What Can Cause a Leaking Front Differential?
Front differential leaks tend to originate from one of several different sources, some of which are more concerning in nature than others. By understanding these potential causes, you can get ahead of leaks that appear, before they become extreme in nature. The following are several potential causes of a leaking front differential.
#1 – Differential Housing Seal Leak
The differential housing seal prevents oil from escaping at the mating surfaces between sections. Over time, normal wear and age can cause these seals to leak.
How to Fix: The repair involves splitting the differential to access and replace the housing seals. New silicone seals will need to be installed and proper torque applied on reassembly.
#2 – Leaking Input Shaft Seal
The input shaft seal mounted on the rear of the front differential prevents gear oil from leaking out around the driveshaft connection. If this seal is damaged or worn out, it can leak easily.
How to Fix: Input shaft seal replacement requires the removal of the pre-existing seal, before installing a new seal within the specified bore. Make sure to always use the correct driver for this job.
#3 – Leaking Inner Axle Seals
The axle shafts passing through the differential housing rely on inner seals to contain oil inside. When these seals fail due to general wear, oil can leak through.
How to Fix: The process associated with replacing inner axle seals often varies by vehicle. However, you can expect to remove the old leaky seals, before driving new seals in place with the correct driver, much like is expected during input shaft replacement.
#4 – Outer Axle Seals
Front wheel hub assemblies also use seals to retain gear lubrication around the axle shafts. Failure of these outer seals will result in leaks.
How to Fix: Though technically more of an axle/hub style leak front axle/wheel seal leaks are common, and rather aggravating. Depending upon the vehicle in question, you’ll be required to remove the offending wheel seal or gasket with the appropriate tooling.
After thorough surface prep is complete, a new seal or gasket will be applied and seated as necessary. Reassembly of the problem hub will be the reverse of disassembly.
#5 – Compromised Differential Housing
Though rare, it is possible for a front differential to crack or bust. This is generally the result of undue stress related to impact of one type or another.
How to Fix: Unfortunately, depending upon the exact point of impact, complete differential housing replacement might be required. Repairs of this type can be notably complex and costly. Alternatively, minor damage to such housings can often be repaired by a skilled welder and/or fabricator.
How Much Will It Cost to Repair a Front Diff Leak?
Exact costs associated with repairing a front differential leak often differs from one particular model of vehicle to the next. Nonetheless, there is an average range, in terms of cost, that most repairs of this type fall within.
Generally speaking, you can expect to pay between $250-$500 to reseal a leaking front differential, assuming that no internal differential damage has been incurred.
If major failure necessitates differential replacement, this price jumps considerably, peaking at over $2,000 in most cases. Of course, repair of performance or exotic vehicles will be exceedingly expensive.