6.4 engine swap, donor motor checkout and prep?

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EriikK

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I am replacing a bad motor in a 2105 Ram 2500. For towing, not for higher power.
So we got the new motor out of the badly wrecked '14 2500. It has 69k miles on the clock.
It turns as it should with a wrench on the crank pulley.

My question is what would you replace or refresh or leave alone? I'm an experienced
mechanic but new to the Hemi.

Replace:
spark plugs, water pump, belt tensioners, what else?

I need to swap the oil pan anyway, so I can take a look at the bottom end, would you open up and look at rod and main bearings or just leave them alone?

I need to swap the front cover, so I can look at the timing chain etc while I am there. Leave it alone or refresh? Oil pump?

There is zero evidence of rear main seal leaking so I am inclined to leave the flex plate and seal alone. Or or would you change it?

Valve covers don't look like they are leaking, any reason to open them up?

Any particular common failure items I should replace while the engine is out?

Planning to use transmission, transfer case, intake manifold, wiring harness and sensors etc, all from my truck not the wreck.

This is a balanced budget kind of project. I can afford to replace things that will be likely to make this a more reliable long term tow vehicle. But I don't want to just replace everything in sight whether it needs it or not, nor do I want to open any cans of worms that I don't need to.

IMG_20221205_175221786.jpg
 

mtofell

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The 6.4 Hemi is generally reliable although I just got mine back from a (warranty) engine replacement at 8 years, 120K miles. I never completely understood what was wrong but I was getting misfire codes and the dealer told me there were metal shavings in some filter so they knew the engine was bad. I'd say you're statistically in a good position with an engine of that age unless it was damaged during the wreck.... which seems unlikely from your pics. I'd definitely save the (presumably) good tranny from the wreck for when yours goes bad :)
 
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EriikK

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(presumably) good tranny... heh. This was quite a wreck. The front axle was pushed back so far that the front driveshaft broke the transfer case in half. I thought the tranny would be ok, and it almost is. But there are some pieces of the case broken off. It would be almost OK to bolt in.. .but not quite. I was thinking to save it so I could rebuild it and swap it in later when needed. I've never done an auto trans rebuild, should be interesting. But I'd probably be better off buying a junkyard transmission with an undamaged case and combining them in the rebuild.

Are these transmissions generally reliable? I'm new to the Ram.
 

mtofell

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Are these transmissions generally reliable? I'm new to the Ram.
The second sentence definitely explains the first :) :) Honestly, it's the old saying about message boards only getting the problems and complaints. Are the trannys "generally" reliable? Sure.... are there many with problems? YES!! The 2014 with 120K miles I referenced above is on its third tranny.... well, same one I suppose but the dealer has opted to rebuild it twice under warranty. Having been on this board for the last 8 years since my truck was new I can tell you tranny problems were pretty scarce initially but have definitely been picking up in recent years and as these trucks age. And, for reference, the 66rfe is the tranny with the 6.4. The 68rfe is it's close cousin that is the standard tranny in the diesel version of our trucks. I say "cousin" because the 66 (gas) has the same ratios as the 68 (diesel) and it results in a pretty ****** towing experience (think low end torque for diesel). The 1-2 gap is a country-mile and sucks when towing heavy with the gas version. This is probably a good time of note the 66rfe (6spd) was replaced with an 8spd around 2019 and reports are it's a whole other (better) world towing. Reliability-wise the valve body seems to be the weak link n the 66rfe and there is a lot of discussion of aftermarket ones. As a guy with a warranty and no modern-day mechanic skills, a lot of this over my head so I just go to the revolving door at my dealer. I was kind of joking initially but all kidding aside I'd hang onto that tranny for parts if needed. I think swapping a valve body can be done on the truck and is pretty easy so at the first sign of problems that's probably your first course of action to rule out larger problems. Both of my failures I believe started with the valve body acting up.
 

Jeepwalker

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Was there coolant in it when you got it? I'd replace the common consumables (plugs/belts/PVC) and install it. If it's been 'dry' a long time, put a new Mopar water pump on. I'd probably only replace the lower radiator hose. IDT I'd pull the caps off, but you could. Some say don't disturb them. There are guys getting over 200k miles on these trucks now ..so they have the ability to last. My 5.7 has 172k.

You *might* want to pull off the exhaust manifolds (if these are prone to warping) and compare with a straight edge. Have them belt-sanded or machined if you detect warpage. Even if they aren't warped new exh gaskets can't hurt. Right now it's an easy job.

It might not hurt to hook up a battery and perform a compression test while you have one plug out of each cyl. But bear in mind that you'd be doing it 'cold' which is less reliable (so put a squirt of oil in each cylinder). But if the truck was wrecked pretty bad, the engine should be ok and presumably the compression good too.
 

Wild one

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(presumably) good tranny... heh. This was quite a wreck. The front axle was pushed back so far that the front driveshaft broke the transfer case in half. I thought the tranny would be ok, and it almost is. But there are some pieces of the case broken off. It would be almost OK to bolt in.. .but not quite. I was thinking to save it so I could rebuild it and swap it in later when needed. I've never done an auto trans rebuild, should be interesting. But I'd probably be better off buying a junkyard transmission with an undamaged case and combining them in the rebuild.

Are these transmissions generally reliable? I'm new to the Ram.
If it was in a hard hit accident,when you have the pan off,look the rods over as close as you can,to make sure they didn't bend ,especially if it was hit hard on the front end.Wouldn't be the first time i've seen rods bend from a bad accident.
 
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EriikK

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May i suggest, that while your engine bay is void of an engine
Flush your Radiator & Back Flush the HVAC System
Flushing the coolant system is a good idea. If in any doubt I will replace the radiator.
Do you also recommend flushing the AC system? Not quite so simple, and since it blows cold I am kinda hoping I can just move the components out of the way and not have to drain and refill the refrigerant. AFAIK it's not hard to service the AC with the motor in the truck, so no big incentive to do it now?
 
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EriikK

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Was there coolant in it when you got it? I'd replace the common consumables (plugs/belts/PVC) and install it. If it's been 'dry' a long time, put a new Mopar water pump on. I'd probably only replace the lower radiator hose. IDT I'd pull the caps off, but you could. Some say don't disturb them. There are guys getting over 200k miles on these trucks now ..so they have the ability to last. My 5.7 has 172k.

You *might* want to pull off the exhaust manifolds (if these are prone to warping) and compare with a straight edge. Have them belt-sanded or machined if you detect warpage. Even if they aren't warped new exh gaskets can't hurt. Right now it's an easy job.

It might not hurt to hook up a battery and perform a compression test while you have one plug out of each cyl. But bear in mind that you'd be doing it 'cold' which is less reliable (so put a squirt of oil in each cylinder). But if the truck was wrecked pretty bad, the engine should be ok and presumably the compression good too.
I'm planning on new water pump, is the Mopar better than reputable aftermarket brands? I see the Mopar is out of stock on Rock Auto but they have Gates.

Exhaust manifolds yes, one is busted from the wreck, I will pull both and check for flatness, replace gaskets. Easy now, hard later.

Compression test is a good idea, but the starter motor in the donor was busted up in the wreck and so was the trans bell housing where the starter mounts, so there is no easy way to do this at least until I have the motor out of my truck. And at that point I'm pretty committed. I'm reassured by the way it hisses and gets hard to turn with a wrench on the crank pulley. Not a scientific test at all but it feels healthy to me.
 

mtofell

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If in any doubt I will replace the radiator.
During my engine swap at the dealer I was told my radiator "fell apart" when they took out the engine. To me this meant they damaged it and had to replace it. The only reason the dealer told me was that it delayed my truck being done by a few days. Factory radiator was back-ordered for weeks but my dealer got an aftermarket (NAPA) approved. I generally agree the radiator replacement should be considered. Definitely a flush but isn't that pretty much natural with the new engine?
 

Jeepwalker

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I guess if you're in MI a new radiator can't hurt. But I've got vehicles much older than yours which get driven in WI salt every winter which are still good: 87 Jeep LOL, 03 Jeep 200k+ mi, some other older vehicles ...and my ram's is still good. So I find it difficult to believe that yours is in rough shape. Of course use distilled water with your new coolant. Yer original radiator could have another 10-12 years in it.
 
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EriikK

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Hey what tool do you use to pull the harmonic dampener off the front of the crank? The book says not to pull on the OD as it will damage the rubber, but the way the spokes are angled a regular puller won't get a grip on them.
The 25264 ones commonly used on GM engines look like they will fit, can anybody confirm? They have three teeth that lock onto the pulley in a twisting motion.
 

Marshall

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I have no idea on the 6.4, but if it was a 5.7, I would look at the cam and lifters while it is out of the truck
 
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EriikK

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Quick update for you all. Put it all back together, drove it a few days, then set out on a two month winter vacation towing the toyhauler. What could possibly go wrong?
Well 7500 miles later the answer is... nothing. Truck ran great. Used no oil, topped up coolant once, used no atf. Computer says I am 6% away from an oil change, that's fine. I could wish for better fuel economy but overall my sweetie and I are completely happy with this truck.
 
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EriikK

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I have a lot of leftover parts from this build but I can't post on the for sale page since I am not chatty enough. :-/

I'll check on that intake manifold, I know I have one but it may have some broken bits on the front, let me take a look.

The biggest lump I need to get rid of is a 6.4 BGE engine, complete with a big tick but it runs and should be rebuildable. I hear some of the high performance folks want that BGE block. What's the best place to sell it and what is it worth? I don't want to leave too much money on the table but getting it gone with low hassle is my goal.
 

Jeepwalker

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What are you seeing for fuel economy (not towing)...if I can ask?

What cab is your truck? Is the "tune" stock? Thanks!
 

Wild one

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I have a lot of leftover parts from this build but I can't post on the for sale page since I am not chatty enough. :-/

I'll check on that intake manifold, I know I have one but it may have some broken bits on the front, let me take a look.

The biggest lump I need to get rid of is a 6.4 BGE engine, complete with a big tick but it runs and should be rebuildable. I hear some of the high performance folks want that BGE block. What's the best place to sell it and what is it worth? I don't want to leave too much money on the table but getting it gone with low hassle is my goal.
Post it on High Performance Rams and Tuned Rams on facebook,it'll sell fast on those pages.
 
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EriikK

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What are you seeing for fuel economy (not towing)...if I can ask?

What cab is your truck? Is the "tune" stock? Thanks!
According to the dash display I can pretty easily get 14mpg on a trip. 15 if it's the kind of roads where I run 60 or so. Around town it's worse, and towing it is single digits. I have not checked to see if the dash display matches what the pump says, I should do that. 6.4L bone stock, stock tune. Crew cab short bed 4x4 2500.
 
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