2005 2WD differential replacement

Hello All. My Tundra finally has a problem I need help with. There is a knocking noise when I accelerate. I finally got under the truck and found the noise to be coming from the rear differential. I'd like to replace it with a used one. How do I find out what ratio it is? Can I replace a 4:30 to 1 with a 3:90 to 1? Any recommended parts places for a used diff?

 

You can have it rebuilt for around $1200 if you pull it and take it to a shop that is known for diffs. You can put whatever gears you like in there. You can also have one mailed to you from East Coast gear or something. Or find a used one perhaps. If you’re ever gonna put larger tires on there 4.56 for 32-33” 4.88 for 33-34 would be my recommendation.

 

Thanks for that. Then you know what you're getting. I'd like to get a little better mileage with a 3:90.

 

You are aware of the major known issue and TSB with the transmission crossmember coming unbolted on 2WD which has the exact symptoms you describe, right?

 

I guess I could've linked it.

Details about what comes loose can be found here, it's the 4 center bolts hidden up/under the middle of the transmission crossmember. See the missing bolt to the left of the white centering nub in this picture - this member was missing 3 of 4 bolts from the factory, and the one remaining bolt was loose so their transmission was just slapping around when they accelerated and hit bumps.

The TSB itself can be found here with the details you need, but you won't need to replace it necessarily. Tighten the bolts using blue Loctite, replacing any missing.

I also recommend you read this thread.

If you don't find any bolts missing, tell us some more details about what you're experiencing. At least you'll get a sanity check about whether it's actually the rear end.

 

Check this, it happened to mine.

 

I’ll have a look. Love these forums. I had the vehicle up on stands and ran the engine until the noise was there. Fairly certain it came from the diff.

 

You could be right, but enough folks on here have gotten bitten in the ass on the crossmember thing ... it's worth checking out.

I mean, if you're lifted, and you have larger tires, it could be worthwhile doing the upgrade to 4.3 if you can find something that'll work. Or even 4.1, but ... yeah.

 

I’ll definitely have a look. I thought I had it when I replaced the bad center support bearing and the rear u joint.

 

You have factory 4.30? Is that on a v6?

 

Dont expect much extra economy from a gear swap. The truck is still pushing the same amount of wind, and dragging the same weight, and at any given time is going to need the same amount of hp (fuel) regardless at what rpm it does it. The v6 has a higher rpm torque peak, so it'll be a little happier at a little higher rpm anyway. Just stay out of OD under 50.

 

My Tundra is the V8. Not sure what the current ratio is. Just checked all the cross member bolts and they are secure. There are not any metal shavings in the gear fluid I drained out.

 

If we are to believe the brochures, it's either 3.91 or 3.92 if original.
That's determined by cab type, which with a V8, you have either RC, AC or DC....which is a good item to add to your profile or a post you make. Adding trim type....Base, SR5, Limited would be a bonus.

1st Gen Tundra Brochures, Owner's Manual and Maintenance Schedules | Toyota Tundra Forum (tundras.com)

 

Hell yeah, my truck has the best turning radius out of all of them.

 

V8 is probably 3.90

 

Project is done. I purchased a used diff from eBay. That works fine. While I had it apart I did the wheel bearings and axle seals. Finished it off with the drum brake overhaul. Next is adding transmission fluid.

 

Where did you get the drums from?

 

Amazon. I got the drums, pads and hardwear together.

$126 Detroit Axle - Rear Brake Drums for 6-Lug 2003-2006 Toyota Tundra, 1999-2004 Tacoma, 2002 4Runner Brake Drums 2000 2001 2005 Replacement Brakes

https://www.amazon.com/dp/B07DGJXJ9Y?ref=ppx_yo2ov_dt_b_product_details

 

If you notice any weirdness with your braking, note that an exorbitant amount of folks have come here after replacing with store-brand drums, bought either from brick-and-mortar or from scAmazon, and reported vibrations, chunky braking etc. because the drums were out-of-round. Aside from the fact scAmazon is a huge source of very authentic-looking counterfeit parts, so we must assume what you got was actually legit, if you notice weird stuff, pop off a drum and take it to a shop to ensure it's in-round. Else have them turned. You may not notice right away.

Avoid buying parts on scAmazon, fleaBay, WallyWorld online. Several folks (including me) have received a variety of white-box generic and full-on bogus parts from here. Spark plugs are a huge one. And there is NO protection, it doesn't matter which "Storefront" you buy from, if scAmazon if fulfilling the purchase, the item is typically coming from shared inventory bins at your nearest shipping warehouse, and the inventory hitting those bins isn't adequately scrutinized.

Used parts on fleaBay is another beast. It's the new stuff you need to worry about. Other vendors like RockAuto and Summit will get you guaranteed authentic parts at competitive or better pricing.

 

Probably all true. So far so good. I'll keep you updated.

 

Here is the damage to the old diff. Hate to admit it but I ran the fluid low.