Differential Question

[Shad0man]

For those that have done the suggested upgrades to your differential i.e. bolts/nuts and pinion shaft bushings or even a simple diff service.

1. Do you typically replace the internal gasket, specifically the one on the inside of the ring gear or do you use them more than once? If you use new do you use them dry or apply a thin film of white grease or ? on them. I have new spares, just curious.
2. I have read of diff leaks. Is the consensus that this can be traced back to when the housing came loose and not an independent issue?
3. At this time I am going use the original 20K weight oil. To what height, meaning how far from the top of the diff housing are you filling the diff case so as to allow for thermal expansion and not create a pressure caused leak.

In my situation, all of my diff bolts were loose with several that had partially backed out and they all came out very easy. FWIW, this was an assembly rather than running issue because it’s only been idled and run moderately using less than 1/2 tank of fuel. And then when the two diffs were opened the gears spider gears within were coated with a film of oil but there no measurable oil within to drain out and no visible leaks so I have no point of reference.

Lastly, is there a consensus on whether the Nylocks are staying tight? Have any of you inspected your upgraded diffs after running your rig for awhile to inspect it?

I ask because within a thread posted not long ago the fellow shared that when he opened his diff, I think because of a diff cup failure that the Nylocks were no longer tight. He speculated that they were budget Nylocks. I purchased quality grade 12.9 bolts and Class 10 nuts so I am asking because I am debating as to whether I want to use Nylocks dry or conventional steel nuts with red Loctite.

Like all of us, after all the work I just want to assemble the diffs and not be concerned about them coming loose again because the secondary damage could be extreme.

My thought process has always been that the oil and heat may affect the Nylocks ability to retain a friction pressure value whereas the red Loctite once cured on a conventional nut will withstand both heat and oil.

Sharing your thoughts, opinions, and experience will be appreciated.

Thank you

 

[Mick Mars]

For those that have done the suggested upgrades to your differential i.e. bolts/nuts and pinion shaft bushings or even a simple diff service.

1. Do you typically replace the internal gasket, specifically the one on the inside of the ring gear or do you use them more than once? If you use new do you use them dry or apply a thin film of white grease or ? on them. I have new spares, just curious.
2. I have read of diff leaks. Is the consensus that this can be traced back to when the housing came loose and not an independent issue?
3. At this time I am going use the original 20K weight oil. To what height, meaning how far from the top of the diff housing are you filling the diff case so as to allow for thermal expansion and not create a pressure caused leak.

In my situation, all of my diff bolts were loose with several that had partially backed out and they all came out very easy. FWIW, this was an assembly rather than running issue because it’s only been idled and run moderately using less than 1/2 tank of fuel. And then when the two diffs were opened the gears spider gears within were coated with a film of oil but there no measurable oil within to drain out and no visible leaks so I have no point of reference.

Lastly, is there a consensus on whether the Nylocks are staying tight? Have any of you inspected your upgraded diffs after running your rig for awhile to inspect it?

I ask because within a thread posted not long ago the fellow shared that when he opened his diff, I think because of a diff cup failure that the Nylocks were no longer tight. He speculated that they were budget Nylocks. I purchased quality grade 12.9 bolts and Class 10 nuts so I am asking because I am debating as to whether I want to use Nylocks dry or conventional steel nuts with red Loctite.

Like all of us, after all the work I just want to assemble the diffs and not be concerned about them coming loose again because the secondary damage could be extreme.

My thought process has always been that the oil and heat may affect the Nylocks ability to retain a friction pressure value whereas the red Loctite once cured on a conventional nut will withstand both heat and oil.

Sharing your thoughts, opinions, and experience will be appreciated.

Thank you

Nothing but a nordlock, forgive my spelling,is gauranted to stay tight.I did not drill my diff housind but just clearenced with a dremmel for nylock nuts.Used 4m×25 m fhsh screw 12.9 from our supplier at work.Got a pack of 50 for 15 bucks.Blue locktite on screws,not on locknut,drop of superglue on locknut, if this does not hold I will slightly "pean" the screws next time,threaded end. I also use a punch to Pean 3 spots on head of screw if you understand.Edge of screw head and housing will have apunch mark to help hold.I reused gasket because they are brand new diffs and yes were basically empty,light coating of diff fluid in there.2 of screws not tight no locktite on any, again quality control.Refilled with 2 million weight diff fluid.Figured cant hurt and working good so far.Found out that if you pull spider gears etc out can be hard to get everything back in but if you use a old side gear on top to hold everything together slips right in.Look at manual and seems like it all needs to go in at onse as a assembly.Strugelled with it before till I figured that out,seems to tight if you piece it together. How did talyor diffcups go for you.Did you have any issue getting bearings on,mine may have been rare specimens .I cant remember the numbers for sure but diff cup shaft where bearing fit is at least 4 to 5 thou oversize and not a slip fit like on primal cups.

 

[Shad0man]

Thank you for the detailed reply.

The only unanswered question is how high did you fill the diff housing with oil? I am just trying to get an idea from a few folks. Any amount would be better than what was in there; LOL. Yes, the quality control during the assembly process was sorely lacking. I feel bad for Dan because the proverbial buck stopped with him. To his credit he is an honorable person and does as needed to make things right. He cares.

Yes, I fully disassembled the diffs and I appreciate you sharing that you found them easier to reassemble as a complete assembled cartridge rather than piece by piece. I will follow your lead.

As for the Taylor diff cups, I have not received them yet. I will let you know my experience with the bearings once they do.

Lastly, unlike you, I drilled the diff housing holes. I considered doing as you did but decided to drill them with a #22 wire drill bit that results in very snug tolerances for the bolts. I read to many people post that could not get the bolts out because they snapped, head stripped, etc. ultimately having to purchase new diff housings. The work in this upgrade is the dremel work to create the reliefs for the nuts and I’d rather not do it again. However, if I were to I’d create a fixture and drop and end mill down rather than doing it slowly by hand. In any case, by drilling the diff housing I can always remove the bolts without the need to drill them out should one break or the head get stripped. Worst case all I would need to do is drill the head off the countersunk bolts which bt design has a centered pilot hole and then using a small punch to tap them out.

Takes care

 

[Mick Mars]

I got a dremmel bit set for 10 or 15 bucks on amazon,backed out 1screw at at a time,to keep chips out.Took maybe 2 or 3 minutes to make clearance for nylock.Made sure nut sat flat on housing.Once all areas good, checked by installing longer screw with nut,disasembled dif,removed cup screws,both sides were tight,cleaned and locktited,blue.No locktite when I took apart but they were tight.I used a bit that was flat on end but it has a "file"like pattern on it to make housing flat and to clear bolt. You cant pour fluid I used in,very thick,used popsickle stick too scoop it in........Side gear will push excess fluid out if to much in there so about top of crosepins max. I think if current mods,nut bolt thing fails I will try 5mm fhsh screw with punch mark.l did this before installing taylor 50 with 4mm,locktight,punch mark with no failure.Almost all carburaters had this on throttle plates and been doing for years on flathead/counter sunk bolts in heavy industry gearboxes at past work,great mechanic secret. Yes Dan seems great,maybe he will adopt me......I wish he could build product in USA so he could keep an eye on things.It is sad to get new shocks with seals backward,transmissions with parts missing.etc.My truck broke within 15 minutes on first run when I bought it because of missing trans parts,almost 500 bucks to fix.Before I forget check servo saver shaft for binding,spent close to1500 bucks before I figured out thats the problem more than servos.

 

[Shad0man]

Thank you

I too considered the 5mm path because I read that at least one other member has done so. Like you, I am going to see how this plays out first.

When I read your earlier post I assumed the oil weight stated was as incorrect, I did not realize you actually used pert near paste.

What was you goal? A firmer lockup or simply what was on hand at the time. One thing for certain is it won’t leak out. Being so thick doesn’t it affect slow speed maneuverability?

 

[Shad0man]

Hi Mick

Just a quick follow up on my earlier diff oil question.

Did you put the thicker diff oil before or after you installed your 50 engine?

What difference have you noticed when compared to the original 20K oil?

Thank you

 

[Mick Mars]

Was spinning 1 rear wheel more,pulling to the left on acceleration.Added after install of 50 ,no difference.Was running unmodified diif when truck ate pinion bearing,thats why truck was down for rebuild of both diffs.Been through 4 diffs before learning about mods.Did front diff with jost locktite and punch marks begining of summer was still good,was brand new never opened just r and r screws and punched.Decided to modify both after rear ate pinion bearing.Have maybe 3 full tanks with taylor plus 2 break in.....again most of that with punch mark front diff.So broke 3 diffs stock motor with bartalone pipe,screws fell out.Zero diff cup issuses with either engine .Was installing taylor cups to avoid issuse but we have talked about bearings....Runing taylor output shafts ,titanium, zero issues.Broke v3 taylor f/r shaft and 3 primal and of course the reverse parts missing cause first failure on first run brand new. Other than servos for steering which was from servo savor being bad from purchase truck isgreat.full grave digger out too..Can not recamend the non primal steering stuff other tnan arms from taylor with oversize bolts,driil and tap plus washers.They froze up also burnt up primal 180 servo.The primal hd links etc work great and run beast 2000 servos witch are overkill,have to run tight servo saver ,not real tight or they overtake servo saver.
Oh did not drill out threads in housing because I consider nylocks as a backup just clearanced and made sure nut sat flat .So still realying on locktite etc ,but a regular inspection will happen.It seems like a lot of work but I enjoy the mechanical part of hobby too. Pretty quick now with all the practice...I can pull trans out and take apart in 45 min,rebuild and install the same,but always let locktite cure 24 hours.

 

[Shad0man]

Thank you Mick

I do recall it favoring one side over the other when accelerating during the brief time we ran it. I have some 1m diff oil that I will put it in. It does not sound like it fixes it, and even more so with the 50 as it’s a torque monster.

Do you feel that you’ve come to terms with the limitations and now exercise your rig with this understanding or do you simply exercise and fix as needed.

It was nice to read that you’ve lost no diff cups and that you now seem to have a handle on the pervasive servicing of the diffs. Because servicing them is a fair amount of work I’d like them to be relatively issue free and be able to do an annual service on them. We shall see. The upgrades will certainly help.

My original servo saver did not work. The aluminum shaft had been dug into so it was effectively a fixed in place connection point. Initially I sanded and polished the shaft but was not able to get it 100% so I replaced the shaft with Dan’s stainless steel one and also replaced the 2 bearings with the bronze bushings he sells. Even without time on the rig yet it, my bench testing indicates that it is operating as it should so anticipate no issue servo saver related issues.

Thank you again for you comments