Engine or Transmission Swap?

[iowa_hick]

A couple months ago, I found a 2003 4.0L Automatic with 150k on it that had just had a new transmission installed (they gave me documentation to prove it), but had a blown head gasket. The engine still runs, but it was blowing white smoke out the tail pipe, idles really rough, and runs out of water and overheats if you drive it more than a few miles. I got it bought for $800.

I started off by putting some Prestone Head Gasket Repair in the radiator bottle and following the procedure. It definitely helped the truck as the white smoke went away, but I'm still getting cylinder pressure into the coolant system and it still idles rough. I may try another bottle just to see what happens, but I suspect that the head gasket is too bad for a quick fix.

I watched a youtube video on removing the heads for the 4.0L and decided if I have to pull the engine anyway, it's not worth fixing this engine.

The Explorer itself is nothing special, a XLT in decent shape. I bought it mainly for the new transmission. My question is for those who have replaced engines and transmissions in these vehicles. Which is easier?

I basically have three options: 1) Buy a junk yard engine and put it in this Explorer, 2) Buy another Explorer with a bad transmission and put then engine in this one, or 3) Buy another Explorer with a bad transmission and put this transmission in that one.

What would you recommend? Do you have any suggestions for another option that I haven't thought of?

Thanks for the help!
Jaeke

 

[94Eddie]

IMO, it will be a lot less work to remove and install a transmission than an engine. So I recommend Option #3. This might give you an opportunity to buy an Explorer with a V8 that has a bad transmission. Then you would have a vehicle with a good transmission and a very reliable engine that should serve you for many, many miles.

 

[iowa_hick]

IMO, it will be a lot less work to remove and install a transmission than an engine. So I recommend Option #3. This might give you an opportunity to buy an Explorer with a V8 that has a bad transmission. Then you would have a vehicle with a good transmission and a very reliable engine that should serve you for many, many miles.

My daily driver is an '02 Eddie Bauer with the 4.6l, so I'm definitely a fan of that engine. I knew that both engines used the same transmission, but are the transmissions configured the same for both? Will this transmission just drop into a 4.6l or would I have to change some things to make it work?

Thanks!
Jake

 

[94Eddie]

You will probably have to swap the bell housing and a few other items but I think it is a straightforward swap. Others might chime in with more information.

 

[imp]

You will probably have to swap the bell housing and a few other items but I think it is a straightforward swap. Others might chime in with more information.

How does one swap a bell housing on a transmission having an integral bell housing of the wrong fit?

 

[94Eddie]

How does one swap a bell housing on a transmission having an integral b ell housing of the wrong fit?

Good point. I spaced that the 5R55 is a one piece design. Maybe a parts swap from the good transmission to the bad one? This would complicate things at the least.

 

[imp]

Good point. I spaced that the 5R55 is a one piece design. Maybe a parts swap from the good transmission to the bad one? This would complicate things at the least.

Maybe, but only a highly experienced builder can answer positively. One of the most critical specs in auto transmissions is the spacing of internal assemblies with respect to each other. This is accomplished by a series of thrust bearings and spacers, to ensure line-up of the holes in shafts which conduct fluid to the clutches. A broken or well-worn thrust bearing can stop a transmission from functioning. These bearings vary in thickness from transmission to transmission; some are selectively fit.

 

[07gtman]

First off you may have antifreeze in the oil and oil in you antifreeze, may want to check these first. since you put the stop leak in... the head gasket may be from overheating, the 4th option is to get a head from the junk yard and a new head gasket, put the new head and gasket in replace all the spark plugs change the oil and antifreeze fire it up....