new 6.2 owner

[stantjeeper85]

Ive aquired a 1985 chevy suburban c10, 6.2 diesel, automatic, 2wd. What I would like to do is pull as much power out of the engine as possible, and convert the truck to a 4wd. I would like to use the truck as a tow rig for my jeep, and be able to move down the highway at 70 - 75 mph, on long road trips, pulling my jeep, with no trouble at all. I want to try rebuilding the current 6.2, and again pull as much hp and torque as i can. I have some ideas, but after stumbling across this site, I thought i would step and ask. If anyone has any useful info, please feel free. Heres a pic of the suburban as it stands now. . . also, it has 230,000 miles on it.

http://memimage.cardomain.net/member_images/10/web/658000-658999/658599_148_full.jpg

[trbankii]

First recommendation would be to buy the 6.2 book here: http://www.thedieselpage.com/62book.htm

That puts a great wealth of information all in one place and into your hands. Invaluable to someone new to the engine. I bought the book for the 6.5 when I bought my truck and still start by picking it up when I am working on the truck.

From there, spend some time reading through and searching the forums. There is a lot of information there and you will readily find the issues that you should look at as well as ways to improve upon what the factory puts out.

Welcome aboard!

[stantjeeper85]

thanks. ill be ordering that book real soon. and Im sure ill have lots of questions. If anyone else would like to throw in some useful tips, feel free!

EDIT:

Actually, I do have a question: Through the researching Ive already done I feel pretty confident I can make good use of the 6.2 as a tow rig. My main focus now is how to convert the 2wd to 4wd. I already know I would need a solid axle for the front, maybe even a bigger axle for the rear, a t-case, and a 4wd compatible tranny. What about a manual tranny? Maybe an NV4500? the truck currently has an automatic. What work would need to be done to the frame? its a 1500 frame. If i throw in beefier front and rear axles, manual tranny and tcase, and beef up the engine, would the frame hold up real well? . . . (sigh) . . . so many questions . . .

[kconnair]

Unless you plan on towing something really, really heavy, I would not worry about the frame, etc. I have never heard of a Suburban frame (not rusted) breaking from towing anything. If you did plan on towing something that heavy, you probably should have a pickup and use a 5th wheel, and a newer truck.

And unless you do, or plan to do a lot of off-road towing or a lot of foul weather (snow) towing, I would leave the truck a 2 wheel drive, or look for a 3/4 ton 4 wheel drive already done. You will have way more time and money converting the truck than if you found one in good shape with what you want already.

Were it me, I would rebuild the 6.2 following Dr. Lee's engine plan, or get a 6.5 turbo drop in with block updates to get more power, update the transmission to a turbo 400, maybe with a gear vendor's overdrive, maybe a posi, and put on a good heavy duty hitch assembly, a good electric brake controller, and leave it at that.

I tow my race car with my '84 3/4 ton 2 wheel drive 6.2 suburban, and it does pretty well. But that is mostly summertime, highway driving. With more power (coming soon), it would be great. Putting a duramax in the old chassis would be incredible, but a tough swap - anyone ever considered it? ;)

[stantjeeper85]

Unless you plan on towing something really, really heavy, I would not worry about the frame, etc. I have never heard of a Suburban frame (not rusted) breaking from towing anything. If you did plan on towing something that heavy, you probably should have a pickup and use a 5th wheel, and a newer truck.

And unless you do, or plan to do a lot of off-road towing or a lot of foul weather (snow) towing, I would leave the truck a 2 wheel drive, or look for a 3/4 ton 4 wheel drive already done. You will have way more time and money converting the truck than if you found one in good shape with what you want already.

Were it me, I would rebuild the 6.2 following Dr. Lee's engine plan, or get a 6.5 turbo drop in with block updates to get more power, update the transmission to a turbo 400, maybe with a gear vendor's overdrive, maybe a posi, and put on a good heavy duty hitch assembly, a good electric brake controller, and leave it at that.

I tow my race car with my '84 3/4 ton 2 wheel drive 6.2 suburban, and it does pretty well. But that is mostly summertime, highway driving. With more power (coming soon), it would be great. Putting a duramax in the old chassis would be incredible, but a tough swap - anyone ever considered it? ;)

Hmmmm. . . this engine plan from Dr. Lee you speak of would be the plan in the 6.2 book correct?

The suburban will be the tow rig for my 3200 lb jeep. It certainly will never be hauling anymore than 10,000 lb max (including trailer weight). So that said I suppose the frame will be fine. I want 4wd for the truck simply because i do. Ive always driven 4wd vehicles because they just make more sense TO ME, because ill never know when i may end up needing it, and i have been in this suburban before and needed 4wd. The truck has been in my family since it was bought new, so it has some sentimental value. that being said, i dont want to sell it and i dont want to frankenstein it with another truck. I know Ill be swapping out some major driveline components in this project, but my goal is to keep the original 6.2, the original frame, and the original body, and end up with a 4wd, manual tranny, 6.2l 1500. I know it will cost a pretty penny, and i have no problem with that. I also understand it will be time consuming and difficult, but thats why its fun! ;) :cool:

[86M1008]

im no gearhead but i seen 2wd converted to 4wd on tv they used a plasma cutter and torched the whole front of the frame right off and welded in one from another truck.

[Supertrucker]

It is very possible to convert your rig to 4wd. It's obviously not easy as you would need to cut off the front suspension bracketry and weld on the spring hangers from a 4wd. There are alot of measurements involved with getting the hangers to line up, the axle to center, and to make sure the rig will track straight. Nice thing about early Chevy's is the frames are the same for the most part and you can go searching in your local junkyards for all the parts you need. Also, you really wouldn't need to swap transmissions as your current Th350 would live just fine with some upgrades. For the transfer case to adapt you need the output shaft and tailhousing from a 4wd tranny. The stronger setup would be to borrow the entire drivetrain from a 3/4 ton as you would get a Dana 44 front end (or a corporate 12 bolt), a beefier Th350 or the more desireable Th400 3 spd auto, Np208 transfer case, and the corporate 14 bolt rear end. Also you can take the leaf springs, hangers, sway bar, and the heavier duty brakes. So I'm not an expert but I hope this helps.

[DmaxMaverick]

Welcome to the Forums, Supertrucker.

The tranny, of stock, should be a 700R4. It will do well if built with updated hard parts and a shift kit. TH350's don't survive behind these Diesel engines. The TH400 was used for 3/4 and 1 tons.

[Supertrucker]

Thanks Dmax and of course my mistake. I wasn't thinking when I mentioned the Th350, thanks for the correction. I know some Th350's found homes in 3/4 tons however most were 400's. With a quality rebuild and a good shift kit I would assume that a 700r would live happily behind the 6.2. I might have the opportunity to buy an '89 Sub with a 6.2 that includes a Banks turbo kit. Low miles for it's age, 4wd, power everything, and not a scratch, ding, dent , or spot of rust anywhere.

[DmaxMaverick]

I've never seen an OEM 350 behind a 6.2, but I've seen the results of attempts. Ugly. A 700R4 will handle all a 6.2 will put out if built right. My '85 is testement to that. A $300 upgrade back in '88 and it has survived for ~450.

[Yukon6.2]

Hi Supertrucker
Nice Superliner in your av,wish mine still looked that good.You are right about the sound of the Mack Diesels.Nothing beets the power of the Mack either.

[Supertrucker]

Thanks Yukon. Yeah I only wish that were my Superdog. Don't have one yet but hopefully someday in the future. My upcoming purchase is an '89 Sub with a Banks 6.2. This is one I cannot pass up.

[doncannon]

Hello all,

stantjeeper85: you would need to know the gear ratio of the rear end. To find out a quick was is to jack up the sub right underneath the rear pumpkin (i know this has happened to me so please make sure it is on the level and both sides of the front tire are blocked so it dont roll...we dont want to loose you). If you rotate one tire and the other one moves just count the complete rotation of the drive shaft (posi) if both tires DO NOT move then you will need to rotate said tire twice and count the driveshaft rotations. I am guessing it should be between 3.08 to 3.73 this is your gear ratio. You will need to find a front rear with the same ratio. That would be the quickest way.

Now if it were mine I would buy a rusted out sub like we have in NE of the US and then you would have everything you would need. Maybe one with low mileage and a 3/4 ton. You could find one with axle ratios and maybe another 6.2 and th400 and transfercase like you want and all parts necessary for the swap...saves you looking for pieces. The BONUS would be that you would have another sub to get all measurements from measure twice and rip apart once. You could just swap out frame and driveline.

I hope I did not confuse you,
Hope this helps,
Don

[84 Convert]

My K2500 was a 2wd to begin with, and I did alot of looking at the frame on it before the swap. It seemed to me that MOST not all of the bracket holes were already in the 2wd frame for the 4wd stuff. I ended up getting a whole frame and swapping the body over I had no attatchment to the frame so this was a viable option for me. I had less than $1000 into the 4wd components so it can be done for less money than most suspect if you are a real scrounger. One thing that made this swap easy was using a friend's shop that has an overhead trolley crane.

Good luck and happy swapping!!

Gregg

[stantjeeper85]

After alot of thinking Im starting to realize it may be best to just swap the body ovet to a 4wd frame. So here's my question: does the 4wd frame HAVE to come from another suburban? or can it come from ANY GM K30 from that year range (80s)?

[84 Convert]

The body mounts will be different between p/u and 'burb. I suspect that and the dfferent rear frame width on the 1-ton will be the sticking points.

Gregg

[stantjeeper85]

What axles come under the K30 80's suburban? If i wanted to replace the front and rear axles, what would be good replacements? d44 front? d60 front? d60 rear? d80 rear?

Also, I really prefer to swap out to a manual tranny. I just about also prefer to buy a new aftermarket one. I dont trust rebuilt trannys too much. that said, what would be a good tough manual tranny to consider for the 6.2?