# Transfer Case Service in Upland > 4WD or AWD acting up? Route 66 Auto Repair in Upland inspects the whole transfer case, from fluid to shift motor, and tells you what needs work now. Source: https://route66autorepairshop.com/transmission-services/transfer-case-service Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** The transfer case is a **whole system**: fluid, chain, bearings and shift controls. We test it end to end and **label each finding** now or later. The transfer case splits engine power between the front and rear axles on 4WD and many AWD vehicles, and Route 66 Auto Repair in Upland services and repairs it. This page is the system view: fluid, seals, chain, bearings, the shift motor and the controls. If your truck will not shift into 4WD, makes noise, or leaks near the middle, our ASE-certified technicians sort out which part is at fault before quoting. ## What are signs of a transfer case problem? - 4WD will not engage, or the indicator light blinks - Grinding or clunking when shifting between 2WD and 4WD - A whine or growl that changes with speed, not engine revs - Binding or hopping on tight turns in 4WD on dry pavement - Fluid dripping from the middle of the truck - A service 4WD or AWD warning on the dash ## How do we check the whole transfer case? We start with a scan, because many modern transfer cases shift with an electric motor and a control module. Codes point to the motor, an encoder or a wiring fault. Then we check fluid level and condition, which tells a lot about the chain and bearings inside. Metal flakes or a burnt smell move the internal parts up the list. Next we test engagement on the lift and on a short drive, listening for noise in each range. From there the job may be a simple [transfer case fluid change](https://route66autorepairshop.com/transmission-services/transfer-case-fluid-change), a [chain replacement](https://route66autorepairshop.com/transmission-services/transfer-case-chain-replacement) or a [bearing replacement](https://route66autorepairshop.com/transmission-services/transfer-case-bearing-replacement). A standalone [transfer case inspection](https://route66autorepairshop.com/diagnostics-and-inspections/transfer-case-inspection) is available if you only want the findings. ## Our transfer case service process 1. **Scan the controls:** We read 4WD and AWD codes and check shift motor operation. 2. **Check the fluid:** Level, color, smell and any metal on the drain plug magnet are recorded. 3. **Test every range:** Engagement is tested in 2WD, 4-high and 4-low where equipped. 4. **Estimate by finding:** Each problem gets its own line and a need-now or need-later label. ## What's included in a transfer case service visit - 4WD and AWD system scan - Fluid level and condition check - Seal and vent inspection - Shift motor and range engagement test - Driveshaft and yoke play check - Road test with noise notes - Written findings with photos where useful ## Which transfer case problems can wait? **Need now:** - No engagement when you rely on 4WD for work or weather - Loud grinding or binding - Fluid leaking fast enough to drop the level **Need later:** - Fluid due by mileage on a quiet unit - A light seep at a seal - An intermittent indicator light with normal engagement ## How transfer case work is priced A fluid service is short. Electrical faults vary with where the problem is. Internal chain or bearing work means removing the transfer case, and that removal time drives the cost. Your written estimate shows every step and every part. The diagnostic fee is stated at the counter and applies to approved related repair. AAA members save 10% on parts and labor, up to $75. ## After transfer case service Engage 4WD for a few minutes once a month, even in the dry, on a straight road at low speed. That keeps the shift parts moving and the internal parts coated. Declined items stay on your repair order so you can schedule them later. ## Frequently asked questions ### Do AWD vehicles have a transfer case? Many do, often a smaller unit sometimes called a power transfer unit. Some AWD designs use a different layout. We look up your vehicle and tell you what it has. ### Why will my truck not shift into 4WD? Common causes are a failed shift motor, a wiring or switch problem, a stuck shift fork, or a front axle that is not engaging. A scan and a test drive narrow it down. ### Can transfer case problems damage my tires? Yes. Driving in 4WD on dry pavement, or running mismatched tire sizes, makes the drivetrain bind and wear. Keep tires matched and rotated; see our [tire services](https://route66autorepairshop.com/tire-services). --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.