ReGearing a V8?

BlackWorksInc

BlackWorksInc

New member
So this is just one of those sort of random thoughts that popped in my head... But if you were to Regear a V8 4th Gen, would you benefit more from regearing the transfer case Differential or would you have to do both front and rear axles? I woudl figure with the way the system distributes power and such that you need to do both front and rear axle if you're regearing... but I wonder If you could regear the center diff instead of having to buy two seperate Ring and Pinions.

I don't remember ever seeing this mentioned before so I figured I'd pop it up here.
 
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I'm unsure regearing the torsen T-3 heres some technical data

Torsen T-3 Differential

It seems like it would be cheeper to regear the front and rear axles there third members so you can just pull out the carrier housings and take them to a drive line shop or do it yourself. ring and pinion sets range in price 180-500 from what I've seen Yes if you regear the rear you need to regear the front. I think with the torsen T-3 center differential transfer case in theses trucks as long as your transfer case locker isnt engaged i believe the center differential will make up for ratio differences but you would probably be causing excess wear that can be avoided. And i could be completly wrong and its a must to regear front and rear axles at the same time.

I'm also interested in regearing my V8 and have not had much luck finding gears called out for my specific truck I can find ring and pinion sets for V6's all day. From my research on my truck (2003 toyota 4runner limited 4wd V8) it came stock with xreas and the AWD driveline contains 8" Ring gears front and rear with matching 3.73 gear ratios I was told this was different from V6 drive lines as well as Tacoma drivelines. Thats all I know I'm hoping this thread will shed some light for us.
 
Yeah, I figured the central diff was going to be more diffficult to do. When I have some time at work (and when our network gets fixed...) I will have to see if I can pull some information off TIS for this thread.
 
Bump.. anyone have any input on this still interested in regearing lol thanks i suppose i could blindly walk into a drive line shop and perhaps get ripped off but i wouldnt think my toyota buddies would let that happen lol
 
I don't think there is a difference between V6 and V8 diffs.

If you want to re-gear in the transfercase you could look at something like this adapter plate. Then you bolt on a gear drive transfercase from an older 4runner and change the gearing on that. Your 4hi remains the same for street driving, only that your 4lo can get very LOW with the proper gearing.

2000-2004 2UZ-FE 4.7-liter V8 drivetrains | Marlin Crawler, Inc.

It is listed for 4.7 2000-2004, other companies make adapter plates too. I have seen this on old generation 4runners and a V6 4th gen. So not sure how this really reacts with a AWD V8 4runner.

Eventhough, I would probably stick to regearing the diffs first, since that gives you the power to spin bigger tires for regular street driving where you need it most.
 
there are differences in the V6 and V8 drive lines they both have 8" rings yes but the V6's have 3.93 ratios and the V8's have 3.73's. The question at hand is do they share the same axel spline count, as well as the same pinion shaft diameter, Are the cariers interchangable between the two? I know the V8 has no sycronizers for the center diff lock and the V6 does the V8 aslo doesnt have a front diff that disconnects. I believe the V6's automaticly dissengage the front axel and locks the center diff when in 2wd mode. Yes the half shafts turn with the wheels but the front drive shaft doesnt spin when the V6's are in 2wd. This tells me the front carriers in the V6's have some differences compared to the V8. I havent had the pleasure of venturing into my rearend. (haha that sounded funny or even better thats what shee said!!) So I dont know for certain I have a contact at toyota that if i take the time to go see should be able to clear alot of this up for me but i havent taking the time to go into town in a while i live about 45 minutes from the closest dealer.
 
aha2988 said:
there are differences in the V6 and V8 drive lines they both have 8" rings yes but the V6's have 3.93 ratios and the V8's have 3.73's. The question at hand is do they share the same axel spline count, as well as the same pinion shaft diameter, Are the cariers interchangable between the two? I know the V8 has no sycronizers for the center diff lock and the V6 does the V8 aslo doesnt have a front diff that disconnects. I believe the V6's automaticly dissengage the front axel and locks the center diff when in 2wd mode. Yes the half shafts turn with the wheels but the front drive shaft doesnt spin when the V6's are in 2wd. This tells me the front carriers in the V6's have some differences compared to the V8. I havent had the pleasure of venturing into my rearend. (haha that sounded funny or even better thats what shee said!!) So I dont know for certain I have a contact at toyota that if i take the time to go see should be able to clear alot of this up for me but i havent taking the time to go into town in a while i live about 45 minutes from the closest dealer.
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Pretty good point, forgot about that. But didn't they then all go 3.73 in 2004 or 2005.

When I was looking at this a while ago for mine, I had found nitro gears made a version of 4.56 gears for the front clam shell with 3.73 carrier.

Or you can put an arb locker and choose between 3.73 or 3.90 carrier according to the gear and possibly brand you want.
 
only the 4 speed v6's had the 3.90 gears 03-04. The 5 speed 05+ has the 3.73 like the v8's. You would definitely want to re-gear the axles and not the center diff. It is too complicated and not really serviceable. The 6 speed FJ's have the 3.90's in them as well. So, the v8 guys could move to those which would help. I think 4.10's would be the sweet spot for 35's personally. Not sure if anyone makes them though.
 
yeah I'd like 4.11's personally but I cant find them specific to my truck. as for the arb thats the plan im headed for. however changing the carrier doesn't do much if the pinion shaft diameters are different which is still the unknown aswell as spline counts of all shafts.

btw: I'm def talking about regearing the diff's f/r.

why do all the ring an pinion set distributors specify the sets to be for a V6 specifically and not say oh this will fit a V8 aswell?

I don't have a particular brand in mind I do kno I want the ring gear cut thick (apposed to thin teeth) but I don't know what that means as far as my search is concerned. I don't want to change my transfer case or adapt to a different one I just want to put in a set of gears that later I can put a ARB locking carrier into I'd do them both at the same time but ive got a budget to contend to. next free chance I get I'll dig up some real info on these axels and diff's and see what I can find there has got to be a reason I can't find vehicle specific gear sets for an 03 V8
 
If you are planning on doing the work at a shop, setting up the gears can run as much as 500$ish each. It is a job that few people want to tackle themselves.

The arb is not a simple drop in, so you would need to reset the gears again and pay twice. Consider getting all the parts first then doing it once.

I also never found 4.11 in my search.

I bought 2 arb lockers to use on my 4th gen, but I never ended up doing it to mine, I locked up a first gen instead. But based on conversations with the guys at East cost gear supply not much else was needed but the arb and gears.
 
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well I plan on doing the job myself fortunately so no worries of paying twice just twice the labor time. im not above waiting and saving so it's probably in my best interests to collect up all the parts and do it at once. there isnt much else needed. besides gears and carriers other than a ring&pinion master install kit it has seals and shims and spacers and what not per axel of course to set the gear backlash and bite pattern it was an overwhelming job the first time I tackled it but it's not to crazy once you get familiar with the process I've found 4.11's for V6's just nothing specific to the Toyota V8 drive line which is why I question what differences there are in the two driveline setups
 
It's my understanding that the v6's and v8's have the same axles and gear assemblies. So you should be good with looking at the v6 gears. I haven't personally taken them apart to inspect each but check with toyota and see if the part numbers are the same for ring gear for the v6 and v8...if they are then just go with v6 gears. I know lots of fj guys that have regeared so it shouldn't be an issue for the v8 guys at all.
 
The front carrier is different on the V8. They do not use the axle disconnect with the full time 4x4. I do not know if the gears are the same but I think they are.
 
I'm curious why so many v8 guys think they actually need to regear, unless your runnin 35+ tires I just don't see a point to it. Even with my setup (35's) I have no plans to regear until I up my tire size and get my sas - and I wheel my rig pretty hard. Maybe I'm missing something but the v8 has more then enough power to turn the tires and IMO the weekest point in the drive train, other then cv's, would be the transfer case.
 
Huskey said:
I'm curious why so many v8 guys think they actually need to regear, unless your runnin 35+ tires I just don't see a point to it. Even with my setup (35's) I have no plans to regear until I up my tire size and get my sas - and I wheel my rig pretty hard. Maybe I'm missing something but the v8 has more then enough power to turn the tires and IMO the weekest point in the drive train, other then cv's, would be the transfer case.
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I Haven't found much need for regearing off road its mainly towing i would like the gears for. The gears would certianly help me charge up a few hill climbs but other than that its more of an acceleration preference as well as i do plan to go to bigger tires. I mainly need to lock up my rear axel or use a true trac carrier that has been my weak point of road, i'll pick up a tire and then just the tires with the least amount of traction spin. Also I'd like to think that in regearing i can get the peppyness back i once had with smaller factory tires.
 
I see your point to want to regear for towing something real big, but as for charging up hills, unless your on 35's with both front and rear aftermarket bumpers, a tire carrier, and a full tank of gas, the V8 still takes care of that for you. As for the peppiness, you don't miss it on the 35's. The amount of power loss is not as much as you would think, and I concider the minimal loss a safety factor for the substantial lift with the bigger tires. No need to have a jacked up rig too peppy.

IMO, gears should be one of the last mods you make with a V8. The locker should be one of the first, after lift and tires of course.

Just my 2 cents
 
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