Greetings this is my first post. I just read most of the 6.2L forum for the first time.

I recently purchased a 1984 GMC Rally Wagon van w/ 6.2L v8 to haul the band gear around with. 1 owner, build in Canada, (1)52k miles. It has several issues I'm hoping ya'll can lend advice on:

Rear axle tubes are bent up slightly, differential grinds when applying much torque. Currently calling around trying to find a replacement rear end. A big question is what gear ratio to get. This van does have a hitch, but I really have no plans to tow a trailer, probably carry a max of 500lbs of gear and 4 people. I would like to get the best possible highway mileage, also ;)

Two numbers located on the back of the diff...

1405525 and F44 - Does either of those tell me the ratio?
10 lug backplate, backplate -> yoak, 15"
5 lug wheel, 23" axle (diff -> wheel)

It think I'm looking for a 3.42, but any other recommendations would be great.

--
Biodiesel conversion. Replace hoses & seals w/ new materials.
Where can I find a list of the hoses & seals that need replacement?

Thanks
Zetan

Another question,

How do I go about adding a tachometer to this engine?
Any recommendations on brand or supplier?

Thanks
Zetan

I have a 3.08 in my Blazer and I get around 17 mpg. The Van is probadly lighter too. You go a little slow on hills, but you have alot of power. ]

They make various diesel Tac's too, just look around JC whitney.

sounds like you have a few options.

if you are interested in your current gear ratio look for it on the RPO code list. not familar with vans but seen them on the underside of the hood on some. should say something like "standard axle 3.42 gear rat" sometimes its not mentioned.

if you cant find the list, do the test. jack up the rear so one wheel is off the ground, but the other will not move. mark tire and driveshaft. in netural turn the tire 2 revolutions and count the time the driveshaft turns in that amount of time.
3 =3.08:1
3 1/3=3.42:1
3 3/4=3.73:1
4 1/8=4.10:1

if you have any in the area, you could go to a junkyard. i know if I go to mine tomorrow, theres like 5 c-10, 3 c-20, and 1 c-30 vans, all with axles. regardless of gear ratio im guessing most should fit from the 10 and 20 series vans. with luck you could pull a good one, and would be cheeper is my guess. just an idea.

theres about 3 different tachs out there. Im using the autometer #2888. 0-5,000 rpms, black with white letters, 2 1/8 diameter. real easy hookup. sensor wireclamps onto the alternator, run the wires, thats it. local 4x4 shop, napa or any dealer that supplies guages would be able to order one. theres a thread about this somewhere around here...

yep.
http://dieselplace.com/forum/showthread.php?t=37649