question on 400 tranny...

[bryguy00b]

first of my dads truck has (350/400/203) for drive train, 79 3/4 chevy)

my question is that the tranny seems to whine a lot when its cold..done it for a while..after a while it will go away when its warm..but if it sits for a couple hours or more in the cold you start it up and drive it..it whines really loud...any one know why it does that? it didnt use to...it still shifts fine and everything though...

 

[HarryH3]

Does it sound similar to a power steering pump going bad? If so, then it's most likely the front pump. I had a pump that whined slightly in my '87 K5. It whined a little when I bought it, with 66K miles on it, and still whined the same amount when I traded it in, with 125K miles on it. /forums/images/graemlins/cool.gif It never was very loud however... Certainly not enough to be objectionable.

 

[bryguy00b]

well i dont know what that sounds like..but my dad said that moight be the problem when he told me about it this mourning..he mentioned something about a front pump...all i know is it gets louder the faster you go...

 

[Longhorn4x4]

Change the fluid and filter. Use an Allison brass screen high flow filter. You'll have to go to a transmission parts house because you'll need pan gasket for a 400 turbo, but a filter for an Allison. Only a transmission parts house will have an Allison filter, or even know what you're talking about. Should solve the whining, usually caused by a restricted filter. Of course, if the pan is full of trash from wear, it won't fix that.

If it only whines when it is moving, it is possible that a bearing is bad. The 400 uses Torrington bearings in the geartrain, and sometimes they whine when they go bad. Only way to fix a bearing is to replace it. They usually whine the same whether hot or cold.

 

[bryguy00b]

no actually it whines while ideling now that i think of it....when you start it whens its really cold it will go on high idel with the automatic choke..then you have ot tap the gas and bring it bake to normal idel..and thne when you move and drive it still does it..louder the faster or higher the rpms...