Vader93

And hopefully a D250 set up for great fuel mileage. Hell i don't know what or how I've been doing it but with my D350 with the 5x18s driving with a light foot and 70mph highway speeds i was getting 21mpg after i installed the NV and dual disc.

thrashingcows

Was messing around with my NV4500 top cover, and shift tower today....

https://www.dieseltruckresource.com/...3/#post3294059

thrashingcows

Well I have been having some weird diff issues for a while now, been getting worse over the last few months. Felt as though the power loc unit in the rear D70 was not working right, or was failing...which it shouldn't because I had it all rebuilt when I had the diffs re-geared back in Nov/2014.

But it also kind of felt like it could be coming from the front end. Since we have a 1000 mile trip planned in the crewcab in a couple weeks I wanted to check the front bearings and seals to make sure they were all good. I figured in two years since the big front end rebuild that this would be a simple check, toss some new grease in a few places and be done with it....well things seldom go as planned.

Here's the pass side....



Front bearing.....



you can see the inner seal was cooked right out!



Lot of water had made it in.



The drivers side was a lot better...no rustiness, but still a lot of dark contaminated grease.

thrashingcows

It was about 6pm yesterday evening and luckily the parts store just up the road from me was open until 7pm. Was just planning on doing the rear seal, but the old Timken bearings and cups were looking worse for wear, so figured I'd grab all new ones. I had forgotten that I did not replace them when i re-did the front end before.






Unfortunately they did not carry timken bearings...SKF, and made in China/Japan...But I couldn't be picky right now.



So worked on it until 11:30pm last night, cleaning, and replacing everything. Took it around the block before coming in. It was when I was in the shower that I realized i did not set the end play on the front bearing properly. I grabbed my FSM and checked...sure enough I was going to have to re-do it in the morning.

So according to the FSm you need to tighten the hub bearing to 50ft/lbs to seat them. Then back off and rotate the rotor/hub assembly when tighten to 31-39 ft/lbs. Once tight then you back off the nut 135*-150*....I did a 90* then reset and did a 45*. Worked out almost perfect!

Mike L

Man, that is some fugly stuff going on with those bearings and seals. Thoughts on where/how the water intrusion occurred? A little too much time under water playing in the mud? kidding, just kidding!

thrashingcows

And here's something I have been doing since converting the Crew to 4wd....



Helps keep water and debris from working there way in around the bolts. Even my diff guy loved it and was going to start doing it to every axle he worked on, or built.

thrashingcows

Both side the rear seals were absolutely cooked out. There was no sealing lip left and the inner spring was just laying inside the rear of the hub. My guess, and hope, is that those old bearings were just plain worn out and was allowing too much slop in the hub and that eventually killed the seals.

thrashingcows

So once the front end was back together I decided to go have a visit with my diff guy. I explained what had been happening, and right way he says it's clutch chatter from my powerloc. I mentioned that I kind of figured that might be what my problem was, and just a few weeks ago i had switched to synthetic fluid with an additive, He asked if it had been getting worse...Yes it had!

This guy is a rare individual...he's as OCD and passionate about diffs, like we are about our 1st gen's. And he knows his stuff! There are very few people I would trust to work on any of my vehicles, or stuff...he is one of the few.

Anyway he explains how the synthetic fluid really isn't as good as they say, but does have it's applications, but most everyday driving is not the right place for it, and that a ton of his diff work is from OE manufacturers putting synthetic in their diffs...and they plumb wear out right as the warranty ends. Well he tells me to go get some Lucas 85W140, and Motocraft diff additive (1.5 needed) and this will solve my issues. He says any other additive will just cause issues....and if you do want to run synthetic then you need to add at least 2x's or even 3x's the additive.



Will find out tomorrow after I drive to work.

bigragu

That's all I've ever used right there, that Lucas, same weight, too. For front and rear diffs, and the Lucas 80/90 for the NP205. Can't remember brand name on the 8 oz. of friction modifier, starts with a C, get it from NAPA. My Father in Law was a diesel mechanic for years with Kenworth, and the mechanics in their shop all swore by Lucas Products. They sometimes used the Lucas oil stabilizer as the friction modifier for the big rig rear ends

thrashingcows

Thanks...that's good to know that others have been using these products...with success....

diesel402004

Let us know the results if you could. My diff chatter is driving me nuts and nothing has helped: even new clutches😬

Mike L

diesel402004, out of curiosity, do you currently have synthetic in your dif.?

Cheers!

Mike

diesel402004

No. I've only run the normal mineral 75-90 (with addition additive) in my diffs all these years

bigragu

Well, TC, how did the new Lucas products do in the battle against diff chatter? Sold on it? If it worked out for you, the next time you change out your power steering fluid, try using the Lucas PS stop leak in the whole canister- mine took 12oz. Stiffened the steering up some, it seemed.

oliver foster

I would be careful adding much Lucas PS stop leak in a cold climate, as it is really thick.
I have blown a PS hose on my old '94 2500 years go when it was really cold [-25F*] do to the thicker Lucas oil.