Trying to decide whether to have the rear axle / differential sand blasted and then gone through. Why??? This truck sat over 20 years in a swampy area. Owner has mixed recollections about running condition when he parked it. 1. Well, the differential leaks out the front (pinion) if it is tipped down. I do not think that is normal. Is this usually sealed or does it breath? 2. The whole thing is really rusted and needs to be sand blasted or ? to remove the rust and crap for painting. I would appreciate suggestions on this subject... 3. I want the gears pulled out, cleaned and examined. They look good but the oil I removed had a silvery sheen but no metal bits. I want this truck to run with no worries about 60 year old parts that may be ready to fail. 4. Do the numbers on the differential mean anything. see attached picture. possibly 8699535 first number may be a 3? Lower number is faint, possibly 185. 5. What about updating the rear axle bearings??? Is there a direct replacement with modern bearings?
I had a previous thread where the differential was identified. Now it is time for the work to begin. thanks all
Last edited by 60ApacheC20; Mon Jul 27 2020 01:03 AM.
Well, I would simply replace the pinion shaft seal and then I'd remove the C clips and slide the axles out. Move the axle bearings with two fingers and feel for any grittiness or odd feeling. If there is none, and if the axle doesn't wobble up and down in those bearings I'd replace the axle seals, put the axles and C clips back, get a new gasket and put the back on. If those axle bearings feel weird and gritty, go to RockAuto and buy yourself 2 new bearings and replace them plus new seals. You can remove the bearings using a special slide hammer puller or ... you can get a 3/4 inch bolt, a couple of heavy duty large washers (one of which you'll cut with a hacksaw to be able to work behind the bearing and pull them out that way. I wouldn't waste my time sandblasting anything. Remove the brake line and clean it with a steel bristle brush plus an old rag with gas to remove any old grease, oil, etc. Then paint it, put it back in the truck and use it. Those gears may be fine. They've worn in happily and with new oil probably won't give you any trouble. See what it does and then make a decision. Wash the pumpkin out with a little gas if you want but if there was no sand, metal chips, etc in there, you may not even need to do that. Check and service the brakes (including parking brake) while you have the axles out.
Looks to be an Eaton HO52 axle, which has full floating hubs/axles. The silvery look to the oil you drained may be swarf from failing bearings or gears. If you saved the oil put a magnet in it and see if anything sticks. I can't be sure from the photo but it appears that there are some pits on the gear facing. Look closely. Get some hi-spot blue and paint some gear teeth to see what sort of pattern you get. If the pattern is OK it probably won't howl. While the cover's off check the differential gears for slop and obvious wear. Washboard roads will do these in after a while. Take your dial indicator and check the ring gear backlash against spec. Then you can pull the carrier bearing caps and have a look. Then pull the pinion, replace the seal and have a look at the pinion bearings. If you have to replace the front pinion bearing, start looking for another axle or pumpkin. That bearing is well over $500 last time I checked. If everything's OK reassemble with new seal and pinion gasket, set the backlash to whatever it was before and put the back cover back on. Usually, these axles are tough as an old boot and rarely give trouble.
I'd be VERY reluctant to get anywhere near that axle with a sandblaster. There's too much danger of getting abrasive material inside, where it's difficult if not impossible to get it all out. Give it a thorough cleanup with a pressure washer, put a pinion seal and hub seals in, and change the gaskets at the front and rear of the banjo housing. It's not uncommon for differential lube to get a silvery color, so unless the lube is gritty feeling when it's rubbed between your fingertips, don't fool with the bearings or the tooth contact pattern of the gears. Once the running fit of a set of used gears is disturbed, it's virtually impossible to avoid a whine. Jerry
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Those axles are very strong. I wouldn't hesitate to install a new pinion seal and run it as is. It will probably outlast most of that truck.
Keep your eyes peeled for those axles at junkyards and on facebook and craigslist. You can usually buy them for pretty cheap. I have about 6 or 8 of those third members in my stash. If my current ring and pinion ever give up the ghost, I'll just unbolt and pull the axles out 6", unbolt and remove the old third, install and bolt in the "new" one, and push the axles back in and bolt the axles back. It's very easy to swap out gear sets with these axles since they have that removable third member.
'66 c10 rust bucket, 350 nv4500 stock bellhousing, '85 c30 front suspension, h072 rear axle with 3/4 ton rear coil springs '67 cj5 225 oddfire motor, time for disc brake conversion, offset rear dana 44, intermediate pedals and steering upgrade '48 3804 frame and bed + '52 6400 cab and front clip + 4bt, need to put them together