Vannin' Home Forums Astro/Safari General Discussion i have a whirring noise, maybe someone has an idea

Might not be a bad idea to get the driveshaft ballance checked too. . .

Shifting problems and a whine under acceleration leads me to believe it is rear axle gears (hopefully) or, more likely, transmission gears (more expensive and involved than rear axle gears).

I was thinking about that. Will see how much the U-joints help since it is an easy job to do, and then I'll look at the drive shaft.

The tranny should be fine and isn't clunking at all. In fact upper shifts are super smooth. Just going from 1st to 2nd is noticeable, but not clunky at all. If I do have to take a look at the diff I'll be taking it in to get it diagnosed.

One bit of good news, that Ford 9" you have under there, from your other post, is a EASY repair / replace !

1) pull the drums off
2) behind the axle flange , where the wheel studs are, you will find four bolts, remove them
3) pull the axles out about 2-3 inches
4) remove the bolts around the center drop out
5) go to bone yard, find a 80-90 Ford van, take the center drop out from it the same way
6) reverse process putting "new" drop out in the Astro

That is a very simplified step by step, but come close to the rear thing. Best of luck and keep us posted.

Yeah, so glad its the Ford. I was worried there for a bit. Doing the u- joint Saturday, then if it's still loud will do a swap. How hard is it to go from 4.11 gearing to 3.73?

Changing the gears with a Ford 9" is easy, just find a drop out in the bone yard with the gears you want. I would not recomend a gear set taller ( lower number ) than a 3.73:1 with the OD trans as you risc putting the motor into too low a RPM range on the highway and loosing mpg. Stick with 4.11:1 for better power or 3.73:1 for better mpg on the highway .

Most full size vans with a 9" will have 3.73 gears.

I've heard 3.73 gears are best of both world's. I do like the power with the 4.11's though.

I finally broke down and took it in and the pinion bearing was bad. Got a new rear end with better gearing to hopefully help with MPG's while still being quick. Took them a while to get it right but it's nice and quiet now. Next is the electric gremlins to figure out.