We warranty the transmission as to the most likely cause of failure for these transmissions: the clutch “A” drum rim being damaged due to an overpressure incident due to a pressure spike that slips past a worn-out pressure regulator.

You would already know that the clutch “A” drum on the transmission you’re buying from us is structurally healthy otherwise the transmission would not have functioned in 1st, 2nd, 3rd and 4th — only 5th (as to the forward gears).

The whole point of us installing a renewed pressure regulator is to protect the “A” clutch drum, so that’s what we guarantee. If, within 3 years, you experience the classic “A” clutch drum failure symptoms (slipping in 1st, 2nd, 3rd and 4th but not 5th), then you get to make a warranty claim.

Our warranty claim works like this: the price of the transmission is $1,800 and our warranty covers 3 years, i.e., 36 months, so that works out to $50 per month. So for every month that this specific failure occurs short of the three-year mark, you get a refund check.

So, while our warranty covers what we understand to be the most likely cause of failure, it doesn’t cover a great many other ways in which your transmission might fail — less likely yet certainly possible. For example the more likely candidates are:

• The sprag clutch might fail
• The “F” clutch might fail
• The torque converter clutch might fail

The easiest fix for this is to install a rebuilt-by-ZF (or a ZF distributor) torque converter when you install the transmission.  We can point you to an official resource as such.  The last such unit we bought from him was priced at $300.

Then again, anything in this, or any, transmission might fail, but the above are generally considered the most likely issues.

In addition to that, your mechanic might not flush or decontaminate the transmission cooler lines before installing the transmission. You might other parts of the transmission with peculiar driving such as putting it into park before the vehicle is at a standstill, or putting it into “D” while it’s rolling backward, or into “R” while it’s rolling forward.  None of this should damage the “A” clutch drum though, which is why we’re willing to warranty that specific part — and only that part.