I think it's finally re-gear time. Where to source parts?

[Herbie]

So after like seven years (five with a lift and taller tires), I'm finally at the point where I can make the spend on doing a re-gear and adding a locker in the rear on my van.

I've got local Rx for a couple of shops that can do the setup, but since the Astro is an oddball, I really want to go in with parts in-hand (or at least picked out) and just have them do the labor, rather than have them get into sourcing parts for me. (Had a bad experience with one local gear shop trying to "talk me out of" spending any money on the stock axle setup - making the hard upsell for custom D44s at both ends. LOL)

So with that - where should I get the parts? Ebay? New? Where's the spot?

Anyone got exact part #'s I should be looking for? I want to make sure I get the right stuff since I see some folks have mixed 4.10s/4.11s, etc.

Thanks!

EDIT: Forgot to mention I think I've convinced myself that a Powertrax No-Slip is probably the right auto-locker for me. Willing to talk about Detroit locker (since I'll be paying for a setup anyhow) if there's a compelling argument, but I'm not sure I wheel hard enough to justify it. Would go straight to a selectable locker if one were available, though.

[mdmead]

Are you sure you don't want to upgrade the rear axle at this time? I think the front is adequate most of the time, but I was disappointed in my rear axle in stock form. It started making noise before 50K miles and then was rebuilt before 100K. And I wasn't doing anything more than towing a 2,000 lb trailer around a few times a year during the winter.

Add in bigger tires, steeper gears, and a locker, and then take the family to remote parts of the desert, I'd be thinking seriously about an upgrade.

At one time there was some discussion on using a Ford 8" axle out of a fullsize van; as I recall it has an offset pumpkin and while not the stoutest axle available, is used as an upgrade by some of the Jeeping crowd. Seems it might be an affordable solution if it is close in all the needed dimensions.

[Herbie]

If I could be reasonable sure I could find an axle that would fit without much hassle, then sure. The problem is that I've been periodically poking into that for years now and the list of axles that may fit is already exceedingly short - the chances of actually finding one in a yard or wherever starts to look like a unicorn hunt.

I'm not ruling out ever doing it, but at this point, I'd really like to stop having to struggle up hills or to get onto short freeway on-ramps with my 3.42 gears...

[Captn. Crunch]

One stop shopping

https://www.yukongear.com/diffside.aspx ... Safari+Van

I searched http://www.car-part.com/mobile/ for a front diff for a 96+ five speed 4x4. That will be the cast iron version of our front diff. I found one shipped for $250.00. It was from a zr2 so it came stock with 3.73's to match my original ratios. If you were to swap to 3.73's a fresh set of bearings and seals takes care of your front upgrade. 4.11's will of course require a full on rebuild and set up.
The rear end we were issued is somewhat "petite" but with all of 200hp flowing out of our 4.3's, grenading a rear end is somewhat rare. There is flex issues but they can be beefed up with aftermarket axles and covers and whatnot.
Having a shop that specializes in setting up differentials, while probably pricey, will go a long way in guaranteeing a long and happy trail experience.
Just remember to follow manufacturers break in instructions to the letter. The heating and cooling process is vital to longevity

[Herbie]

Thanks Cap'tn.

Yeah, adding up the cost of custom or semi-custom rear-end solutions starts to get ugly fast. Just about every option I find for something that could fit will either require a different wheel pattern/axles, or a disc-brake conversion, etc. Bare minimum of welding perches, etc. doesn't bother me, but trying to put together a whole assembly that will bolt in starts to turn into significant money.

I'll take your advice and hunt for an iron front diff - that's one upgrade I think I can justify.

EDIT: Follow up question for you, Cap'tn: Do I need to worry about ABS on the donor part? (i.e. if I want to keep my ABS, should I source a front diff from an ABS truck?), or can I transplant over the needed bits? Only ask because the ZR2 diff nearest to me on car-part is listed as "No ABS".

2nd EDIT: Or does ABS even touch the diff? Now that I'm thinking about it I thought the sensors were in the hubs...

[Herbie]

Well, mdmead got me to spend one more day thinking about an axle upgrade. My findings in my axle thread here: http://astrosafarivans.org/bb2/viewtopi ... 989#p97989

Short version: Still no perfect option. Probably sticking to original axle and just doing the innards...

[Captn. Crunch]

Or does ABS even touch the diff? Now that I'm thinking about it I thought the sensors were in the hubs...
I'm not 100% positive on this so don't hold my feet to the fire but no abs may coincide with the axle change from bolt on to slip in axles on the 7.2 front diff. The early style flange/bolt together axles are somewhat preferred in the off road community due to the ease of change out if one where to break an axle on the trail.
Speaking of axles, I'm sure you are aware that when replacing axles you are best served buying NOS or rebuilt units. The metal in the genuine GM units is FAR superior to what you will find in new aftermarket units. There are some great articles online on how to rebuild the cv joints and how to deburr for added degrees of operation before binding. It's on my list but not very high on said list so it is just another bit of info I am passing on
I am also not sure but I think you can use flanged axles and abs hubs together. Sorry but it seems I'm just giving you more homework. The aforementioned combo would probably be the best possible mix and match setup with ease of replacement and abs activation on those loose downhills.
On word of warning. Make sure you are in low gear in 4lo on those loose downhills. When the abs kicks in you REALLY want engine braking backing you up. Ask me how I know...
Never mind-don't ask

[Captn. Crunch]

Just some more food for thought...

http://www.ebay.com/itm/like/3816989294 ... noapp=true
This one is for traction control equipped but if you look you can find one without. Sorry but I just went back and looked at the link I had posted originally and it wasn't for your year.
This is a Torsen style carrier for our rear ends. I have an eBay unit in mine and absolutely love it. It just works. No switches no wires no air lines to get ripped out leaving you with an open rear end at best. Serious off-roaders don't like em but the govmnt put em in hummers for years. You just need to touch the brake pedal if you get a wheel in the air. You can also purchase the same style carrier for the 7.2 front diff. It is the only option on the planet other than the Powrtrax locker which is less than ideal with our spindly little lawn tractor front diff.
I have yet to incorporate the front Torsen into the cast iron diff and place it under the van but I'm getting there. Twin torsens and low range should provide unpresidented traction coupled with impeccable road manners. Especially with an S-10 front axle disconnect to create a totally neutral front end until traction is required

[mdmead]

Well, mdmead got me to spend one more day thinking about an axle upgrade. My findings in my axle thread here: http://astrosafarivans.org/bb2/viewtopi ... 989#p97989

Sorry!

[Herbie]

Does anybody have strong feelings about the relative quality of different ring/pinion suppliers? I see Yukon Gear and Richmond at close to the same price for the rear set, but with Richmond slightly more.

It's a little hard to sort out online reviews since there's so many sets for different applications and I'm not sure that the issues with Yukon Gear sets for a D60 apply to us, for example.

Also, does anybody besides Yukon make a set for the front? I was surprised to find that Richmond does not.

EDIT: Looks like Motive Gear also makes a front set, but there's a HUGE price difference (i.e. they're much cheaper), which sort of worries me about quality...

[Herbie]

I searched http://www.car-part.com/mobile/ for a front diff for a 96+ five speed 4x4. That will be the cast iron version of our front diff.

Hey Captn, what was your secret for getting people to sell you a part via car-part? I've sent out three requests for quotes and heard NOTHING back from any of them.

Also, can anyone educate me on the differences between the GM 7.5" and 7.625" diff housings? I've been looking at tossing in a beefed up diff cover or cover/girdle while I'm having the rear axle done. Some places list the 7.5/7.625 as interchangeable, others only list one or the other. Do I need to find something 7.625 specific?

[Captn. Crunch]

I just submitted a query for a cast iron front diff on usedcars. Let's see what happens. As far as the 7.5 vs 7.625 don't quote me but I think they went from 26 to 28 spline and the ring gear increased the .125. The housing hasn't changed

[Herbie]

I just submitted a query for a cast iron front diff on usedcars. Let's see what happens. As far as the 7.5 vs 7.625 don't quote me but I think they went from 26 to 28 spline and the ring gear increased the .125. The housing hasn't changed

Cool, yeah I found a couple of other listings where the sellers are very explicit about the cover interchanging 7.5 vs. 7.625. Got a TA Performance girdle/cover on the way. Have got all my bids from local gear shops so I know who I'm having do the work, and he feels good about parts availability. I may even try to get the gearing gone between my next two trips! (Unless I get a line on an iron case, in which case I'll wait for that)

[Captn. Crunch]

And all the while.... By the way, what ratio are you looking at? All Zr2's came with 3.73's so if you were going to re-gear and 3.73's were enough and you got a cast iron Zr2 unit, you would be halfway home. Well halfway home if you don't count the perfunctory freshening up on the acquired diff or the swapping out of said diff. But seeings as the front has got to come apart anyway you look at it. They sure didn't make em user friendly. Therese no getting to those gears without splitting the case and that's not happening while still in the truck

[Herbie]

I've convinced myself that I do enough driving up and down mountains that the 4.10s are the way to go. The extra scratch for the ring and pinion isn't too bad.