Transmission noise

[Kandrae]

Looking at buying a 1999 e 250 4x4 with the 7.3 only 39000 miles.
When test driving it at 40-45mph and then gettig on it pretty heavy it will down shift, then when it shifts up again it makes a wummmmb (going over a cattle gaurd at 60mph) sound. This happens at exactly 49 -50 mph, the sound that is. Torque converter replaced 600 miles ago, fluid is fresh clear pink.
any ideas of what this is , and should it be of great concern?

[MadScience]

Why was the torque converter replaced at less than 39k?

That's hardly typical, and without knowing how it failed, you can't be sure that it didn't send shrapnel through the rest of the transmission.

The fluid would have been drained as part of the replacement, so you're looking at fluid with 600 miles on it. It won't tell you anything useful.

I'd probably negotiate a price that works even if the transmission needs to be rebuilt. You could also try talking it over with a specialist (there are folks that do little but work on the c6, e40d, 4r100. they may have some ideas).

[twogone]

My '95 7.3 EB does exactly the same thing. At first I thought it was a tranny slipping problem, however, I never felt an actual slip. After more than 10K miles on 33's I've actually quit noticing it. Mechanic says it is a "characteristic". BTW, in my past experience, ANY tranny shrapnel = walking.

[BajaSportsmobile]

Originally Posted by Kandrae

any ideas of what this is?

Something besides the transmission - U-joints, motor mounts, drive shaft slip yoke...

[twogone]

... and, is the van on tires larger than 245's? Bigger tire changes the "feel" due to gearing/low rpm.