Got me a new 6.2L Suburban

[Mikey von]

Hey all, I am new here (been lurking for a long while) and we picked up a new burb a few weeks back. I like to type and ramble, so please excuse the length.


Here are the details; 1989 3/4 ton 4x4 190K miles. New 6.2L with around 80K miles. Remanned Th400 tranny with around 30K miles. NP 208 (I think). 4 inch TC EZ ride lift springs in front, blocks in back. It has a stiff 7 leaf spring pack in rear. Rear axle is 14 bolt SF front is 10 bolt (I think) with 4.10 gears. Small 31-inch tires.


Previous owner had receipts for the past 10 years, including engine, tranny, batteries, lift, brakes, ac compressor, oil changes, etc..

 

[Mikey von]

I am looking forward to being able to do work on this truck. It has been about 10 years since I have had a need to work on my trucks, hence I am pretty much a newb under the hood. I had a 66 4x4 when I was 16. I then went to a 75. I was a major rook back then and made some mistakes. This will also be my first diesel.

I am guessing this truck will be driven 80% on road and 20% off road. It will see a lot of highway. We just moved up to the mountains in Northern Cali, so there will be lots of trails and what not. We also get snow. We like to camp a lot. It will be a semi daily driver as we have another car and I walk to work. My wife is at home with our 1 year old and drives to play groups and such. We are planning on having another soon too, so the prospect of my pregnant wife trying to strap a little on in a car seat on a truck with a large lift and tires is not to appealing.


Here is what I plan on doing as money becomes available. I already replaced the alternator (= as it went out.

1) New tires and wheels. I am thinking 33" AT's with black steelies.
2) Drop the lift to 2 inches. I will probably go with TC springs all around as I want to make the ride a little nicer. New shocks, I am thinking good ones.
3) Get shorter gears. I think 3.42 or around there would be good. The thing screams on the highway right now and we travel up and down Cali quite a bit.
4) Get rid of the ugly running boards and replace with some like DPI rock sliders with built in steps.
5) Rear bumper with swing out tire carrier. New front bumper also
6) The last owner replaced the clutch fan with a non-clutch fan. I want to go back to the original set-up.
7) Newer front buckets out of a newer model truck or Suburban. Replace carpet and headliner also.
8) New gauges. I have never liked the extra large fuel gauge. I want a tach and EGT. The trip meter does not work on the OD.
9) I am sure there is more. Let me know any ideas.

I look forward to being a part of this group! Michael

 

[6.2puller]

Remember that the last gear in your drivetrain is effectivelly your tires. By installing larger tires you are effectivelly reducing your gear ratio. I would put the 33s on befor you mess with the gear ratio. I have a 86 with the same gear boxes and it runs 10 times better on the highway now with 35s than it did with 31s when I got it. My burban is a 350 though. My pickup runs a 6.2 with 4.10s and 31s but I have an overdrive auto (700R4) in that one.

 

[tRustyK5]

3.42's and 33's would be a lot better for on the highway...but would make it kinda sluggish around town. I'd look to an overdrive tranny if it sees a lot of highway.

You could probably swap in a 700R-4 for the same money you might spend swapping gears in the diff's.

4.10's and 31's = 3050 rpm @ 65 mph
3.42's and 33's = 2375 rpm @ 65 mph
4.10's and 700R4 and 33's = 1900 rpm @ 65 mph.

Your current combo likely isn't going to net you more than 15 mpg

The plan to swap to 3.42's should get you up to 17.5-18 mpg

Adding a 700R-4 is likely going to put you at 20 or more mpg and still have plenty of grunt around town.

6.2's like deep gears and respond well to them, but having to listen to one scream for mercy on the highway is annoying and costs you fuel mileage. I'm currently rebuilding an NV4500 5 speed for my truck for this exact reason.

Rene

 

[u2slow]

I had the 4.10s in my Suburban with 6.2L/TH400/33s. Still screamed on the highway. I'm at 3.21s now. Great on the highway, but its a slug and hard to use 3rd gear in town. Towing is out of the question. The big'n'nasty TH400 is great for sucking the life out of the 6.2L.

I would have preferred something in the 3.42/3.54 range.... but its hard to turn down a 14bff axle swap that's cheaper than a DIY brake job.

 

[mini_mull]

Welcome aboard. That's a great looking burb. I'm sure you'll love it. I can relate to the loading the babies thing. I load my 4 yr old, and 7 month old in everyday. I've got the metric equivalent of 33" tires, and my suspension is 3/4 stock, which when I compared it to a 1/2 ton was about 3" higher, so I'm sitting almost at your goal height. I think it's perfect for a kid hauler. Your wife will definately appreciate some steps though, especially once number two arrives and one of them goes in the middle. It's impossible for me load a kid in the back middle without a step, but with one it's a breeze. For capable all-terrain tires with excellent road manners, let me suggest the BFG all-terrains. We've loved every set we've had on our kid hauler, DD, weekend warriors. BTW, unless diesels were different than gas, you should have a NP241 w/mechanical speedo in an '89 burb. Also, instead of going 700R4 to get OD, you could go to the 4L80E which came in the '91 3/4ton burbs. It's like a TH-400, but with overdrive. It's more expensive, but much stronger than a stock 700R4. BTW, adorable avatar.

 

[mini_mull]

Too bad your not closer. I'd gladly trade my 3.73 10B&14BSF for a 4.10 10B&14BSF, since I've got OD. Coming to AZ?

 

[MT wheeler]

I ran 33's with 4.10's in my 83 Blazer with the 6.2, 700r4, 208 and it was the perfect comb.

Nice sub--they have alway held a special place with me. Somthing about a big, beefy 4x4 station wagon. Yeah Baby!

 

[linksvu]

not sure where you are today...

I would most certainly stick to going larger tires before anything else, as these guys have said. When you do that, your truck will handle completely different; I have a feeling you will enjoy your current gear ratio then.

I personally would not mess with lossing some of that lift, it does not seem to be worth the effort. Besides, if the PO has that lift on there for some time, the truck is "used to it" and I always try not to change the dynamics of a truck too much...personally.

6.2: Change all fluids (tranny, engine, collant, diffs) right now. Change fuel filter, clean air filter, and put in a good the good filters, not the cheapo ones. If you kill a fuel pump, you will not be happy. A fuel filter is the life of a 6.2

Do a search on the tach...I am in the process of debating whether to a tach conversion my self. Remember, as I have found out, that gauge cluster is overly painstaking to take apart (and not brake anything) so you want to either get used to it or do it once and be done with it.

Great truck, hope you love it. I only wish I could talk the Mrs. into letting me get another Suburban as we have a '99 6.5td.