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Will I need to change out the 3.73's for 4.11's or 4.56's as I've got 35" tires.

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BPatrick

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My blazer has a 700R4 and came stock with the 3.73's. When the bigger tires go on, am I going to need to change gearing?
 
Well, you should change gearing, but are you keeping the 1/2 ton axles or did you upgrade already? Most will advise you to go to at least 3/4 ton axles before spending money on regearing, and then most 3/4 ton stuff is 4.10 or 4.56 already.:D
 
Thanks for the info...I haven't changed them out yet as the truck got back from the body shop in pieces and we partially put it together and then put on the Rancho 4" lift kit. Of course, I'm on a budget, so I'm trying to keep costs down. I'm not sure what the expense to change to 3/4 ton would set me back right now but I think I'll have to compensate for the 35" tires. I'm sure which to go with 4.11's or 4.56's.
 
It's about 150-200 bucks for a 14b rear, front may be a little more, and it'll be more like 500 just to regear your 1/2 ton rear. Budget is why I brought it up. My buddy ran 3.73 in his 'burb(700r4) with 37s for about a year, til the 10b blew up. It's not an urgent thing to change if you want to wait awhile. 4.56 would be my recommendation anyway.
 
Thanks for the information. It may til spring before I tackle this due to weather and lack of money until business picks up in the spring.
 
I swapped my 3.73 10 bolts for 4.10 14bff in my Suburban and run 33's. I did run 35's, but the 700r4 wasn't happy in OD. It kept kicking in and out of OD so I went back to 33's. I'd suggest 4.56's for 35's with an overdrive tranny.
 
Gone hunting...thanks for the heads up...I'm already starting to see that with 31"'s that I have on the truck on the stock rims...I use these to get the truck in and out of the garage and to get the truck aligned. What I've been doing is driving and manually after 50 mph shifting into overdrive, otherwise when the tranny is warmed up the truck rpm is way too low and it slows down going up hill.
 
There is no way I would pay to regear the stock 10-bolts from 3.73 to 4.10........1. it's a waste of money to do that on 10-bolts and 2. you really wouldn't notice the differece.

And I can say that because I went through this exact same thing a long time ago before I knew any better (replaced the 3.73's with 4.10's in the 10-bolts, but in my defense most of the cost was covered by insurance because the truck was stolen and they blew up the rear axle).
 
You really should go to 4.56 in whatever axle you choose to run .

But if you aren't wheeling , and your roads are relatively flat , you can use 3rd in town and 4th on the freeway just fine . Or leave it in 4th as I did , and just learn to lean into a little when it downshifts so it holds and doesn't hunt .

I ran 35's and 3.73's for almost a year before I went and got the 4.56's .
 
Here lies the issue of what I will do with this truck. I've done 3-4 trucks with the last one being a 1984 extended cab S-10 4X4 and put a 4" lift on it, it already had a 1" body lift that I left on as it helped fit the 350 under the hood and I put on 33's and with the independant suspension I really take this out and mess with it. I started building this truck to do the same and got so much money into it over the last 7 years(just like everyone else on here) that I don't know if I will pleasure drive this and keep it tamer for light off-road and keep the truck for more radical. Keep in mind living in Northern Indiana, we don't have mountains. I am tempted to switch to 4.56's but I don't know if I need to switch out to the bigger axles. I now understand the differences but I don't know if its worth the time.
 
Given your stated uses (and the rest of this conversation as input) I'd suggest looking for a good condition set of 4.10 3/4 ton axles. The cost to swap them in will come out less than regearing (as noted) and on the flat terrain you mention, moving from 3.73 to 4.10 may be JUST enough "oomph" to run your 35's with satisfactory performance.

FWIW, I'm in the same position with my K5... just went from stock 3.73 1/2 ton axles to a 4.10 14bff and 8 lug d44. I ran 35's on the 3.73s (granted, on a different tranny than yours) for a long time and didn't mind at all.
 
thanks desert yetti...ironically as I was junkyarding for some parts...the guy at the yard gave me a lead, without inquiring, on a 3/4 4x4 with a 400 engine built 30 over the motor is fresh. This truck is his buddies and he just wants to dump it...now I'm thinking bigger axles and better gearing...sometimes timing is just awesome. I'm going to test drive it this weekend and make sure there are no issues. For $500.00 I'll try to talk him down but I'd have a good spare motor, axles, the doors are in great shape and the tranny and transfer case...my wife just looks at me and shakes her head cause now she knows the garage isn't getting freed up.
 
Cool deal... if you can get a 3/4 ton truck with the 14b FF rear, a good d44 or 10b 8 lug front, and a strong 400ci for $500, do it! Anything else you pull off the truck is just icing on the cake!
 
now the question, where to put it. I think I'll leave it driveable for a while so it can move, yet another eyesore for the neighbors. when i move out to the country i wont have this problem. my front yard is city and backyard is county. I'll try to talk him down from $500 but still i don't think i'll go wrong on this one.
 
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