Modular torque converter question

[mercurygm88]

Hey all, I came across a new one today that I'd never heard before and thought I'd run it by you guys and see if anyone has ever heard this. My dad has a buddy who is a mechanic, used to be a Ford service manager and now has his own shop. The guy is very good and he's normally the first person I go to for advice and he's never led me astray. But tonight he told me one that I think is a whopper he pulled out of his ass, so here it is. He says it's a very well known very common problem that the torque converters Ford used in all modular applications swell over time generally worst between 100,000-150,000 miles. This swelling puts pressure on the rear main seal causing it to leak, this all came about cuz dads 2002 E150 with the 4.6 is at 165,000 and has a slow rear main leak. Dad's buddy says it's hard to find a 4.6 with over 100,000 miles on it that doesn't have this rear main seal leak from the torque converter swelling. In all my ten years of experience with four 4.6's I've personally owned and many more I've helped friends and relatives with this is the first rear main seal leak I've come across.

So what do you all think is this really a well known issue with the modular motors that I've somehow just never heard of? or is this guy making up B.S.?

[gadget73]

I've heard of converters swelling in performance applications but don't know how common it is. not hard to check though. Unbolt the torque converter and see if it will slide back. If it does, its not pushing on the crankshaft. I also don't see how it would push on the seal. If anything is going to happen, the crank is going to be pushed forward, not the seal.

[VicCrownVic]

I've heard of the the stock non-P71 torque converters swelling/ballooning when ran with a P71 ECM such as an ARA3. I haven't heard of the rear main seal, but my experience is quite limited so I really can't say that it's not a common problem.

[sly]

From what I know, ARA3 (1999 CVPI) pushes a lot of pressure and without a jmod, there's not quite enough flow in the TC passages of the valve body for pressure relief at high RPM.That year CVPI was also known for ballooning the TC. It generally comes from higher RPM usage. Towing, racing, pursuit, etc. I do think vehicles with the 4R75 instead of the 4R70 are less prone to it, but I could be mistaken. I've never heard of that happening with the 4R100 in trucks though. I wouldn't say it's a common issue, but I would say it's a known issue.