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I have a 1996 chevy 2500 with a 4L80E trans that has a blown 6.5. I have the opportunity to buy a 1995 3500 dump truck with a standard shift that has a lower mile 6.5L. I can't find anywhere on the internet to tell me if these two engines are the same. I seen forums that say the 94&95 are the same in their own right, but doesn't really explain as to why. All the components on the front of my 96 and the possible donor 95, ie; alternator etc, all all located differently on each engine. I do not know if the engines are the same where the bolt holes are such as same locations and thread sizes to be able to take all the front components off the 96 and swap them to the 95?? Are the tranny bolt patterns the same from the 95 standard to the 96 automatic 4L80E to bolt the 4L80E to the 95? Despite the front parts, are these two engines the same? Are the oil cooler line ports the same thread size, in the same locations? Is there anything different as far as oil pressure switch, sensors, what makes the fuel pump on the frame operate, anything at all that would make this either not a good swap, or I would need to know to make the 95 work in the 96 truck properly? Or will it not work all together and I should not buy the 95 truck at all. The 95 truck will not start because the prior owner got wire chopping happy to where there is no juice to the glow plugs, he cut in a cheapo ignition switch hanging from the column. I tried putting power to all the wires that went to the original switch, but could not get anything else, like glow plugs, to work. I heard it turn over, sounds like it wanted to maybe kick with starter fluid, but didn't! I even hot wired the pump on the frame, prior owner claimed that the pmd was new and it has been relocated, but still nothing,, but it turned easily, did not have any noises and only supposedly has 80k miles on it (says the speedometer)! So, with that said, and the engine actually looks clean yet, I am hoping wired properly it would start. But if these are 2 totally different engines due to year or transmission bolt pattern, etc.., I do not want to waste the money buying the 95 and taking that chance. I am really hoping to find maybe someone who worked a GM dealership in the 90's who really knows their stuff and these 6.5's inside and out!! If you are out there,, and can help me with these questions,,, oh thank you!! Thanks to you all for reading my dilemma and I hope the Guru I seek is among you!:)
 

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Welcome.
The engines are the same except for the accessories.
The oil pressure switch location may be different but no problem to adjust.
I would do a compression test on the donor before installing.
What is wrong with the 96 engine?
 

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I have a 1996 chevy 2500 with a 4L80E trans that has a blown 6.5. I have the opportunity to buy a 1995 3500 dump truck with a standard shift that has a lower mile 6.5L. I can't find anywhere on the internet to tell me if these two engines are the same. I seen forums that say the 94&95 are the same in their own right, but doesn't really explain as to why. All the components on the front of my 96 and the possible donor 95, ie; alternator etc, all all located differently on each engine. I do not know if the engines are the same where the bolt holes are such as same locations and thread sizes to be able to take all the front components off the 96 and swap them to the 95?? Are the tranny bolt patterns the same from the 95 standard to the 96 automatic 4L80E to bolt the 4L80E to the 95? Despite the front parts, are these two engines the same? Are the oil cooler line ports the same thread size, in the same locations? Is there anything different as far as oil pressure switch, sensors, what makes the fuel pump on the frame operate, anything at all that would make this either not a good swap, or I would need to know to make the 95 work in the 96 truck properly? Or will it not work all together and I should not buy the 95 truck at all. The 95 truck will not start because the prior owner got wire chopping happy to where there is no juice to the glow plugs, he cut in a cheapo ignition switch hanging from the column. I tried putting power to all the wires that went to the original switch, but could not get anything else, like glow plugs, to work. I heard it turn over, sounds like it wanted to maybe kick with starter fluid, but didn't! I even hot wired the pump on the frame, prior owner claimed that the pmd was new and it has been relocated, but still nothing,, but it turned easily, did not have any noises and only supposedly has 80k miles on it (says the speedometer)! So, with that said, and the engine actually looks clean yet, I am hoping wired properly it would start. But if these are 2 totally different engines due to year or transmission bolt pattern, etc.., I do not want to waste the money buying the 95 and taking that chance. I am really hoping to find maybe someone who worked a GM dealership in the 90's who really knows their stuff and these 6.5's inside and out!! If you are out there,, and can help me with these questions,,, oh thank you!! Thanks to you all for reading my dilemma and I hope the Guru I seek is among you!:)
Welcome to DieselPlace

The engines themselves are the same. The exceptions are the 95' is OBDI and the 96' is OBDII.
When the OBDII transition happened GM changed the location of the Alternator over to the Passenger side and the AC to the Driver's side and installed an advanced ECM for the electronics to be monitored

The OBDI systems used the OPS(Oil Pressure Switch) to deliver power to the lift pump causing lots of stress on the OPS causing premature failure of the lift pump and OPS.
GM corrected this in the 96'+ models and added a relay to take the load off of the OPS.
The OPS location also changed slightly from 95' to 96'
the 95' model year OPS are easy to access and the 96' model is a pain in the butt to get at because they moved it under the #7 intake finger and angled it making it very hard to service.
The Oil Cooler line sizes changed in 1997 to 1/2" ports

the 95/96' years should have the 3/8" ports

IIRC, the differences for the trans will be determined by 2 or 4wd vehicles
 

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Discussion Starter #4
Thank you OKDually! They are both 4wd, just one auto and the 95 standard. So, to be sure of what you are saying when you say the engines are the same,, all bolt holes in the front are the same , so I can just swap all the 96 alternator and a/c and all right over to the 95 engine with no issues?? And all the OBDII stuff that may be needed for the 96 will also transition into the 95 in the same locations, except of course the oil pressure switch.? And Glagulator,, I will do a compression test! Thank you for that! Sometimes the simplest of things to do are overlooked until someone else says it,, then I smack myself in the head and think, Duh,, I shoulda thought of that! :)
 

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One consideration that you need to make is to replace the oil cooler lines with a better one such as the one from Leroy.

The quick connect that attached to the block often failed ruining the engine.

The new threaded connection is very easy to install on the engine block when engine is out.
 

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Thank you OKDually! They are both 4wd, just one auto and the 95 standard. So, to be sure of what you are saying when you say the engines are the same,, all bolt holes in the front are the same , so I can just swap all the 96 alternator and a/c and all right over to the 95 engine with no issues?? And all the OBDII stuff that may be needed for the 96 will also transition into the 95 in the same locations, except of course the oil pressure switch.? And Glagulator,, I will do a compression test! Thank you for that! Sometimes the simplest of things to do are overlooked until someone else says it,, then I smack myself in the head and think, Duh,, I shoulda thought of that! :)
Transfer just the 96' engine over and install all the 95' accessories onto it.

The only problem you will have is the Manual trans install.
You will need to find a 95' ECM with manual trans programmed EPROM or have the ECM reprogrammed to the manual trans.

Or you could install the 96' engine, trans, complete engine harness, and ECM over.
You will also need to replace your IGN switch over for the manual trans option.
 

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Discussion Starter #8
Oh no,, I am only taking the engine out of the 95 to swap into the 96 ,, not the standard tranny from the 95! I am keeping the 4L80E and everything the 96 came with,, I just was hoping to take just the engine out of the 95, strip everything off of it and install all the 96 components on it and putting it in the 96 ! Thats it! I just needed to know if I could do that? if the auto tranny in the 96 would bolt up to the 95 engine, as i am keeping the tranny and everything that came in the 96 just as it came! Just an engine swap!
 

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Oh no,, I am only taking the engine out of the 95 to swap into the 96 ,, not the standard tranny from the 95! I am keeping the 4L80E and everything the 96 came with,, I just was hoping to take just the engine out of the 95, strip everything off of it and install all the 96 components on it and putting it in the 96 ! Thats it! I just needed to know if I could do that? if the auto tranny in the 96 would bolt up to the 95 engine, as i am keeping the tranny and everything that came in the 96 just as it came! Just an engine swap!
Sorry about that..

You should be able to transfer everything over.
The only thing I am not sure of is the Engine harness fitment with the change over on accessories for 96'

Worse case scenario is that you just reuse the 95' accessories onto the donor motor.
IIRC, The trans should mount up.
You'll have a better visual when you get there on disassembly of the donor and the blown motor.
 

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" I heard it turn over, sounds like it wanted to maybe kick with starter fluid, but didn't!"

It is highly recommended to NOT use starting fluid with these engines. You can do a lot of damage very quickly. Glagulator or OKDually could probably tell you exactly what can happen if you do.
 

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grtpumpkn just needs the 95 long block, no need for any other changes, just swap it over.
 

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Discussion Starter #12
Dhoa!!!,, that is what I was hoping someone on here woulda also known, if the trans bolt up was the same for both standard or auto trans between both years, cause I didn't want to waste the money on the 95 donor truck and take them both apart just to find I wasted all that time and money and be left with 2 apart trucks, ya know? And if everything from the 96 (which is the truck I would be putting the donor 95 engine in) bolts onto the donor engine the same,, then the 96 harness should fit on all the 96 components! All I am looking to do is taking the engine out of the 95 stripping it down to just the long block, putting all the 96 components on it, and sticking it in the 96! Each reply I am getting starts off where I feel good what I am reading, then getting confused as I read on as it seems i might not be explaining what I am looking to do well enough?!
 

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Discussion Starter #13
Thanks LinePilot! yeah I know about starting fluid,, I hot wired the lift pump to be constant, cracked the front injector line till I saw fuel coming out,, then just shot a bit just to hear that initial, possibility, kinda sorta, like it mighta fired if it were set up to run well! Someone did one heck of a wire butcher job on this truck!,, y? I have no idea,, but before I put any effort or even money into purchasing this truck for it's engine 1, I wanted to be sure it wasn't another blown boat anchor and it sounded as if it would at least turn over without any knocking, and if it would possibly pop just a bit giving me the hope it would fire if everything wasn't butchered! Annnd 2, that I would find someone well versed in these engines enough to know if the 95 long block only, would be able to replace the 96 where everything from the 96, tranny, alternator, sensors etc,, all would fit on the 95 long block and it would bolt right in,,, before I spent the money on the donor truck and ripped them both apart! Cause if the possibility that it might not work for the application I am looking to use it for,, then I wouldn't buy the 95 truck and just have the 96 truck sit until I pulled the engine and just sent it out to be rebuilt?! Which it would sit because I already have a 149k 6.5 1999 diesel engine sitting at the machine shop for the past few years already waiting to get finished,, for another sweet truck I have where the 6.5 tanked!!!! yup! I see I am big on the run on sentences! :)
 

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If you did not personally (in person) see and hear this engine running, which I believe you didn't, you better be paying scrap price for that boat anchor you're about to gamble on. Sellers nowadays are more prone to lying than they are breathing. Buyer beware. If you're getting that boat anchor for free, it might not even be worth it depending on what happens. If all of the gambling pays off...........I will be shocked and stunned, and I will celebrate your victory with you. That is, if you come back and share your success story.
 

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Discussion Starter #15
Thanks TankYanker! Yeah,, I know these engines are usually good weight for a truck load of scrap metal! Evvveryone I know gives me a good kick in the *** for buying another 6.5 truck, especially when I already have one that I had nothing but issue after issue with until it blew up at only 149k. But I will come back and let you all know how things went!! It may be a while because I am financially handicapped,, but I will be back on to let you know yay or nay either way!!
 

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" I heard it turn over, sounds like it wanted to maybe kick with starter fluid, but didn't!"

It is highly recommended to NOT use starting fluid with these engines. You can do a lot of damage very quickly. Glagulator or OKDually could probably tell you exactly what can happen if you do.
You can blow out the precombustion chambers (pre cups) right into the block. So hard in fact itll leave divers or impressions into the deck. Head damage. Irreparable damage... most of the time.
 
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