I'm getting ready to pull the TH400 transmission in my '73 and replace it with a 4L60E. Found quite a few threads on the removal process but still have a few questions.

1) Should I drain the fluid first?

2) Dipstick/filler tube. Will I lose fluid through the opening once the filler tube has been removed if I don't drain the fluid first? Any tips or tricks on removing the filler tube? I do have some rubber plugs I could use to plug the opening if necessary.

3) Anyone use the Harbor Freight 800 lb low lift transmission jack and know how much clearance is needed for it under the car? Specs say it has an 8-1/2" minimum height. This jack: https://www.harborfreight.com/800-lb...ack-60234.html I have the car on wheel cribs now such that I have about 19" of clearance below the bottom of the frame rails. Just wondering if that is enough. I do have a QuickJack with SUV adapters I can use to raise the car a little higher if need be but I'm thinking this job will be a little easier with the QuickJack out of the way.

4) I picked up a set of Lisle transmission plugs to prevent fluid loss out of the tailshaft. The kit (#23400) came with the following plugs:
23410 (#1 size range 1" - 1.25")
23420 (#2 size range 1.3" - 1.55")
23430 (#3 size range 1.6" - 1.85")
23440 (#4 size range 1.925" - 2.180")

Anyone happen to know which plug fits the TH400?

5) I'll end up selling the transmission after I get this project finished. Are there any special storage requirements to make sure the transmission stays in good shape for the next guy?

Thanks,

DC

 

The fluid level will be right at the bottom of the trans case hole for the dipstick- any movement will splash fluid out- draining it is the only way to keep it from getting sloppy, and just draining it is a sloppy job. The torque converter will slide out if the trans gets a little nose (front end) down and drain even more fluid from there.
Your height is going to be close- I've pulled a bunch of GM's automatics on a simple floor jack and many times have to slide the trans off the jack to get it to clear the frame. Once in a while you can get it to come out from the front under the crossmember.
As far as storage, plug and cap everything you can.
Finally, watch you fingers-- the edges are sharp and the trans is heavy..

 

Thanks Tim,

Appreciate the help. I have a suction pump for fluid removal I can use to drain the pan so that's now part of the plan.

Sounds like the height will be enough to get the transmission removed and down as low as the jack will go. If necessary, I can then put the QuickJack back in place to gain what ever additional clearance I need.

DC

 

Just drop the pan to drain it.

 

Yes, you need to drain the fluid. As Derek stated, you drop the pan to drain the fluid. Then bolt the pan back on and drop the tranny.