A question of trust

I’m in the market for a used minivan and had found a great deal on a Sienna from a local dealer.

Before I bought it I had my (trusted?) mechanic give the car a once over to make sure nothing was wrong with it.

He drove it around the block before he took it into the shop and then came back to get me because he said he wanted to show me something.

We took the van back out and from a stop, slowly got the van up to 1000rpm, then floored it and we watched the tach go up to 3k or 4k rpms for a brief second before it went back to 2k rpms and we started accelerating.

He said that this was a sign that the transmission was starting to go and he also showed me how the trans. fluid looked new because they’d probably changed it in an effort to fix the problem.

My mechanic also has a small dealership of his own and was a little disappointed that I didn’t buy a van from him, so my question is did he make this up? Is it something that all cars do when they’re floored like that or did he help us dodge a bullet?

How old is the van? The reason I ask is Siennas had transmission problems up until about 2002, and repairs were covered under a secret warranty.

However, based on your description, it seems the transmission might be slipping a bit, but really, I think it’s perfectly fine and normal. You could always go to your local Toyota dealer and take a Sienna for a test drive, and see if it does the same thing.

Did the transmission downshift when he floored it? If it did (as it should), then of course the RPMs will jump quite a bit until it upshifts again. Try this test for yourself:

Assuming that your present vehicle has a tachometer, try to duplicate the situation that you experienced in that Sienna. Take it slowly up to 1000 RPMs (which a very slow engine speed, and while you didn’t tell us how fast he was driving, I am going to assume that he was driving the Sienna at around 25 mph) Now floor it, and see what your tachometer registers. I am willing to bet that you see a reading of at least 3k on your tachometer, just like you saw on the Sienna’s tach.

That being said, even if you can duplicate the situation on your present car, that doesn’t mean that the Sienna’s transmission isn’t slipping. If you are really interested in this van, you might want to take it to another mechanic and, in addition to asking for a general pre-purchase inspection, you should ask specifically if it appears that the transmission is slipping. If the Sienna gets a clean bill of health, then that tells you that your “trusted” mechanic is actually a sleaze-ball.

It’s unclear from your post if the transmission is revving higher due to hard acceleration before going into the next gear or if this is a shifting flare. The latter is not good.

You can perform a converter stall test if you care to. It’s done like this.
Set the park brake, hold the foot brake, shift into LOW and rev the engine quickly. The engine should stall out at around 2000 RPMs and not rev any higher.
Allow the engine to idle for a couple of minutes and repeat this in 2nd gear.
Repeat process in DRIVE. The results should be the same and you MUST allow the engine to idle for a few minutes between each test.
Perform this test only once if you do it.

If the engine revs beyond 2000 RPM on any of them then the transmission has internal problems.
Offhand, I’m giving your guy the benefit of the doubt. A potential shifting oddity and new fluid does look suspect.

Thank you folks for your quick replies.

The minivan is a 2004 Sienna and the price was 13k. Does that sound too good to be true? They’ve had the van for about 9 months and had to lower the price by 3k over that time. I just can’t believe that others didn’t buy this van because they were able to pick up on what seemed to me to be such a subtle hiccup in the tranny.