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**Accelo** · 03-14-2022, 02:16 AM

A one-piece driveline works fine on a short box. Something to consider is they made the THM350s in three different tail shaft lengths. Your truck would have had a short tails shaft (6") from the factory. If your transmission tail shaft is longer the driveline is shorter and less likely to whip. I am confident that was the exact reason for the extended length on some of the 350-transmissions. They were up to 12" long.

Unless I had a THM350 on the floor I would consider installing a 7004R or what is now called a 4L60. It also has a longer case which will shorten the drive-line overall length. Although it is not much, less than 3". Comes with the added benefit of lower cabin noise and up to 30% better mileage.

03-14-2022, 02:16 AM	#4
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,356	Re: Driveline question A one-piece driveline works fine on a short box. Something to consider is they made the THM350s in three different tail shaft lengths. Your truck would have had a short tails shaft (6") from the factory. If your transmission tail shaft is longer the driveline is shorter and less likely to whip. I am confident that was the exact reason for the extended length on some of the 350-transmissions. They were up to 12" long. Unless I had a THM350 on the floor I would consider installing a 7004R or what is now called a 4L60. It also has a longer case which will shorten the drive-line overall length. Although it is not much, less than 3". Comes with the added benefit of lower cabin noise and up to 30% better mileage.