02 international 4300 Allison Limp mode can’t drive

If in California leave asap that would explain it

 

That is not a trans code. It actually comes from the cluster for that specific code. The "p" means it's also an inactive code. What are you using to read codes?

 

We never recommend relying on dash displays for reading codes. You are right in that it is entering limp mode. Reading the codes with a proper scanner is so important, as you are finding out. This is your next step.

 

Heavyd knows much more about these than me but I will add this.
We had one with wiring to close to the exhaust near the bellhousing. That caused all kinds of problems over a long period before it was figured out.

 

This is a common issue, actually kudos for mentioning it.

I would get someone with the proper equipment and knowledge to read the code. I've been seeing more and more codes that require a decent amount of code/wiring tracing. I hope it's something much simpler for you as opposed to sinister.

Wish you luck!!

 

That sounds like a severely under filled trans