By January 29, 2013 0 Comments Read More →

Rear Main Seal Leaking

Reader Question

I had my transmission replaced about a month ago and now man van is leaking oil from the rear main shaft.Could the rear oil leak be because of the transmission repair.

Thanks for your time


Hi there,

Yes, it can be caused by recent transmission removal. The rear main seal is a fairly large and somewhat hard plastic oil seal that is located between the engine and transmission.

When you remove the transmission you take a huge risk of moving or damaging the rear main seal.

Anytime I remove the transmission I replace the rear main seal just for my own personal insurance against these types of issues.  I don’t want a mad customer or to have to do the job over again.

Now, can you get your transmission guy to install a new seal at no charge?  Probably not.  They SHOULD be willing to do some of the labor again at a cost basis or some large discount, just have to ask them.

Using thicker engine oil weight, such as Castrol 20w-50 can help to slow down the oil leak, unless it is visibly dripping. There are oil additives that are made for rear main seal leaks as well, although honestly I have never had any luck using them.

Austin Davis

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Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."