2004 Tundra V8 - Rear differential issue

Hello Friends,

this truck - an SR5 Crew Cab 4 door 4x4, 140k miles - has served us very well in the past 15 years and we need it for one last job, so we need to keep it alive for another year or so. It is developing a whole range of issues, but one that we must attend to is the rear diff. It is leaking oil and making a grinding sound.

We are looking for the simplest and cheapest way to fix it or replace it. The problem is that this version, with the lockable rear diff cost above $800. So here are my questions:

- can we fit a 4x2 diff that is a lot cheaper in it and ignore the differential lock feature?
- is there a repair kit (ring, pinion, gasket, seals?) that is at a reasonable price?
- is there a chance this thing will run another 6-12 months without breaking?

Thank you for your help in advance!

 

Have you verified the oil level is correct? (Take off fill plug and check the oil is up to that hole). Have you used the correct oil for the LSD? You should have a Limited Slip Differential, not a locking differential.

If the oil is correct and filled appropriately, you may have done damage to the ring and pinion, which sounds what you think happened.

Need to check, but I don't believe the axle housings were different between the LSD and non LSD versions, but I could be wrong. If they aren't any different, as long as you get the same gear ratio as the front diff, you'd be fine with a non LSD version.

Where is leak coming from? Pinion seal, axle seals or the differential seal (where the 3rd mates to axle housing)?

 

Thank you for your answer. Yes, there is oil in it, so I think there is some mechanical damage to the diff.

How do I check the gear ratios? Did the different models come with different ratios? Can you maybe link me to the exact item?

 

https://eastcoastgearsupply.com/i-788575-tacoma-8-4-non-eld-t100-tundra-3rd.html

http://home.4x4wire.com/erik/diffs/#T100-Tundra

https://www.lcengineering.com/LCTechPages/TECHGEARJANUARY.html

 

OP doesn't know how to calculate the rear gear ratio, but is certain from his in-depth analysis that he needs and entire rear axle housing and related components because he "hears some noise". Your comments infer that you have little, if any, hands-on practical experience to draw from to do the repairs yourself. You'd probably be best served taking it to a qualified mechanic, spending $100 for them to diagnose and give you an estimate.

 

Scuba's post is great, thank you, I got all the info to figure out what the exact specs of our truck.

We've had the truck inspected by a mechanic and he told us we need to change the rear differential. This is something I can do myself, I have some practical experience. My issue was not wanting to buy the expensive LSD diff and finding the cheapest possible solution.

Thank you for all your answers!

 

Yeah changing the rear diff is actually very easy. You don’t even have to remove the rear tires if you don’t want to.
The axle housing is the same between LSD/ non LSD so you can forgo getting a new LSD diff if you don’t want it.
Good luck with it.

 

I replaced my TRD LSD with an open diff (same problem, leaking rear axle housing, low oil fried the pinion bearing)... Was a direct bolt in replacement.