TH400 Whining...
 

So, I just serviced the filter and fluid on the Th400 I have in my 64, and it has started whining when it's cold out.

After it warms up, or I drive it for about a mile or two, the whining goes away.

The filter and fluid are both brand new, and when I changed the fluid, there wasn't any real sediment in the pan.

I'm thinking front pump, but Im not too educated in this transmission to make any kind of diagnostic.

I do have a cooler on it, and the hoses are new(er) too.

Any help?

Re: TH400 Whining...
 

If it happened right after the filter change?

Double check the fluid level.
Check the plastic pick-up tube for cracks.
Check the O-ring the fits over the pick-up tube.
If no issues are found....Switch filter brands (Filtran make good ones).

Re: TH400 Whining...
 

Ok...ANOTHER update.

My truck has been sitting for the last 4 and a half months due to a BAD engine oil leak.

Two days ago, I got down to fixing the oil leak and went to pull the truck out from under my carport. There was some SERIOUS whining from the trans when I got it to fire up.

I tried shifting into gear, but there were no gears to be had.

At first, I thought that I had lost all the fluid from the trans, but further inspection told me that there was PLENTY of fluid in the pan.

Yesterday, after letting it idle for a minute or two, the whining started to go away, and I had gears again. I took it for a drive today around town and it's now driving just fine, albeit thought I do have a whine if I manually shift into first to take off.


Is it time to consider a swap or rebuild? Is this a case of the front pump going out?
I have a lead on a 350/700r4 from a late 80s van, and it makes sense to upgrade, but if I can keep this trans alive as long as I can, that would be awesome. (I've got a weird emotional attachment to it as it came out of my dad's 71 Monte Carlo )

Thanks guys.

Re: TH400 Whining...
 

It's been a year since the first post but did you do any of the checks that clinebarger mentioned?

Re: TH400 Whining...
 

Yes. Used a WIX filter, checked the old filter for damage, but nothing presented itself. The fluid level is normal at hot and it's even SLIGHTLY overfilled due to a small pan leak.
We are talking 1/8th" over full mark.

Re: TH400 Whining...
 

Sounds like your pump is getting very weak, Along with converter drain-back from worn Stator Bushings/PR valve.
If you have emotional attachments to the unit......Have it rebuilt or build it yourself, Installing a used/unknown 700R4 rarely works out.