I've got a 64 Suburban with an original radio that works very well until the temp drops to about 40. This radio can be heard from a long way off. If I let the cab warmup to 70 or so it will just squeel for about a minute but much less volume? I had a local "radio guy" look at it but i don't think he knows a whole lot more than I, at least about this problem. Sounds like you have lots of experience with these older radios. Any help would be greatly appreciated. Thanks