I have an 88 350 3/4 ton suburban with an ailing 3spd. turbo 400 transmision. What all would be involved in the swap to a 4spd. overdrive 700r4? I no longer tow with it and would like the mileage benifits of the extra gear. I know half tons of this era were equiped with the auto 4spd. Are the transfer cases and related linkage the same? I am kind of hoping this is a bolt in deal.

well on a 4x4 i'm unsure i know the 700r4 has a different length to it but i'm not sure what all is involved i see it done but in reverse to how your doing it you will have to setup the kickdown cable on it since the 400 is electric kickdown

You will have to change the input gear to your transfer case. The t-cases that were behind th-350's and 700R4's have a 27 spline input and the t-cases behind th-400 & SM-465 have a 32 spline input. I'm not 100% sure, but you may also need a different trnasfer case adapter too.

Thanks for info guys. I really need to find a half ton equiped with a 700r4 and do some investigating. I don't really want to spend a fortune because my suburban is rusty. The trans. does have to come out and while it was out I thought I would upgrade. I really like this body style and don't really want to buy anything else at the moment. I might be better off finding a less rusty half ton with the 700r4 already in it.