As a rule, the ZF transmissions in DIIs are close to bulletproof. If you got 320,000 miles out of the trans it's served the truck well.

Some on this forum may have rebuilt transmissions on their own, but doing so is a relatively obscure and infrequent occurrence.

You haven't said where you are located, but installing a used trans is probably your path of least resistance.

There are many components most of us wouldn't buy used, but like I said, the ZF trannys are close to bulletproof. Just try to find one with substantially fewer miles on it than the one you are replacing.

 

I am located in Sydney Australia, do the ZF trans just bolt straight in?

 

The transmission in your truck is a ZF. Either the ZF4HP22 ('99-'02) or the ZF4HP24 ('03-'04). So yes, it's a direct replacement for what's in your truck. What year is your DII?

So since you're in Australia, is the "320k" you referenced kilometers or miles? Either way, it's done it's job.

Do you have the factory service manual, known as the RAVE? It describes the procedure for removing and replacing the transmission, differently for the petrol V8 and diesel variants. It's linked in my signature below.

 

In the US low mile Disco transmissions go for less than $300 US, not sure what they would be down under. Hard to believe it woudl be worth shipping it but you could check. I would think there would be several people breaking discos on Facebook in Australia where you could snag one. They are so reliable they usually last the life of the vehicle, usually the vehicle is wrecked or the engine gives up and leads to one being dismantled for parts first.

Good luck.

 

The k refer to kilometres and no I don’t have that. I will have to download it.