Front & Rear 4.10 Diff questions

Post by **Walt** » Mon Dec 13, 2004 8:52 pm

Hey everyone, my wifey said I could get a 6" SL if I lost some weight (not going to say how much)

.

Anyways, I know that I'll be in trouble if I try to run 32"s or 33"s with a 3.73 ratio, so I want to go ahead and swap to 4.10.

I would need a new front diff and a new rear diff or rear axle correct? Would it be better to find a rear diff, or a whole axle for the rear?

I'm fairly sure this will probably void any drivetrain warranty that I have right?

Anyways, any ideas as to where I could get these items? Also about the cost involved?

I think I could swap the rear fairly easily in a few hours, but the front might be a bit tougher.

If anyone knows of anything else I need to be aware of, please post! Thanks!

killian96ss · Post by **killian96ss** » Mon Dec 13, 2004 9:18 pm

All you need is new front & rear ring and pinion sets with install kits and about $700-$1000 for someone to install it unless your going to do them yourself. If you want a different posi or locker in the rear this would be the best time to do it. The rear could be done in a couple hours with the right tools, but the front seems to be the most fun.

This will definitely void the drivetrain warranty.

If you could find a way to make a rear ZR2 axle work that would be cool as they are much stronger than ours (7.65 vs. 8.5). I've also heard the front diffs are stronger as well, but I don't know what the upgrades are.

Steve

Post by **Walt** » Mon Dec 13, 2004 9:29 pm

I won't be doing any real offroading, I just want to go up

This website: http://www.accuautoparts.com has gear sets that should fit our trucks (enter your vehicle info first). They list front and rear diff parts, for almost any ratio, from several different manufacturers.

For front and rear 4.10 sets from Motive around $300.

Front and Rear 4.10 sets from Precision Gear around $450.

Are these any good. I don't know everything on the subject, so if a couple of you more knowledgeable folks could check that site out for me, and let me know if it's worth messing with, and also what I need, I'd appreciate it.

Can the new gear set be swapped into the Diff case? Or will I need a new front and rear case?

Would I need to buy anything else other than just the Ring and Pinion gearset from that site for the front and rear?

Thanks!

Rusty · Post by **Rusty** » Tue Dec 14, 2004 4:44 am

killian96ss wrote:I've also heard the front diffs are stronger as well, but I don't know what the upgrades are.

Steve

I looked into this back when I was looking at a V8 swap (before I thought about SFA) and from everything I read the ZR2 has the same front diff (7.25") as ours. Now some Syclones/Typhoons and the rare standard S-10 had a cast iron case version with the same internals as ours that would be somewhat stronger, at least as far as the case goes, but good luck finding one.

a2b · Post by **a2b** » Tue Dec 14, 2004 9:24 am

just go to the nearest rear end shop. it will cost you about a grand to get the gear change done. they will not like your for it either. our trucks are really hard to work on, the front diff that is.

also, zr2 has the same front as us, and the zr2 rear housing wont fit on your truck. strength isnt an issue cuz your front will break long before your rear will

bubaloo1983 · Post by **bubaloo1983** » Tue Dec 14, 2004 9:28 am

i did my lift and gear swap at the same off road store. they did it cheape seeing as the whole front end was apart when they did the lift anyway.

the total bill came to 3000 grand after lift and gears. thats canadain mind you

they said it was the best way to go if you had the money all at once
maybe you could look into tha?

coffeedrnkr · Post by **coffeedrnkr** » Tue Dec 14, 2004 9:44 am

EDIT: I have changed my previous statement to now say if you have the time and energy to do it yourself, it isn't impossible and I could give you some pointers. BUT otherwise go ahead and take it to a shop so you don't have to worry about any problems that may come up.

back to subject though I do not think I would drive my blazer without the 4.10's it would take forever to get going. you do not have to change the whole axle just the ring and pinion.

If you do have it done definately have them do the gears at the same time b/c you have to practically disassemble the whole front end to get the differential out of there. I thought the front was Extremely easy to reagear, the only thing you have to do is but the old pinion shim on the new one with a new bearing and then change the ring gear and bolt it back together.

killian96ss · Post by **killian96ss** » Tue Dec 14, 2004 9:47 am

wamason wrote:For front and rear 4.10 sets from Motive around $300.

Front and Rear 4.10 sets from Precision Gear around $450.

Are these any good.

Both are good companies. At $150 cheaper, Motive sounds a little better.

Would I need to buy anything else other than just the Ring and Pinion gearset from that site for the front and rear?
Thanks!

Install kits with new bearings, shims, crush sleeve, etc. Are you doing this yourself or having a shop do it? If you are doing it yourself you will need the right tools.

Steve

Rusty · Post by **Rusty** » Tue Dec 14, 2004 10:03 am

coffeedrnkr wrote:back to subject though I do not think I would drive my blazer without the 4.10's it would take forever to get going.

The '89 Blazer I have now has 3.08's. I was going to put 31's on it until I found out what gears I had. I think I'm staying with the stock tire size for a while.

killian96ss · Post by **killian96ss** » Tue Dec 14, 2004 11:54 am

Here is one reason why I thought the ZR2 front diff was upgraded or stronger than ours. This is an option package for a 2005 Blazer on one of those build your own vehicle pages @ www.gmbuypower.com CHASSIS PACKAGE

Suspension Package, 4x4 Wide Stance Sport Performance, includes revised wide-tread frame, strengthened front differential gears and drive axles, large bearings and longer, larger rear axle shafts, revised multi-leaf springs and added rear axle track bar, front stabilizer bar, Bilstein gas-pressurized shock absorbers, (ZM5) Skid Plate Package, outside Tailgate mounted spare tire carrier (ZR2) $2,000.00

Steve

Post by **Walt** » Tue Dec 14, 2004 12:20 pm

I had considered doing it myself, when I did the lift, BUT, finding someone to do some welding might be a bit tough (the SL kit requires minor cutting and welding on one or two parts right?).

I can do something given proper instructions, but I don't have alot of heavy duty tools available like air tools or a lift.

a2b · Post by **a2b** » Tue Dec 14, 2004 1:55 pm

coffeedrnkr wrote: all you need is a 40 dollar backlash gauge and you can do it yourself, and there is no replacement for how much you will learn if you do the lift yourself.

along with more tools and the "know how" than 99 percent of the people on this board dont have. be careful of the advice that you give.

ring and pinion is not something to play around with. if you have a spare vehicle and wanted to learn on it, then go ahead..but i am sure he wants his vehicle back up and running and without problems. defintely do the lift and the gears at the same time. but it will have to be at the same shop cuz you have to get the entire rear end to shop to change the gears. you cant just take the diffs out and take them over to the rear end shop.

Post by **Walt** » Tue Dec 14, 2004 2:53 pm

Got a problem, the only shop within 100 miles of me does not do gearing at all. They'll install a lift if purchased from them, but they refered me to another company to re-gear, and they charge $1200 for the parts and installation, plus the $650 the lift place charges to install the lift..... Guess I'll have to keep looking for somewhere else to get it done. Also, with the superlift kit, will I have to get any driveshafts lengthened?

Rusty · Post by **Rusty** » Tue Dec 14, 2004 3:53 pm

killian96ss wrote:Here is one reason why I thought the ZR2 front diff was upgraded or stronger than ours. This is an option package for a 2005 Blazer on one of those build your own vehicle pages @ www.gmbuypower.com CHASSIS PACKAGE

Suspension Package, 4x4 Wide Stance Sport Performance, includes revised wide-tread frame, strengthened front differential gears and drive axles, large bearings and longer, larger rear axle shafts, revised multi-leaf springs and added rear axle track bar, front stabilizer bar, Bilstein gas-pressurized shock absorbers, (ZM5) Skid Plate Package, outside Tailgate mounted spare tire carrier (ZR2) $2,000.00

Steve

Hmm, interesting. All I know is everyone I've heard says they are the same front diff. I just know I have the "not so good" ones! Oh well.

Post by **Walt** » Tue Dec 14, 2004 4:08 pm

OK, been doing some thinking. I know of someone who can weld, and from what I know, the SL kit requires very little welding and cutting, so I think I could handle that. My big question is: If I had a shop, and a couple of weeks to install this kit myself (possibly with the help of a friend or two), could I do it with basic DIY knowledge and instructions? I could probably take both diffs out when I get to them, and take them somewhere to get the gears swapped. Any thoughts on that?

Thanks!

Rusty · Post by **Rusty** » Tue Dec 14, 2004 4:34 pm

wamason wrote:OK, been doing some thinking. I know of someone who can weld, and from what I know, the SL kit requires very little welding and cutting, so I think I could handle that. My big question is: If I had a shop, and a couple of weeks to install this kit myself (possibly with the help of a friend or two), could I do it with basic DIY knowledge and instructions? I could probably take both diffs out when I get to them, and take them somewhere to get the gears swapped. Any thoughts on that?

Thanks!

Let's put this into perspective: There are people on S10Extremist that have successfully done "homebrew" SFA conversions on their S10's with not much more than "DIY Knowledge" (and some welding skills) and most of them came out pretty well from what I've seen. I think you can probably do it yourself.

weaselmf · Post by **weaselmf** » Tue Dec 14, 2004 6:06 pm

There are some parts that must be aligned correctly so be very careful and take your time..... I would not plan to have this thing completed in a weekend, unless you have lots of help. As for the gears, Get them done by a pro! If you don't get them installed correctly, they will crater on you and then you have some real expensive problems. I have been thinking about installing a lift, but the more I read about them the more nervous I get. However, I am no welder...

coffeedrnkr · Post by **coffeedrnkr** » Tue Dec 14, 2004 8:01 pm

along with more tools and the "know how" than 99 percent of the people on this board dont have. be careful of the advice that you give.

Sorry

, maybe it is just me but I did my gears for the first time ever on my truck when I did the lift and have never had any problems. Then again I always say do it yourself but I am only 18 and probably have more energy and time to do this stuff than the rest of you do, oh ya and another reason is whenever I am putting new stuff on that usually means I am broke from buying it and have to do it myself anyways.

I take back my last post to say if you dont have the time or energy, and have the money for somebody else to do it, by all means have a shop do it and let them deal with the problems .

Post by **Walt** » Tue Dec 14, 2004 8:12 pm

I'm sorry if I missed the answer, but does the lift require longer drive shafts or anything?

Also, I'd probably attempt this install over the course of about 2 weeks in a friends shop.

Once I get the front end apart to install the lift, I plan to take the Diffs to a friend who works for a chevy dealership and pay him to re-gear them. If I buy the Motive gears for about $300 for both, and pay him $200 on the side that comes out to only $500 bucks for a re-gear

hopefully.

Also, I know not many of you have this kit, but I'll need all the tips, tricks, and hints I can get. If you have some advice, or experience, or have installed this kit, let me know here

Thanks!

coffeedrnkr · Post by **coffeedrnkr** » Tue Dec 14, 2004 8:27 pm

don't get too exited about the lift don't you have to get the weight loss approved by the "wifey" first

hehehe

No, I don't have the 6" but a couple tips is make sure to measure the distance between the control arm bushings and then measure the drop brackets to make sure they are the same distance apart and will work, do this BEFORE you drill holes. This little mistake cost me like 2 hours more work.

hmmmm, otherwise just have a BFH on hand when you need to beat the snapple out of something. also go into it in the frame of mind that it isn't going to go as easy as you planned.

a2b · Post by **a2b** » Tue Dec 14, 2004 10:15 pm

no you missed a point. the whole reason you have to get the shop to do the lift and the gears is because you cant take the rear diff out. its a 10 bolt. you would have to take the entire rearend to a shop. BUT, you could take the front diff out and go get the gears changed. the come back and lift it, then drive the truck in 2wd ONLY, then drive the lifted truck over to the rear end shop and get the rear end gears changed. this way, you will save on labor for the front end and it will be the same as one shop but with an extra stiep but no extra labor charges......

coffeedrnkr · Post by **coffeedrnkr** » Tue Dec 14, 2004 10:41 pm

well, a2b your idea is probably more logical but while he is putting on the lift the axle will have to be unbolted from the leafs anyways couldnt you technically take off the calipers and hard line clips and take the brakes off of the axle but remain on the truck as a whole so you dont have to disconnect them, then unbolt the breather hose and disconnect the e-brake cable (which has to be done anyways) and the axle would be free to load up in another truck and get regeared?

I am pretty sure that would work, it doesn't sound like too much extra work in theory other than a couple plastic clips and some bolts, then he could get both regeared at the same time (if that makes any difference as far as scheduling, idk)

oh and you do not need a new rear driveshaft, I would think with a 6" you would need a new front one though b/c I eventually had to get one on my 5" TM lift. but I am not sure on that one though.

a2b · Post by **a2b** » Wed Dec 15, 2004 3:49 am

yes if you wanted to the do the whole rearend, naturally. you could just do that

it will be kind of heavy so dont throw your back out picking it up

Retep · Post by **Retep** » Wed Dec 15, 2004 5:32 am

a2b wrote:... the zr2 rear housing wont fit on your truck.

Why? I thought the measurement between the leaf spring mounting pads on the axle case itself was the same.

Post by **Walt** » Wed Dec 15, 2004 6:53 am

That's what I was planning to do, take the entire axle

Also, the SL kit doesn't come with a new front driveshaft does it? If not, will they have measurements or anything?

Thanks!