old square shooter 636 engine (JD4039D)

Anybody ever pull the engine out of one of these? is there any decent way to do it with out pulling the boom off? This machine still runs (for now) but it over heated and blew the head gasket and now there is a ridiculous amount of blow-by so it wont last long. I got a price on a JD reman engine and I am just looking at what all is going to be involved in actually doing the swap.

Can you drop the rear axle and go out the bottom? The 1998 I worked on had the hydraulic tank in the rear and fuel tank in the middle so the bottom was open Getting that main boom pin out may prove to be very difficult at best,Does yours drive the hydraulic pump with a driveshaft off the front of the crank? If so it will probably be seized up. It has a set screw and keyway (if memory serves,it's been years) and those rubber couplings are usually bad on each end,and it took an air hammer and heat to get it to move. Terex lost the pages in the parts book for the couplings but they are made by a company named York and I found a York part number on the coupling and Terex took the number and sourced it somehow for us.

This ones a 95 vintage so yeah same set up. thanks for the heads up on the pump coupling. I was wondering about going out the bottom. that'll be an interesting exercise in geometry. that or find some way to keep the boom held up while I work. thanks again for the input.

I found my parts book and it looks like the axle mount is welded in so if that's
the case it has to come out the top. If you raise the boom all the way up is there room to get the motor out ? I ask because the boom cylinders may be in the way of getting something in there to lift the motor. You can't drop a cable down due to the boom and you need clearance to come in from the side with a forklift or hoist so look at all of that.You may not have any choice but to pull the boom. I don't know what facilities,tools or other equipment you have at your disposal to work with so that's a factor. You may need a lot of tools to get the pin out of the boom. I'll try to help any way i can. I've been doing this about 30 years so I've had experience with this. Just be safe-this stuff will hurt you if it goes bad.Good luck.

Should come out the top. Boom it up, pull the radiator, come back and out with it.