In the last few weeks, I've had problems transferring/withdrawing LTC from exchanges such as Huobi Binance and Yobit to name a few, to Coinbase/GDAX. The problem is that these exchanges have not upgraded their litecoin wallets. If you're also having this problem, I've found a fix at https://litecoin-project.github.io/p2sh-convert.
Just copy you address from gdax, which should start with a "M" and goto https://litecoin-project.github.io/p2sh-convert and paste the address from gdax into field that say "P2SH Value:" and click convert. Then copy the address provided, which should start with a "3". Use the copied address to send to and you're done...
I made a post about this same issue a while back. Nano Ledger to GDAX suffers from similar problems. Check out this step-by-step guide too if you need some more guidance.
https://steemit.com/litecoin/@statistician/how-to-send-litecoin-ltc-from-nano-ledger-wallet-to-coinbase