80e torque rating in my 2500 burb doesn't make sense!?

Jonny5cam · January 29, 2015

So, my MT1 4l80 in my 2001 2500 burban is only rated for 440lbs max engine torque but my 8.1 is good for 455lbs and my gvwr is 19000lbs. The rpo code is MT1 and it's the original tranny. Did they upgrade the internals and just use the incorrect rpo code?

gmtech4 · January 29, 2015

So, my MT1 4l80 in my 2001 2500 burban is only rated for 440lbs max engine torque but my 8.1 is good for 455lbs and my gvwr is 19000lbs. The rpo code is MT1 and it's the original tranny. Did they upgrade the internals and just use the incorrect rpo code?

This is the strangest thread I've ever read ,

You're upset over BS specs of 15 lbs ?

Stop searching the Internet , it'll hurt your noodle ... Oh wait .... To late lol

Relax bud , don't over think this crap

Jonny5cam · January 29, 2015

I'm an engine guy, not a tranny guy so be nice. I saw the ratings on this forum and only then did I start hurting my noodle. Lol. Just wanted to know what I had.

Jonny5cam · January 29, 2015

And don't think it's strange to wonder why using a transmission with a max torque rating that's less than a mated engines' max torque rating. It just didn't fit in the parameters. And I never said I was upset.

oldscsc · January 29, 2015

You have a 4L85E, not a 4L80E. Same trans externally with the 85 having stronger internals.

Jonny5cam · January 29, 2015

Thanks man, that answered the question I was asking. Again, much appreciated.

fondupot · January 29, 2015

You have a 4L85E, not a 4L80E. Same trans externally with the 85 having stronger internals.

Bingo.

gmtech4 · January 30, 2015

Thanks man, that answered the question I was asking. Again, much appreciated.

All good ,

I was a tranny guy and never saw the specs you provided ,

Can I ask where you got them ?

We were told in tranny school that the torque rating was just a number assigned depending on capabilities , and it never showed the numbers you showed

Jonny5cam · January 30, 2015

CapitalTruck posted them on this forum in 2007, I've also seen these specs elsewhere. http://www.novak-adapt.com/knowledge/transmissions/automatic/4l80e.htm The main reasons for my questions were that the 4l85's rpo code is MN8 and my truck's rpo lists the trans as an MT1 for the 4l80. This didn't jive with the truck's 19000lb GVWR. And on top of every thing else I plan on putting a blower on this thing. I know the 14 bolt can handle it easily, just wanted to make sure all of the links in the chain were up to the task.

All good ,

I was a tranny guy and never saw the specs you provided ,

Can I ask where you got them ?

We were told in tranny school that the torque rating was just a number assigned depending on capabilities , and it never showed the numbers you showed

MikeNH · January 30, 2015

All good ,

I was a tranny guy and never saw the specs you provided ,

Can I ask where you got them ?

We were told in tranny school that the torque rating was just a number assigned depending on capabilities , and it never showed the numbers you showed

GM Powertrain's website has the specs. Not sure if they publish legacy part specs though, I think it's only current stuff.

chevrolet1616 · February 25, 2015

This is the meaning of the transmission naming scheme. ..

4L65e: 4 gears, longitudinal mounted, 650 ft lbs, electronic controlled

A 4L80e is rated to a maximum torque of 800 ft lbs from the engine.

This doesn't mean you can run that much torque, you will blow up the trans, it's a factor of safety built into the design it's why those transmissions have lasted so long in many GM products.

E.g 4T65e has the same gears and clutches as the 4L65e except the casing is different, so an impala basically has a truck transmission from a parts perspective

gmtech4 · February 26, 2015

This is the meaning of the transmission naming scheme. ..

4L65e: 4 gears, longitudinal mounted, 650 ft lbs, electronic controlled

A 4L80e is rated to a maximum torque of 800 ft lbs from the engine.

This doesn't mean you can run that much torque, you will blow up the trans, it's a factor of safety built into the design it's why those transmissions have lasted so long in many GM products.

E.g 4T65e has the same gears and clutches as the 4L65e except the casing is different, so an impala basically has a truck transmission from a parts perspective

It doesn't have the same parts at all , only the torque rating .... Sorry

chevrolet1616 · February 26, 2015

Ah ok misinformed

oldscsc · February 26, 2015

This is the meaning of the transmission naming scheme. ..

4L65e: 4 gears, longitudinal mounted, 650 ft lbs, electronic controlled

A 4L80e is rated to a maximum torque of 800 ft lbs from the engine.

This doesn't mean you can run that much torque, you will blow up the trans, it's a factor of safety built into the design it's why those transmissions have lasted so long in many GM products.

E.g 4T65e has the same gears and clutches as the 4L65e except the casing is different, so an impala basically has a truck transmission from a parts perspective

This is false information. The "60" in 4L60E is the strength rating on a rather arbitrary scale. It has nothing to do with the torque rating itself.

gmtech4 · February 26, 2015

This is the meaning of the transmission naming scheme. ..

4L65e: 4 gears, longitudinal mounted, 650 ft lbs, electronic controlled

A 4L80e is rated to a maximum torque of 800 ft lbs from the engine.

This doesn't mean you can run that much torque, you will blow up the trans, it's a factor of safety built into the design it's why those transmissions have lasted so long in many GM products.

E.g 4T65e has the same gears and clutches as the 4L65e except the casing is different, so an impala basically has a truck transmission from a parts perspective

Teachers never put it this way at GM transmission school , idk where you'd get this idea lol, nonsense