I own a Santa Fe with 134,000 KM. Hyundai says I have to replace the differential at a cost of $2500.00

Question edited for clarity and good order.
Question moved to moved to model category.

They tend to hide them under the engine and you access from behind the wheel.

2007 Hyundai Santa Fe Starter

AutoZone.com https://www.autozone.com > hyundai > santa-fe > 2007
PRICE: 215.99 · Mounting Shims Included: No · Tooth Quantity: 9 · Voltage: 12.0 · Family: PMGR (Permanent Magnet Gear Reduction) · Starter Rotation: Clockwise ...

Hyundai Santa Fe Starter Replacement Cost Estimate

RepairPal.com https://repairpal.com > Estimator > Hyundai > Santa Fe
The average cost for a Hyundai Santa Fe Starter Replacement is between $408 and $515. ... Labor costs are estimated between $77 and $97 while parts are priced ...

Get the Best Priced Hyundai Santa Fe Starter

Parts Geek https://www.partsgeek.com > ... > Santa Fe Parts
Replacing a 2009 vehicle starter costs $412 to $514. Repairs at the 2006 Hyundai Santa Fe starter location run from $209 to $276, so model year does have ... ..

Made a video showing how to replace the radiator on my 2005 Hyundai Santa Fe and in the process I show where the drain plug is.

Made a video showing how I replaced the radiator on my 2005 Hyundai Santa Fe and in the process I show where the drain plug is.

It really depends on where the leak is, if it is cooler lines it could get spendy, rear seal not so bad, pan gasket, not so bad, if you could let me know where it is leaking i could get you a better idea of cost.

It's do-it-yourself. Differential fluid is only filled to about half the ball. When you take the screw off, you won't loose much fluid since to check the level of fluid, you can just stick your finger in to check the level necessary. If it is in fact that it's leaking from the differential, just buy a replacement or required gasket and screw it back in. That should solve your problem.

normal recommended practice is 100,000 km but can last up to 127k-160 but would not leave it for that long as a broken belt will cost more than to replace one before time.

Some vehicles had filters and some didn't. If you have a filter it will be inside the transmission pan, and in that case there won't be a drain plug. You just take the pan off and try to get as little on you as possible when all the fluid comes out. MUCH easier if you have a lift.

If you don't have a pan then the drain plug is on the bottom. Manual transmissions don't have a pan, but sometimes the automatics didn't either.

Fluid: Hyundai Manual Transmission fluid if it's a 5 speed, and Hyundai ATF or Mitsubishi Triple Diamond ATF only if it's an automatic. Dexron and generic ATF does not fair well in these transmissions.

Call a dealership parts department with the VIN number and see if there is a filter kit available for your vehicle if it has an automatic transmission.

First things first. My experience tells me you need to test a few things first before you spend a lot of money. Find an OBDII scanner & check for any powertrain trouble codes (DTC's). If any, investigate & repair as needed.
1. Check fluid level & condition of trans - should be at the 'full' mark and relatively clean. If low or dirty, replace & adjust level. Use ONLY Hyundai SPIII fluid.
2. Check/test the throttle position sensor (potentiometer) for any bad spots (use an analog ohm meter).. if you don't know how to do it, find someone who does. Replace as needed.
3. ZERO out the TCM (PCM). This clears all adaptive values in the computer (this computer is a learning computer and accumulates driver's driving habits). This can be done by disconnectiong both battery cables and touching them together for 30 seconds. Then reconnect them to the battery.
4. Now, if your Santa Fe has the 3.5 lit V6, then your engine is equipped with the ETS (Electronic Throttle System) which incorporates another sensor called the APS - Accelerator Position Sensor - check this one as well (also a potentiometer). replace as needed.

Use ONLY Hyundai SPIII fluid - no other substitute is available. Several ways to do this - drain & refill several times: run engine to operating temp and cycle the trans through D & R. drain fluid again, refill and run engine again and cycle D & R, drain and refill again. Do not over fill - check when fluid is hot, the adjust level.
The other way is a Trans-Flush machine which performs a 'fluid exchange' - pulls old fluid out while replacing it with fresh fluid while the engine is running at idle in Neutral.

did you mechanic change the timming belt that happens and also if it is slamed in to reverse while driving will damage it that way also