If your turbo 350 won't downshift, try the adjustments and checks in this video. It is usually a matter of finetuning to get the downshift mechanism working properly. Downshift cables vary widely by application, so no links can be provided. Here are some tools and products that will be helpful:

3/8" Drive Socket Set https://amzn.to/3Fk99yH
Filter Kit (verify fit to your vehicle) https://amzn.to/3TLVMeK
Synthetic Transmission Fluid https://amzn.to/3TCVuqH

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