How to upgrade your 3rd Gen Gas tank to 33 gallons!

Ok so I finally swapped out the tank.
And while I fucked mine up more than I'd like to talk about. I learned some things to make it easier for the next guy.
Currently my truck is at a Toyota dealership getting unfucked (and some maintenance too why not).
Got my truck back and made some observations. See bottom for edit.


Also it is currently not known to be possible to reset the computer to read the tank correctly. Your DTE may forever be wrong. (Worth it in my opinion.) I talked to the master tech and he tried at my dealer and was unsuccessful.

BUT if you follow my do's and don't you'll be fine.
First lets look at a 22 vs a 33.
It's a damn behemoth. Be sure to have a nice floor jack (ideally 2) and a friend.

Next we'll look at what parts you need to order. (here is where I first fucked up)



Looking at this parts diagram it's hard to tell but there's 3 parts you need to order.

77601E - Front strap.
77644 - Bolt for front strap.
77611E - Pin for front strap. (I'm unsure if this includes the cotter pin. Any cotter pin should work if it doesn't)

I fucked up and thought the front and middle strap were the same. They are not. The front's smaller and holds the front up higher in the frame for the gas, at level, will naturally flow back to the pump. You absolutely can use the middle strap from your 22 gallon on the front. It will hold it. But it won't hold it right. I drove to and from work for a couple days like that with no problems. But I wasn't getting all 33 gallons as it was pooling in the front due to sag.

Speaking of sag. Someone else on the forum did this mod as well and he said it was fine running without a middle strap. DO NOT DO THIS. 33 gallons of gas is heavy. 201Lbs (if 6.1Lbs per gallon). I noticed the middle of my tank sagging and warping my tank after just 3 days. So not only was it pooling in the front but now it's pooling in the middle.

Order the parts. Don't risk it on your expensive truck. I fucked up so you don't have to.

Now lets pull the old tank.

STEP ZERO

!!!!! DISCONNECT YOUR FUCKING BATTERY !!!!!!

10mm socket to pull negative terminal

I will not be responsible if you turn your Tundra into a fireball. Actually I'm not responsible at all. You're all adults here. You understand you're doing this at your own risk.

Tools:
14mm socket
12mm socket
Pliers for pins
Flathead Screwdriver for clips
Floor Jack x2 (ideally. You can do it with one but it's harder) (Another mistake I made)
Jack Stands and Wood blocks (Blocks are optional but the tank is plastic)
Gas tanks with your gas of choice. I recommend 10 gallons as the 33 has something like an 8 gallon reserve to it.

You do not need to jack up your truck to do this either. You're welcome to but be careful as you might fuck up the wires for the pump and gauge (foreshadowing!!) when dropping out the old tank.

1. You're going to want to run the tank as empty as possible.
2. Place the jack on the front of the tank and support it's weight.
2a. (I forgot this part.) Remove the little triangle shaped support near the front 2x12mm bolts.
3. Undo the front strap by unbolting the 14mm bolt on the outside right on under the frame.
4. The strap should fall off and dangle. (Tank supported by the jack)
-Which should be light if you followed step 1. >.>
5. There's a Pin holding in the other side of the strap. Pull the cotter pin out of it then slide it out and then the strap is free.
6. Lower the tank until you can get your hand and ideally a flat head between the tank and the bottom of the bed.
7. With the tank slightly lower, fold over the heat shield until you can see the tube with a blue clip. This is your pressurized fuel line. When disconnecting this it will spray you with gasoline. Don't be smoking at this time.
- That tube is connected to a line that is pinned to the frame so we need to disconnect this to avoid screwing it up.

STEP 7 PICS

8. Once that's disconnected. Place a jack stand and a wood block under the front of the tank so you can remove the jack. (Not necessary if you have 2 jacks.)
9. Move to the rear.
10. Support the rear of the tank with the jack so it won't just drop.
11. The Strap comes off the same way but this strap is just bigger and has a drop that it bolts to.
12. Once the strap is removed lower the tank exactly enough that you can get your hand in there and disconnect the 2 plugs. One is for your pump the other is for the gauge. You gotta squeeze these things hard to get them off. You do NOT have a lot of room for the tank to drop with these plugged in. I almost broke one of my wires doing this as I came too low. I'm still not sure if it'll last. You can see the plugs if you look between the tank and the frame rail.

STEP 12 PICS


13. Once those plugs are out you can lower the tank a little more so you can un-clip 2 (what I assume is) return tubes. There's are large and have quite a bit of slack. Not too hard. For the purple one I again folded down the heat shield a little bit to get to it.



14. lastly undo the filler neck it's held on with a grey clip. You'll just have to wrestle that bugger off then wiggle the tube. It'll eventually get free.
15. Once you're sure you've undone all 6 connectors. (Blue, Purple, Red, Grey, Wire Plug1, and Wire Plug 2) You can lower your jacks and pull the old tank out.


Now the tricky part is getting the new one in.

For the most part you'll just do this guide backwards. I'm not gonna rewrite the whole thing but I will leave some nuggets of wisdom I learned the hard way.

Again order the parts. Don't cheap out here.

These aren't really steps just loose observations in an order.

The new tank should also be empty. Otherwise it'll be a nightmare to work with.

1. Go under the truck with no tank and look at the frame rails. Pay close attention to them in relation to the divots on the top of your new/old tank. (Mistake I made and warped my tank)
2. Slide your new tank in. Careful not to scratch it up too bad on the cement.
3. Raise it up and reconnect all your connectors. Be sure they're good and snug and won't come out. When dealing with turbos the fuel pressure is higher than a non-turbo vehicle. You don't want these popping off.
4. Lift it into place lining up the frame rails. You do not have much clearance here and you'll already be "squishing" the tank against the bottom of the bed.
5. I recommend starting with the middle strap as it's hardest to get in. This will be labeled "2" on the strap.
6. Try not to let the tank rotate on the straps. It'll naturally try to and it's annoying as hell.
7. Snug up all the bolts and be 100% sure you have. The tank should sit in the straps flush if not you did something wrong (and maybe warped your new tank... ask me how I know)
8. Go slow.
8a.(Forgot the triangle thing again.) This goes up in the slot near the front of the tank.Theres a divot for it. Hard to miss.
9. Once it's all bolted up and snug lets plug the battery back in.
10. Use some gas tanks to put some gas in it.
10. The dash will read 0 gas. It'll say this no matter how much you put in it. It won't read full until you go fill it up. (unless you fill it up from the start. At which point if you have a drum of gas laying around why did you get a truck with a 22 gallon tank?)
11. You should be good.

I didn't get to empty mine even once before the sagging made me nervous and bitch out to a Toyota dealer. If you followed this you shouldn't need a Toyota dealer though.

It ran fine. I put about 100 miles on it before the sagging started to make me nervous. It's also really hot where I live and the truck is solid black so I think that played a large role in my sag.

If you have any questions or wanna discuss feel free. If I left anything out I'm sure someone will correct me.


Edit: I have got my truck back a couple days ago. The tank was at the same level when I dropped it off. So either they drained it and refilled it or never drained it. According to the tech's I did a decent job just didn't quite line it up into place and used the wrong straps in the wrong place. The front strap has a 1 on it. Middle 2. Rear 3. So far the needle is ready right and the DTE is still assuming 22 gallon. BUT It's stopped counting down as fast once I got below half a tank. Will update once I've gone through a few tanks and have more info.

 

Outstanding write up! Props to you!

 

Thanks. Lessons learned with sweat and cussing a lot.

 

Great job on this! Love that folks are starting to really dive into the third-gens.

 

You are a GOAT with that comment lol

 

Awesome write-up! This is the last mod that I would like to do on my truck (eventually, tires will be next).

 

GOAT thank you so much!

 

Excellent write-up. Love the detail and appreciate the tool listings. Just curious, why would somebody go through the hassle and expense for this mod? Traveling long distances off-road?

 

For me I grew accustomed to my RAV4 hybrids range. Filling up then having 500 miles was nice. When towing something your MPG will drop to like 13. With a 22 gallon and a 4 gallon reserve you get 200 miles of range and off-roading you're looking at even less than that. If you're doing any overlanding some trails can be that long.

As for expense, had I ordered the right parts from the get go I would've been out about $700 total. $700 to add 50% range isn't a bad trade off. Also I paid 36k for my SR5 with 4x4. So all and all I'm still under 40k and the small gas tank was my only complaint about the trim I got.

To each their own. If you get a slightly higher trim than me you get the better tank anyway. But the next cheapest Tundra with 4x4 in my area was pushing 42-45k before TTL. I definitely would not get the tank at MRSP, it's like $1300 without the pump or any of that. I got a used one out of a totaled platinum for $600.

 

Towing range and range in general. I get it. Thanks so much. And parting it out via salvage makes the story even better. In ski country, we have a saying, "If you're going to be stupid, you better be tough." For this thread, I would change that to, "If you're going to be awesome, you better be stubborn." Congrats.

 

I made some edits to the post since I have my truck back now.

 

Does this fit the 3rd gen Sequoia as well?

 

I'm not sure. I haven't even seen one of those in person yet.

 

Any update on this , has the DTE adjusted?

 

Ah yes I forgot to come back.

(or I avoided this site because being told 5 times a day every day that my truck will explode got old)

No after several tanks and a 26 hour road-trip it never updated.
I looked into it and researched.

It appears the data is stored in the gauge cluster. I thought it was in the ECM so I actually disconnected my ECM and put in a junkyard one and it still showed all my DTE and mileage. So it never reset. (Also wouldn't start lol)
Ended up returning that ECM anyway since you can't start the truck with an ECM that wasn't programmed for yours originally. Also I was informed by 2 dealers that once an ECM is programmed it CANNOT be reprogrammed for a different truck so you HAVE to buy a new one if you want a new one.

I haven't wanted to take apart the dash to swap out the gauge cluster enough to try it yet.

But I'm fairly confident after all my testing that a gauge cluster from a 33 gallon truck will probably fix it assuming it's not programmed to only work with 1 truck. Idk if it'll mess up your odometer either.

I will say I'm still pleased with the mod despite these things. I just remember to reset my A counter every time I fill up. Even if it was correct to the truck or I bought the 33 galloner to begin with it's not accurate DTE. There's a 10 gallon "reserve". So I just multiply my average MPG (something I reset at every fill-up also) by 30. And I make sure to not surpass that with what my ODO says. Usually about 510 Miles and that still gives me a 3 gallon reserve in case my math is wrong and for other variables.

I've put 100 miles on it while it said "Refuel now"...

Anyway DTE will not update that's hard coded in the truck somewhere. I asked the dealer about it and he said you'd have to swap the ECU, ECM, head unit, and gauge cluster to make it right. Fuck all that.