65 C10 Swapped 3 on the Tree to TH400 - Gearing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

65Oldred · 11-13-2023, 05:59 PM

Hello,

Awhile back we dropped in a "new" V8. While we had the truck apart, we replaced the 3 speed because it appeared to be shot (and it was) with a rebuilt TH400.

The gearing must be off. It drives like it could pull out a tree stump but seems constrained at highway speeds. (I believe the truck has the original rear end.)

Is the combination of a TH400 and gearing in the differential a problem?

Would going to a TH350 or 700R4 solve this problem?

Thanks.

11-13-2023, 05:59 PM	#1
65Oldred Registered User Join Date: Nov 2018 Location: Long Beach, CA Posts: 33	65 C10 Swapped 3 on the Tree to TH400 - Gearing Hello, Awhile back we dropped in a "new" V8. While we had the truck apart, we replaced the 3 speed because it appeared to be shot (and it was) with a rebuilt TH400. The gearing must be off. It drives like it could pull out a tree stump but seems constrained at highway speeds. (I believe the truck has the original rear end.) Is the combination of a TH400 and gearing in the differential a problem? Would going to a TH350 or 700R4 solve this problem? Thanks.



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