3rd Gen Axle Capacity and Payload Confusion

I find the axle capacity and payload numbers somewhat confusing on 3rd gen tundras, especially compared to 2nd gens. TO BE CLEAR, THIS ISN'T A 3RD GEN BASHING THREAD OR RANT THREAD. I'M GENUINELY CURIOUS AS TO THE ENGINEERING CHANGES AND DECISIONS CONCERNING THE REAR AXLE AND TOW RATINGS. NOR DOES THIS HAVE ANYTHING TO DO WITH THE CURRENT RECALL, SO PLEASE DON'T GET THE THREAD SHUT DOWN BY 'VOICING YOUR OPINION' ON THAT SITUATION.

First, I believe @Jowett mentioned in another thread that the gas 3.5TT tundras come from the factory with a ~9.5" rear end, whereas the Hybrid 3.5TT tundras come with a ~10.6" rear end - similar to the 4.0/4.6/4.7 2nd gens coming equipped with a 9.5" rear end and the 5.7 getting the beefier 10.5" rear end. Before Jowetts comments, I was under the impression that the axles were all identical on the 3rd gen (thinking they were ALL the new 10.6 or whatever size it is), but that assumption was incorrect.

Unfortunately, I was quite dismayed to learn this as I was looking at an SR5 (from a distance, anyways) for my next truck. Why an SR5? A couple of reasons - one being cost. Compared to my '13, a similarly equipped '24 would cost almost double. Yikes. I don't mind paying for something I need and will use, but that's a steep price just to get something that I've basically already got, but in a shinier package with fewer miles.

Another driving reason for the SR5 is towing capacity and payload - but this gets a little confusing. The Gen2's had a marked difference between 4.6/5.7 9.5"/10.5" towing capacity. The 10.5 typically came with several thousand pounds more towing capacity. But payload really didn't change much. I seem to recall the 9.5" rearend showing up with a 4050 lb rear axle rating, whereas the 10.5" rearend had a 4150 lb capacity. GVW could be the same (bed and cab configuration changes this a few hundred pounds, but I didn't see more than 100 lbs or so difference between like cab/bed configs).

The 3rd gen seems to be the opposite; the gas 3.5 has more towing capacity and lower GVW with a smaller axle, while the hybrid 3.5 has lower towing capacity and a higher GVW with a larger rear axle. This doesn't make a lot of sense from a buyer's needs perspective or really an engineering capacity (one would think the big axle makes for more towing), but it kind of makes sense from a bean counter's perspective.

With the Gen2, Toyota said the platform has a GVW of 'X' (usually 7200 lbs max); bigger cabs, longer chassis, and bigger motors and axles eat in to that GVW so your payload is affected, but the GCVW remains the same. But the smaller axle rear end limited the GCVW so your towing cap was lower, even if your GVW was near identical. Summary: big axle = more towing capacity. You tracking?

With the Gen3, Toyota appears to have done some payload gymnastics to increase the GVW up to almost 7700lbs for the hybrid, but only 7300 lbs for the gas 3.5. Ok, we saw the 5.7 have a slightly higher GVW in some instances, so that's not off-base. But the towing numbers are... down for the big axle?

And why not keep the GVW the same at 7700 lbs for both drivetrains? That would give the gas 3.5 over 2000lbs payload. I mean, they are basically identical chassis, ya? Frame, brakes, suspension (aside from small coil rate tweaks possibly), body, wheels, lugs, trailer hitch, etc. So why WOULDN'T the gas motor 3.5 have better payload? That's what we see with gas motor 1 ton's vs their diesel brethren from the domestic brands.

Furthermore, why is the towing capacity HIGHER on the SMALLER axle truck? I understand the bean counter explanation: payload is slightly decreased on the hybrids due to the added weight of the hybrid drivetrain, therefore it has a smaller acceptable tongue weight capacity and, in turn, trailer capacity. But big motor, big power, big axle truck should mean big towing numbers.

I thought surely the GVW discrepancy must be due to a lower axle rating on the gas 3.5 trucks. So while I was at the dealership pickup up some oil filters, I perused the parking lot and the 17 new tundras they had on the lot to compare axle weight ratings. I found them to be IDENTICAL in every single cab/bed/motor configuration. Hybrid, non-hybrid, upscale trim, SR5, Capstone, double cab, crewman, short bed, long bed... it didn't matter. Every single truck had a rear axle capacity of 4050 lbs. If they all had the same axle as previously assumed, that would make sense. If the housing, bearings, brakes axle shafts, and everything else are identical with the exception of the ring and pinion, that would also make sense from a payload capacity. But it would stand in opposition to the towing numbers and should, instead, follow the trend of the previous generation with the big tow numbers following the big ring gear.

So I'm confused about the how and why of it. My truck buying philosophy for my use case is simple: big motor, tow package, 4wd, non-steel wheels. That's the meat and potatoes of what I need and everything else is gravy. But with the new truck platform, that option doesn't exist. It's either big motor, small tow package, or small motor, big tow package. I know this has been discussed before, but what am I missing? Seriously.

 

A larger ring gear is generally for handling additional torque. Just cause the ring gear is bigger does not mean the rest of the axle is stronger.

And yes, you’re right, Toyota does a bunch of gymnastics to get payload to be roughly the same across all configurations for some unknown reason.

Also, there is no reason the hybrid should tow more than the non hybrid. Modern half ton trucks are not power limited, especially the twin turbo V6’s. The non hybrid has more than enough power and torque for anything you could put behind it. The hybrid also is not going to be making more power while towing than the non hybrid in general. It’s not like the battery is big enough to sustain 550+ ft-lbs continuously. It would drain the battery for anything beside short spurts here and there.

So the hybrid powertrains additional power and torque can’t really be relied upon or completely utilized during towing and that’s why I have little interest in it. How I use my trucks for towing is 99% freeway/highway driving between 60-70mph and it’s almost worthless there. You are just dragging an extra 500 lbs around with you for minimal benefit. That 500 additional lbs is working against your GCWR, which is probably chassis limited, not powertrain limited.

Also remeber that 4.7 and 4.6L 2G tundras did not just have different axles, but different transmissions and transfer cases too. They have the same a750/A760 transmission that was in the 4Runner and other lighter duty trucks

 

Good points. I have supposed the same about the hybrid towing on extended climbs, but hoped that perhaps getting up to speed would be a noticeable improvement.

I understand that R&P size is generally for additional torque, but going off of the Gen2 R&P towing scheme, it allowed the Toyota engineers to deem it worthy of several thousand addition pounds of towing cap as well. To boot, it appears that the gas 3.5 has approximately the same HP with more torque than the outgoing 5.7L, but with the same axle as the 4.6L and a higher to capacity and GCVW than any Gen2 tundra. Thus, part of my confusion. Perhaps someone is more familiar with the axles specs on either/both the generations and could shed more light on the real differences between all four axles.

To add more confusion to the R&P conundrum, the Gen2 sequoia comes with a 10" ring and pinion, but only holds 2 quarts of fluid and has approximately the same tow capacity as the 4.6L gen2 tundra even though it comes with the 5.7L motor.

 

i was adding to my post when you responded. There is more difference than just the ring and pinion size between a 4.7/4.6 Tundra and a 5.7. The transmissions and transfer cases are different too.

Land Cruisers have the 9.5” axle from the lesser tundras and yet have a 4300 lb rawr

 

True. So I suppose the question needs to asked: why introduce the 10.5" axle if the 9.5" axle would have been sufficient? Again, assuming the gas 3.5 does indeed use a ~9.5" axle.

 

I think what we are seeing is that the Tundra is chassis limited in its ability to handle/stop a trailer. So the GCWR is limited by the chassis and the heavier the truck(IE the hybrid) the lower the tow rating because to are slicing that weight out of the gcwr

 

I was also editing my earlier reply.. haha. Chassis limited could make sense. But why introduce the 10.5" axle for the 5.7 when a smaller axle would have been sufficient as is shown by the gas 3.5's higher torque production and smaller axle?

 

And to bring it back to Gen 3 discussion, why doesn't the hybrid 3.5 stomp the gas 3.5 in towing and hauling? I'm not really trying to ask 'what's the point of the hybrid 3.5' but it starts to look like the next realistic question...

 

Either way, it's still more than the previous Gen, right? My Platinum Hybrid is over 11K and the 2021 max was about 1000 less.

As for why anyone would pick the hybrid, have you driven both yet?

 

I think the hybrid and the gas version have pros and cons with towing. With the hybrid, additional torque is available which will help on hills.

With the gas version, especially in the SR5, the truck is lighter, and therefore there is more payload capacity. With either version, the payload capacity is the main issue that comes up with towing.

 

I checked the Toyota site and used the side-by-side comparison chart. Comparing a gas SR5, a hybrid Limited and the hybrid 1794LE, all 4wd 5.5 bed I'm seeing no big difference in anything but payload. SR5 is able to carry 200 pounds more payload but towing capacities between the 3 is 50 pounds. I've never heard of the 3rd gens having different rear ends between trims, I couldn't find anything doing a quick google search. Also throw in the fact that all trim levels with the exception of the SR can come equipped with the factory rear locker and you're talking about 4 different rear axle configurations.

 

I look at tow vehicles differently. Not overly worried who has more toque, which is lighter for more tow capacity, because in both those cases if your on the edge you need a bigger truck.
I worry with which truck is going to be able to stop my load at 70mph, because once you can’t stop,you never forget that feeling.

 

I've only had the chance to drive the gas 3.5 tundra despite leaving my name at the dealership every couple of months since 2022 to call me when they have one on the lot. Now that they have a glut of them, I got a few phone calls to come trade in my '13 for a newer model but have only taken one test drive while I was waiting for something else at the dealership. I've driven other hybrid Toyotas, but that doesn't really mean much.

That's kinda the point of my confusion. The differences between the pro's kinda don't mean very much. 200 lbs payload, 200 lbs tow capacity, a more robust rear axle on the hybrid. But the con's are a heavier curb weight, more complex system, and a 10k dollar price tag difference... Yet they are the same chassis but the lighter vehicle is derated with the same chassis and the only part I can find that is different being the rear axle...

I occasionally pull grades that several miles long; I don't see the additional torque and HP from the electric motor being available for that length of time if I'm towing heavy or with a giant parachute of an enclosed trailer (or both).

That' is exactly what I though for the last year or two. Jowett is a reliable source with good parts info, so I trust his word on it. Toyota's new parts and TIS system is making that information harder to come by for the new platform so it's been hard to confirm or deny.

Amen to that. Anybody want to talk about GMT400 brakes?? Or 70's 1/2 ton ford brakes?? It would a never ending discussion made up of only three words but with lots of interjected screaming for one's life as folks who have previously owned those vehicles reflexively try to smash their foot through the floor like a Pavlovian response.

 

4Runner towing a 17 travel trailer. We were 65-70% of tow capicity. Came up on a corner and clown is passing on a double solid, I hammer the brakes and we ain’t stopping. Trailer brakes were not locked but close to it left rubber on the road.
Last day we towed with that 4 runner. Went to Chevy 1/2 ton, when we went to a 25’trailer is was Dodge 3500 followed by 2 F350’s.

 

Sounds fun... (that was a lie...)

Brakes were honestly one of the selling points for me when I bought my tundra. I wasn't even interested in a tundra when I was looking for a truck, then after looking at virtually every other truck in town, I crawled underneath one to see the chassis, drivetrain, and the size of the brakes. Coming from tiny single piston brakes on my older truck that started working about 2/3 the way through the stroke, I was sold.

 

The 3rd Gen has new 9.7” and 10.7” differentials. The housing, wheel bearings, and shafts hold the payload up. The housings and shafts are mostly the same between the two out where the most of the weight is distributed. Until we tear into the new axles, we won’t know how they compare to the older 9.5” and 10.5”.

Both the 9.5” and 9.7” diffs are more than likely we’ll up to the task of towing at Toyota’s max rated weight. The 10.5” and 10.7” are gravy IMO… I like gravy.

 

So is it safe to assume that the hybrids came with the 10.7 and the gasser with the 9.7 or did it depend on trim also?

 

Your assumption is correct.

 

I posted this same question several other places, but no one could answer. Specifically it was GVWR ratings. Non hybrids were in the areas of 7200#. The hybrids were 7800#. How's GVWR go up on all trims when they are essentially the same truck.

One guy posted the axles ratings on the hybrid and non hybrid. We chalked it up due to this his how Toyota rated them. Again we concluded Toyota de rates some of the trims for what ever reason. Basically a SR5 gas should have close to 2000# of payload if they kept GVWR at what a hybrid is.