[Flade]

I‘m getting ready to replace the bearing s and seals on my 68 8” axle.

Axle is apart, blasted, painted, and the new Traction loc with 3.4 gears is ready to go together. Just need to install the new bearings. I have a few questions there.

1. The service manual and all the videos I have watched say to cut off or punch the spacer so it can be removed before pressing off the bearing, but on install of the new ones the spacer is pressed on with the bearing. Anyone know why you just don’t press them off together? Seems like extra work for nothing, but Ford obviously had a reason.

2. Should I use oil or other lubricant on the axle before pressing on the new bearing so it goes on smoothly?

3. How do I know when it is fully on in the right position? Is there some type of positive stop? I don’t want to press too hard and damage it, but I want to make sure it is fully on too.

4. Should I use sealant on the gaskets either side of the backing plate or install them dry?

5. What is the preferred lubricant for a traction loc these days?

6. 8 & 9“ rears sent me friction modifier For the traction loc, Do I use the full bottle?

 

[sheza65]

1) Cutting makes it easier to remove & not bind.

2) You can, but the way I look at it is oil is just filling the "gap" (making it tighter). Warm the bearing & cool the axle to help it slip on.

3) There is a positive stop.

4) Dry. They just keep dust/dirt out.

5) 85W-140, API GL-6 rated conventional (non-synthetic) gear oil with friction modifier.

6) You can use it all. Some people put in half a bottle & increase/adjust as needed.

 

[j persons]

1) Cutting makes it easier to remove & not bind.

2) You can, but the way I look at it is oil is just filling the "gap" (making it tighter). Warm the bearing & cool the axle to help it slip on.

3) There is a positive stop.

4) Dry. They just keep dust/dirt out.

5) 85W-140, API GL-6 rated conventional (non-synthetic) gear oil with friction modifier.

6) You can use it all. Some people put in half a bottle & increase/adjust as needed.

Why the GL-6 non synthetic? I've have very good luck using Redline synth GL-5 75W90 in 8.8 clutch type diffs. Also the Redline doesn't require any friction modifier.

 

[Flade]

1) Cutting makes it easier to remove & not bind.

2) You can, but the way I look at it is oil is just filling the "gap" (making it tighter). Warm the bearing & cool the axle to help it slip on.

3) There is a positive stop.

4) Dry. They just keep dust/dirt out.

5) 85W-140, API GL-6 rated conventional (non-synthetic) gear oil with friction modifier.

6) You can use it all. Some people put in half a bottle & increase/adjust as needed.

Thanks for the detailed answers! How big a bottle of gear oil should I buy?

 

[sheza65]

Thanks for the detailed answers! How big a bottle of gear oil should I buy?

You're welcome.

Three quarts is sufficent for an 8". Fill it until comes out the filler hole.

 

[sheza65]

Why the GL-6 non synthetic? I've have very good luck using Redline synth GL-5 75W90 in 8.8 clutch type diffs. Also the Redline doesn't require any friction modifier.

An 8.8" is a completely different gearset. What it comes down to is the 8" & 9" weren't designed for it. Synthetics were first used several years after the 9" was discontinued & never validated on these gears. The oil needs to be thicker to provide cushion & proper cooling. Here's a good page that sheds some light on this topic:

Why Run Conventional Gear Oil?

www.currieenterprises.com

 

[5speed65]

If you have a axle or driveshaft shop close by I’d recommend having them install the bearings

 

[j persons]

An 8.8" is a completely different gearset. What it comes down to is the 8" & 9" weren't designed for it. Synthetics were first used several years after the 9" was discontinued & never validated on these gears. The oil needs to be thicker to provide cushion & proper cooling. Here's a good page that sheds some light on this topic:

Why Run Conventional Gear Oil?

www.currieenterprises.com

I looked up what gear oil for Mosler, Strange, and Motive Gear, and they all said 80W90 gear oil and didn't specify conventional or synthetic. What is somewhat strange is that Currie uses Motive Gear R&P in their axle assemblies and their lube recommendation is different than Motive Gear. One thing I do know, a heavier gear oil will dampen the majority of gear noise from the R&P