Another Gear Ratio Thread...

[Opeth]

Gary's is up here by me in Oneida, well oneida is about 45 mins away but I call it close. They've come through for me numerous times.

Let's meet up and go picking!

I'm game if I have the day off, not sure which weekend day I have off every week. It's one downfall of my job.

[Cable810]

for the front, I think you want the Front Axle Assembly (w. Housing).
The Differential Assembly (with Carrier) makes me think more along the lines of just the internals.
Also when you search you see some results for front and others for rear.

Ok I'm getting close on purchasing the Axle and Front differential. Just one last thing. I'm still lost on the Front Differential with the list below. The Front Axle Assembly(W.Housing) is the only thing that renders a Gear Ratio. My question is whats the difference between 1Rr oil pan mtg hole and 2Rr and what one do I need??

1 Rr oil pan mtg hole (by yoke), 3.42 ratio GU6
1 Rr oil pan mtg hole (by yoke), 3.73 ratio GT4
1 Rr oil pan mtg hole (by yoke), 4.10 ratio GT5
2 Rr oil pan holes (by yoke), 3.42 ratio GU6
2 Rr oil pan holes (by yoke), 3.73 ratio GT4
2 Rr oil pan holes (by yoke), 4.10 ratio GT5

[The Roadie]

All front diffs have 2 yoke mounting holes. The choice of 1 or 2 is a data base error caused by GM's goofiness. Same root cause as the 140-150 A alternator question when you go to buy a serpentine belt, when the REAL question should be "Do you have a short or long wheelbase?"

[Cable810]

So according to your post I would need 2? Thanks Roadie! !!

[Cable810]

After much reading I have come to a different conclusion Bill. It seems that there is a slight difference and that slight difference bieng that the 1 Rr oil pan mtg hole (by yoke) only lists 2002 Trailblazers, Envoys etc... and the 2 Rr oil pan holes (by yoke) lists 02+ and the price difference. With that being said I'll be fine with gettting a 02 Carrier Assembly(1 Rr oil pan mtg hole(by yoke)?

Cause according to this I should
http://gmtnation.com/f79/front-carrier- ... 73-a-1366/

Anyone??

[The Roadie]

I may have misremembered it. Sorry. Whatever you can get will fit.

[Shdwdrgn]

Since I'm actually looking into this myself, I wrote up some code yesterday to make an interactive chart for various gearing and vehicle speed. I made the assumption that overdrive is 0.7:1 (collected from another Chevy site), but assuming that is correct, all the data on this page should be just about perfect. Based on this data, it made it very obvious to me that I want to go with the 4.10 gears, rather than the 3.73's (I currently have 3.42's with 30.6" tires and do a lot of in-town driving).

If anyone else is interested... http://www.sourpuss.net/projects/vehicl ... arcalc.php

This really makes me question why GM even offered the 3.42 gears? The only way I can see them actually being beneficial is in a situation where you drive almost exclusively out on the highway, in locations where there are no hills or wind to offer resistance. My drive in to work is fairly flat, but I see a lot of wind coming off the mountains. I've found I get better mileage by leaving it in 3rd.

[HARDTRAILZ]

How fast is your drive? I see huge differences in 60 to 80 mph extended driving.

[Shdwdrgn]

65 tops, but with rush-hour traffic its usually more in the 55 range.

By the way, I found the info for the GM 4L60-E transmission, and have updated the gear ratio page. 1st=3.059, 2nd=1.625, 3rd=1.000, and 4th=0.696. I made the page so you can specify what gear you want to see the RPMs listed for, and if I happen to find the ratio for 4LO I will add that option into the page as well.

[fishsticks]

r 4LO

2.7:1

[NC_IslandRunner]

Definitely skip 3.73 and go straight to 4.10s, I'll be looking to get 35's after my current tires wear out but want at least a 8.6 rear axle and 4.10s, A friend keeps trying to get me to SAS, He has most the parts already and would do it cheaper than anyone else I know. If I do I'll be going bigger than 35s but that gonna be a while.

[Shdwdrgn]

fishsticks - thanks for the 4LO info, I'll get a checkbox added for that option today...

I currently have 30.6" tires (265/70-16) and I probably won't go any larger than 31's. I do a bit of non-aggressive off-roading, however I do tow a 5500# trailer up the mountain into Estes Park, and otherwise 90% of my driving is in town or 55mph and below... So yeah, I think the 4.10'ss are looking like the perfect choice for my use.

So if memory serves me correctly, I can get an 8.6" rear off of a 2002-2005 EXT, which should be a direct bolt-up to my 2004 SWB, which not only gives me a stronger axle for towing, but also saves me the trouble of having to re-mesh the new gears?

Then I am just left with changing gears in the front, for which I've seen almost no info about. I assume there is also a differential in the front axle, similar to the rear, where the gears are located? Is there something here that can also easily be swapped out, or would I be better off just buying a set of gears and pay a mechanic to swap out and properly set the gears for me?

[fishsticks]

viewtopic.php?f=27&t=1351

[Shdwdrgn]

Actually been reading that one... I'm about half way through it.

Also, updates to gearcalc are done to include 4Lo.

[Shdwdrgn]

Have you had any luck finding front diff parts? I'm looking for some 4.10's, and not finding squat. I can''t even seem to find anyone just selling the ring&pinion gears (of course I have no idea if I just need the gears, or if there are other parts that have to be changed out as well?)...

Anyone know of good resources other than car-part.com?

[EDIT] erg! I just realized I was responding to a post from the first page of the thread. My brain is mush.

[navigator]

you can get new gears from
ringpinion.com

[Conner299]

Summit racing has ring and pinions as well as eBay. Don't know about eBay quality though. IMHO, if changing ring and pinion, an axle rebuild kit might be worth a look as well.

[Shdwdrgn]

Thanks for the info. My goal is to find an 8.6" rear axle that already has the gears, but a rebuild might be worthwhile in that as well. The only one I've found so far has over 215k miles on it.

For the front end... I'm still looking. Like I said, I have no clue if I need any parts other than the ring and pinion gears to make the swap. I just know these 3.42's are killing me.

[fishsticks]

I got my gears off ebay. They sell all the major brands there.

Front gears are GM 7.25" reverse cut, same as the S10.

[mikekey]

So if I have this right, I should be able to move from 3.73's to 4.10s without having to swap a pumpkin, but if I want to move up to 4.56 gears I'm going to need to find myself the rear from EXT?