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Sat Nov 23, 2024 10:43 am

Hello I have an air cooled four-speed with a new rack and pinion that has about 15,000 miles on it now.
I’m rebuilding the engine so since it’s off I’ve decided to freshen up the gearbox with some new seals . it was leaking from the drive flange seals.
I checked the backlash and it was at 10 thou. Wear pattern looks good. My question is whether I should tighten up that backlash back to 6 thou or leave it as is.
I also have a question about setting the preload. I have read that the spinning torque method is problematic, and that the way to go is by finding zero preload and then tightening the adjuster ring 1 to 1.25 inches. Does this mean tightening just one adjuster 1” or both 1”? Also this is for new bearing I assume. My bearings look great so I’m going to reuse them. Since they have already worn in should I put less preload on them? Thanks Paolo

Sat Nov 23, 2024 10:56 am

Hello, I would not try to tighten the backlash on used gears. If it was setup properly originally, its normal wear.

edit: just reread your post. Do you have the transaxle apart? I have found it next to impossible to set anything without a VW tool that keeps the case from spreading with the bellhousing off. I have a picture of one I fabricated in the gallery.

When I am working with the adjuster rings on a built trans. I mark them, measure depth, turns and will record them.

Sat Nov 23, 2024 11:40 am

Hello, thanks for the reply . The method I’ve used is to bolt the bell housing on, then set preload and measure backlash from the”outside “ by reading off a drive flange which I’ve extended to be the same diameter as the ring gear.
I marked the adjusters before I removed them, but I’m not sure preload was set correctly 15,000 miles ago.
How would you go about setting preload on my worn in bearings.? Should I try to tighten up backlash a little, say to 8 thou? Thanks, Paolo.

Sat Nov 23, 2024 12:53 pm

I would not want to give you wrong information. I set differential preload with no ring gear installed. I am measuring just the turning torque of the differential. Same with Pinion turning torque. I measure it alone.

I recall the manual is specific about new bearing turning torque. I'd expect the preload to go away pretty soon after some miles. Turning torque would diminish at the same time.

The theory behind preload is so you can build with new parts that will settle into spec.

So, it's up to you, but I personally don't change preload or backlash once its been on the road for a period.

It's up to you how to proceed.

edit: If you want to tighten up backlash and preload, turn the left ring in. If you don't back out the right, that should increase preload and might slightly tighten backlash for you. You ask about how much? One notch at a time. Mark where you start.