Overview
The TeraFlex 3440000 is an upper and lower ball joint kit for Jeep Wrangler JK Dana 30 and Dana 44 front axles. It is the non-knurled version, made for knuckles with a tight bore. It is a direct replacement for 2007–2011 and most 2012 Wrangler JK models.
The upper joint uses hard sintered wear bushings to handle heavy side loads from larger tires and offset wheels. The lower joint has a threaded top cap for adjustable preload and a machined grease passage, so it can be greased without removing the axle shaft, even with the larger RCV shafts. The adjustable end cap gives lateral greasing access, and the boot is locked in place with a spring and a spring steel ring. The upper joint has a magnesium phosphate coating and a factory-style serrated flange nut with a grease fitting.
Key features
- Sintered wear bushing in the upper joint
- Threaded top cap on the lower joint for preload adjustment
- Grease passage through the lower housing
- 4140 chrome moly ball and stud with magnesium phosphate coating
- Factory-style serrated flanged castle nut and black neoprene boot
Greasing and tight bores
Ball joints carry steering and suspension load at the knuckle, so their condition affects steering feel and tire wear. A worn joint often shows as play when the wheel is lifted and rocked, or as a torn boot that has let grease out. Dry joints wear faster, so regular greasing is part of keeping them in service.
When installing a non-knurled joint, the bore should be clean and sized for a tight press fit. Check the knuckle for scoring before pressing in a new joint, and confirm the joint seats square. Ball joints are often replaced in pairs, and a front alignment check afterward helps protect new tires. Greasing the lower joint through its passage is simpler when the axle shaft stays in place.
- Clean the bore before pressing in the joint
- Check boots for tears at every service
- Get a front alignment check after replacement
Specifications
| Brand | TeraFlex |
|---|---|
| Part number | 3440000 |
| UPC | 843885031239 |
| Joint type | Upper and lower kit |
| Knurl | Without knurl |
| Upper bushing | Sintered |
| Ball and stud | 4140 chrome moly |
| Housing | 1045 carbon steel |
| Lubrication | Grease fitting, lubeable |
Vehicle fitment
It fits 2007–2015 Jeep Wrangler (JK) models, including Rubicon, Sahara and Unlimited versions. As a direct replacement it suits 2007–2011 and most 2012 models, and late 2012 and newer models need modification. Make sure your year, model and trim are covered before you order.
Earlier and later Wrangler generations are outside the listed years. Confirm your vehicle’s year, model and trim before ordering.
Installation notes
Some 2012 and all 2013-and-newer JK models have larger front axle shafts. Those models need grinding on the stub shaft forging parting line for clearance before installation.
What’s included
One upper and one lower ball joint, without knurl, with the lower joint’s castle nut and boot.
