6.5 turbo diesel

[mattpiotr]

well today i discovered that my rings are starting to go bad on my 86 2500 350v8....well i am kind of a diesel freak and i have 1992 gmc 2500 that was T-Boned between the cab and bed with a 6.5 Turbo diesel on 31,579 original miles. i was wondering how hard it would be to pull that 350 out and drop that 6.5 turbo in my 86? what are the steps to doing it? is it a expensive process? should i take my turbo 400 transmission out and replace it with something else or just rebuild it up? and has anybody else done this to a similar range year truck? every detail would be accepted and appreciated Thanks Fellas.

[AntiGov]

I dont have the details on that .....but man that sure seems like a great idea!!

[Pyrotechnic]

It's not a tough swap since the 6.2/6.5 share the same bellhousing and use the same motor mounts as a small or big block chevy v8. It's a bolt in deal. You can use the transmission that came behind the 6.5 or the turbo 400. If the 6.5 had a NV4500 or 4L80E behind it, then either is the preferable trans because of the overdrive.

Other than that, there is wiring. The 6.5 of that year should be mechanical injection which keeps the wiring simple. If it had a 4L80E there will be a computer for that and some wiring to move over if you want to use that trans.

Also the fuel system. It's a good time to drop the tank and clean it out, and you might need to make some plumbing changes for the 6.5.

I might be missing some things, but it's not a complicated or expensive swap by any means.

[mattpiotr]

Originally Posted by Pyrotechnic

It's not a tough swap since the 6.2/6.5 share the same bellhousing and use the same motor mounts as a small or big block chevy v8. It's a bolt in deal. You can use the transmission that came behind the 6.5 or the turbo 400. If the 6.5 had a NV4500 or 4L80E behind it, then either is the preferable trans because of the overdrive.

Other than that, there is wiring. The 6.5 of that year should be mechanical injection which keeps the wiring simple. If it had a 4L80E there will be a computer for that and some wiring to move over if you want to use that trans.

Also the fuel system. It's a good time to drop the tank and clean it out, and you might need to make some plumbing changes for the 6.5.

I might be missing some things, but it's not a complicated or expensive swap by any means.

yes the transmission is the 4500. and it does have the mechanical injection. now would a 400 turbo be better or a well build 700r4 for the over drive?personally i love the turbo 400.

[GmtGmt]

you would have to get a diesel convert for the th400
but i would keep the 4500 if it was me.

pretty easy swap...

[joe231]

Do it!!

I think you will need to do a custom down pipe.
you may have to run it outside the frame and trim the inner fender.
Please take in process pics!!

I have a 84 K20 Burb with a 6.2L/700R4 combo, it does great and gets excellent mileage.
I also have a 91 V3500 with a 6.2L/4L80E combo, I'm planning on putting a turbo set up from a 6.5.
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[Pyrotechnic]

The NV4500 you have is the best transmission to use. It's very strong, it has overdrive, and there's no electronics. You will have to cut the floor and add a clutch pedal. Dodge also used this transmission in their Cummins powered trucks and lives behind those motors just fine.

The best automatic to use is the 4L80E. It is strong and can take the power in stock form, and it also had overdrive. The 4L80E that came behind a 6.5 turbo of that year will have a standalone computer with the correct shift points for a diesel. You need the computer and all of the associated wiring.

The Turbo 400 will take the power, but depending on what gears you have, your highway speed maybe a little limited and your fuel mileage will suffer because of it. It really helps to have the extra gear that the 4L80E has. If you want to use the Turbo 400, you will have to install a governor that is correct for a diesel, and you will need a torque converter for a diesel as well.

The 700R4 is a poor choice for this swap. It is too weak in stock form and will be really expensive to make strong. There's a good reason GM never put one in a 3/4 or 1 ton truck.

[joe231]

Originally Posted by Pyrotechnic

The NV4500 you have is the best transmission to use. It's very strong, it has overdrive, and there's no electronics. You will have to cut the floor and add a clutch pedal. Dodge also used this transmission in their Cummins powered trucks and lives behind those motors just fine.

The best automatic to use is the 4L80E. It is strong and can take the power in stock form, and it also had overdrive. The 4L80E that came behind a 6.5 turbo of that year will have a standalone computer with the correct shift points for a diesel. You need the computer and all of the associated wiring.

The Turbo 400 will take the power, but depending on what gears you have, your highway speed maybe a little limited and your fuel mileage will suffer because of it. It really helps to have the extra gear that the 4L80E has. If you want to use the Turbo 400, you will have to install a governor that is correct for a diesel, and you will need a torque converter for a diesel as well.

The 700R4 is a poor choice for this swap. It is too weak in stock form and will be really expensive to make strong. There's a good reason GM never put one in a 3/4 or 1 ton truck.

My 84 3/4 ton Burb came from the factory with a 700r4
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[madcow75]

I am doing the convesion myself and I was just looking at the turbo downpipe and I think it is going to be easist to run it outside the frame because of the transfercase and front driveshaft. I guess its a good think I got rid of my saddle tanks otherwise the would be in the way.

[odee]

I've swapped a few 6.5t into these body style trucks. I have had good luck using a 7.3 ford down pipe cut up some. We have also swapped some into the 67-72 trucks also.

[joe231]

Sweet!!
Got pics?
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[Mattman2010]

From what I understand you will have to do something with your A/C box if you have A/C. I have a 6.2 in my K30 Crew Cab and have a 6.5 turbo setup to put on it but the A/C box is what is keeping me from doing it right now. I am not running A/C right now so I might just cut that out of the box for now.

[Rollinsqrbdy]

Well i dont know much bout diesels but im fixin to pick up a 83 swb gmc with a 6,2 diesel thats fixin to get jerked out as soon as i get it!!!! Sorry dont mean to jack ur thread

[special-K]

In a square body the heater box,at least the a/c ones,interfere with the turbo/downpipe.

Originally Posted by joe231

My 84 3/4 ton Burb came from the factory with a 700r4
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The first year overdrive was offered in 3/4 ton and heavier trucks was 1991 and those were 4L80Es. The 700r4 was never used in any 8-lug truck or Suburban.

Originally Posted by Rollinsqrbdy

Well i dont know much bout diesels but im fixin to pick up a 83 swb gmc with a 6,2 diesel thats fixin to get jerked out as soon as i get it!!!! Sorry dont mean to jack ur thread

Is something wrong with the 6.2 or are you just fixin to buy a lot more fuel? I'm still wondering what the point of your post was.

[joe231]

Originally Posted by special-K

The first year overdrive was offered in 3/4 ton and heavier trucks was 1991 and those were 4L80Es. The 700r4 was never used in any 8-lug truck or Suburban.

Mind sharing where you got that info?
This isn't the first 8 lug Burb I've seen with a 700R4.
I don't think it's been swapped in, but now I'll have to do some investigating...
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[special-K]

It's a common known fact. GM used the TH400 in 3/4t and 1t until the 4L80E came out in '91. I own a '91 V2500 Suburban diesel and from owning it 10 years,buying parts for it,and conversations about Suburbans I know it's the first year for O/D in V2500 and V3500s,as well as the R2500/3500s. I also owned a '90 Blazer I bought new that came with a 4spd manual,while 5spds were available in the new body style trucks. The same is truck for all Suburbans through '91. They never came with a New Venture o/d transmission. Can you verify that yours is original or listed on the SPID? I am always willing to learn and/or be proven wrong. I sure don't know everything.

[joe231]

The SPID is MIA. Lol

This is an old fleet Burb from an oil company up here. It is entirely possible that someone swapped it in, but all the parts stores list the 700R4 as a trans that was available in this rig. 84 K20 suburban with a 6.2l diesel.
I'm gonna ask the resident expert if he has any input...
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[Keith Seymore]

Both the Powertrain Chart and the program plan book for an '84 K25 Suburban show a three speed auto as standard/base, and an overdrive auto available as an option.

Unfortunately, this document does not specify if the overdrive is a 700R4.

[joe231]

Cool!
Thanks Keith!
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[special-K]

Well,I learned something there. I own a '91 3/4t 4wd Burb and have had many a conversation about that being the first overdrive in a 3/4t. I realize it's the first 4L80E,but that's not where the confusion was. I also had an '84 K/30 diesel with every option under the sun the previous owner ordered. It had the TH400 and the P.O. added a Gear Vendor overdrive. I guess he just wanted more strength. I guess by '84 he already felt the 700r4 wasn't tough enough for him. I have never seen a 700r4 in an 8-lugger,but I checked over on CK5 and there was a thread with a few examples,as well as Keith's document.

On another note..I see it says the 4spd manual wasn't available on C and K 20s with 454 or diesel? I have seen quite a few exceptions to that.