Hey DieselDan,4L80E/35"tire question

[C.K. Piquup]

I also own a`91V2500Sub w/4L80E and have 35"tires to install.My question is,what did you do to correct the VSS?I`ve been pondering this and have not found a satisfactory solution,yet.Did you just change the gearing to 4.56s?I figure that should do it for countering the increased diameter.I was hoping to avoid that,though,until later when I have enough "$" for a locker&tru-trac.Do you know an adjustable VSSB at the trans end of the harness?

[Diesel Dan]

CK,

Tell ya what, since my speedo is already calibrated I'll just trade ya trucks. Too save you work and all :D .

I have 4.56 gears in the truck. Also picked up a VSSB with the 14 pin jumper inside. I followed the article in the '99/98 DP article on the VSSB calibration.

I have considered installing a Cummins into this truck and then regear with 3.73s. Well see, maybe someday.

[C.K. Piquup]

Who makes the VSSB you are using?I`ve tryed Jet Performance,Superlift,and Tuff Country(it`s their lift/SoftRide springs).Thanks for gettin` back.Yeah,I`ve also pondered the 6BT in a Chevy.A Suburban would be wild.

[Diesel Dan]

The 14 pin units are usually service units.
I called Gear Vendors once and they said about $100 for VSSB.
The 1999 feature articles has a right up on it. I don't think GM stocks them anymore. I don't recall how I came across the one in the truck. I did stop at a trans shop and he had a drawer full of old VSSBs that he replaced after regearing trucks and just ordered the proper unit. I found one 14 pin one and he sold it to me for $20 or something. We tried installing a 12 pin and 2 pin micro-switch so I could tune as I please. But the circuit board couldn't handle the heat and we damaged the cruise circuit.

[C.K. Piquup]

Thanks again.I`ll have to dig out my articles and get to work.The springs(Tuff Country/EZride),shocks(6 RanchoRS9000)/dual strg stabilizers,tires/wheels(WranglerMT/black steel RockCrawlers),and Warn premium l/os are loaded in the back and ready to go to the shop.My brother-in-law has bumper lift & nice heated shop.I`d like to think my "cave man" days are over.

[Diesel Dan]

Man, I would have liked to run across your stock sub when I was looking. Didn't run across any '91 diesels at the time I was looking. Mine came out of CA and is rust free, ALL BLACK :cool: .

[C.K. Piquup]

I,too,was looking at some CA Subs(in Indiana)when I found mine in a DC area book about 100mi.away.It was owned by the WashingtonSuburbanSanitaryCommission,a plus on servicing and minus on cosmetics(faded/peeling tops and many little dings.It is rust-free(Zeibarted)and bone stock.It`s a base-line model with few options,including:6.2,posi,a/c,am/fm,and all heavy-duty stuff.The last of the"True Truck"Suvs.I almost hate calling it that.It had 96,000mi.It filled the bill perfectly,a jump in and get away rig.Now,about that Unimog.....

[Diesel Dan]

Originally posted by C.K. Piquup:
Now,about that Unimog..... Yeah, kinda wish I had bought the other two he had. One a runner and the other for parts.

My sub had around 95K on it when I bought it. Had to go 600+ miles to PA to get it. Lift was done when new, gears by previous owner. He just moved back to PA from CA. It's a loaded conversion, 4 leather captians chairs, TV, CD w/remote changer, etc.

[C.K. Piquup]

I read the article,I`m just not sure it applies to my vehicle.It even states some vehicles don`t have reconfigurable modules.My Chevy parts man showed all listings of sensors/modules for this vehicle with none for VSSB(or anything that sounded like it would be for this function).The article doesn`t cover"tapping"one in.Is this what you did?I just figured my ratio,4.10.I was assuming it might have been a 3.73.

[C.K. Piquup]

I figured it out.I got out all the formulas and figures and decided not to touch any thing electronic,KeepItSimpleS(what`s the other S for??).By using the dia.of the original 235/85s and gearing(4.10),compaired to the dia.of the new 315/75s and 4.56 gearing,the numbers come out close(very)to identicle.That`s #s like divide ratio,MPH@RPM,and new ratio.If I didn`t change gearing,the 35s would give a 3.73 ratio.Then I could swap for 3.73 module.But I want to keep the grunt and put my$into traction aiding devices.

[britannic]

Originally posted by C.K. Piquup:
I figured it out.I got out all the formulas and figures and decided not to touch any thing electronic,KeepItSimpleS(what`s the other S for??).By using the dia.of the original 235/85s and gearing(4.10),compaired to the dia.of the new 315/75s and 4.56 gearing,the numbers come out close(very)to identicle.That`s #s like divide ratio,MPH@RPM,and new ratio.If I didn`t change gearing,the 35s would give a 3.73 ratio.Then I could swap for 3.73 module.But I want to keep the grunt and put my$into traction aiding devices. Did you use 4" or 6" lift to fit those 35" tires to your rig?

[C.K. Piquup]

I used a 4" lift.They clear,I wanted to keep the lift to a minimum.

[britannic]

Originally posted by C.K. Piquup:
I used a 4" lift.They clear,I wanted to keep the lift to a minimum. Did you leave the pinion angles as they were, or did they need shimming? I'm planning the same lift using rebuilt springs so I don't need to use blocks.

[Dieselboy]

The pinion angle should work well, but consider upgrading to a 1350 Saginaw CV in leiu of the GM 3R CV which maxes out pretty quickly.

If you're thinking about 35s, keep the sawzall handy. Minor trimming clears well enough for street and mild off-roading. Any real flex will result in the tires and fenders getting a little too cozy. I ran a 4" lift, upgraded to 5", and finally settled on 6" as my maximum. The best combination seems to come from a 4" suspension, 1" body or 1" zero rate add-a-leaf, and 1/2" longer shackles with the fenders trimmed back about 3-4" at the bottom. This keeps the center of gravity pretty low, but clears the tires just fine for off-road use. I'll snap some photos this weekend of my trimming.

LWB pickups are especially easy to setup since they're so darned light in the rear. They can use a decent amount of lift without fear of moving the COG too high.

[C.K. Piquup]

David`s right,pinion engle will be fine w/4".Also 6"lift clears body for all uses the truck can handle.I ran 35"/4"lift on my`84K30PU work truck w/no trimming and no clearance problems.The lift was the HD type and excess wheel travel was not my goal.I carried alot of weight up on the racks regularly,too.Most of my off-road use was access to building sites and then around the site.I did some playing,too.But no"rock-crawling".If the Sub rubs,it`ll get a trimmin`.I have EZride springs for it.I don`t expect any extreme use with this one,either.

[Diesel Dan]

Originally posted by C.K. Piquup:
I ran 35"/4"lift on my`84K30PU work truck w/no trimming and no clearance problems.The lift was the HD type and excess wheel travel was not my goal. Wow, you are lucky.
I have 6" HD springs with 35s and they are very close to the rear of the front fenders while turning. I am running 16.5x9.75 weld wheels and 35x12.5R tires. When I was running my 15x35-16.5 super swampers they hit when into and out of some driveways. Those tires measured an actual 33" tall.

I had an issue with front CV clearance. When in 4wd the front CV would hit the trans cross member. Currently I have 3/8" shim under the t-case mount and between the frame/cross member. This way my drivetrain is at proper angle, until I get around to pulling the crossmember off. Then I will cut/notch the crossmember and reweld for proper fix.

I don't hardcore wheel the truck. It is manly a road cruiser and sees the sand dunes couple times a year.

[C.K. Piquup]

On that`84 I was running BFG All/Terrians.They are a small 12.50/35 minus side lugs.It had 9.75x16.5 OEM-type(hub cap)rims.I always wondered if they had less offset than"custom"rims.Alot of guys run 8"rims,that usually helps with body clearance.Mine aren`t mounted on the Sub,yet.I may have to do some cutting with these rims(10").I`m waiting for new 4.56 gear-sets(w/locker&tru-trac).

[Dieselboy]

Though long overdue, I have my latest fender trimming pics.

The 35s had a way of self-clearancing fenders on the older body style, and since they have had a tendency to rub on full stuff, I figured it was past time to trim.

The driver side was crumpled from this last trip to Mason.
http://www.oliverdiesel.com/images/fendertrimming/crumpledfender.jpg

Marking the cut.
http://www.oliverdiesel.com/images/fendertrimming/markingcut.jpg

The inner fender was persuaded to match.
http://www.oliverdiesel.com/images/fendertrimming/innerfenderpersuaded.jpg

This should be the last time I have to cut.
http://www.oliverdiesel.com/images/fendertrimming/clearance.jpg

One more.
http://www.oliverdiesel.com/images/fendertrimming/clearance1.jpg

I realize that this is more than most folks are willing to hack into what may be virgin sheet metal, and that's entirely understandable. I was having small heart attacks the whole time I was cutting. This much metal cutting makes enough room for my current 35s and future 37s, so keep that in mind. Repair panels are readily available, so this process is reversible when and if the time comes.

:cool: