Chevy & GMC Vans

cleaned the case surfaces, RTV, bolt up and ready to install

Finally got the front dif. installed. I don't have the 4.10's in the rear so I couldn't test it under load. But I did run it in 4x4 with the front axle disconnect (s10) disengaged: quiet! So far so good.

Awesome. I should get to my front diff sometime in September...hopefully!

Thanks for your help Dean. I now have a set of used OEM 4.10s and a new Truetrac waiting to install in the rear!

What did the 4.10s do for your mileage? Also what is the S10 front disconnect? Sounds like a worthy addition. I think the 4.10s would be a big improvement for my van. It has the 3.73s but with taller tires it seems to struggle a little.

The S-10 disconnect is a splined sleeve that disengages the passenger side axle only. Between that and the 4.10s, it doesn't seem to have improved MPG at all. I keep very detailed records with every fill-up, but I can't say for sure how accurate my conversion factor is or has been in the past.

I used to use (I think) a multiplication factor of 1.2 for the bigger tires. Now, with the tires and new gears I use .09 as the speedo reads fast.

For certain it improved the drivability especially in the mountains. It pulls the grades with much more power over my stock 3.42's. I would do it again.

This is more a curious question than anything that is based off what I knew from the reason why Peter did the 502 BBC swap.When he had the 4.3 in the van even with gear changes,he would go wheeling with lifted and Lockdoc and the tires he had just killed any power he had and he would be getting stuck all the time.So the question I have is if tire sizing doesn't reach a point of dimensioning returns on a gear change??. If a smaller tire size wouldn't be better to keep the 4.3 into it's power band better??. .I knew that Lifted with a Pickle bus had some gear changes,but I don't recall is those where not 4.56's that let the larger tires work so well with a 4.3.

Did Peter have low range? I can't imagine any tire that would fit an Astro tire well being too big for lowrange and a 4.3. I've run 33's and stock gears on my old Toyota 4 banger and never been stuck due to lack of power.

Peter did not have low range and he had stock 3.42's when he wheeled the 1 time with us. I had 4.10's in the SPB but wished I had 4.88's or 5.13's. I stuck with 4.10's as that is what the Dana 60 had so I didn't have to regear.

Just want to say... I googled "4.10 Gears Astro" and this was the first or second google hit. This site pops up about 60 percent of the time on astro google searches. Fun stuff.