question fellas


Junior Member
fellas i looked under my 85 mint condition sierra classic last night and found the words hydromatic on the trans. pan. i also found that i have an th400 trans. hooked up to the plant under the hood. what is the hydromatic? also to double check is the th400 cast iron or alum.?
also i have a 10 bolt rear end. what kind of work will it do? and does anyone have the proper ohm readings on the temp sender, i want to check it for proper op. on my uncles truck. he has the same truck i do.


2000 Club Member
TH stands for Turbo Hydramatic, which is the tranny division of General Motors. The tranny is an aluminum case, I think you are confusing the transfer case issue with the aluminum vs cast iron. Far as I know all auto tranny housings are aluminum.
The 10 bolt rear is ok, but not the most desired unit if serious towing or hauling is to be performed or if you plan on adding larger tires and doing some off roading.