Hot Racing sealed differential review

[cunawarit]

I get leakage inside my tranny too, and out the outdrives... Looking forward to not having to deal with that anymore

[PBO]

My 30k hasn't leaked a bit from several days ago.

Will 30k be enough once you've run it?

[cunawarit]

I'm starting with 10K, mind you, I have a Bandit and I am racing.

I'm thinking that with the much smaller buggy wheels I won't need too heavy an oil.

Got the oil, but the diff is still in its way to me.

[O.G.]

Will 30k be enough once you've run it?

30k is what I use with my track slash so I'll say yes at this point but I'm not for sure yet. I haven't ran it yet... I do know I worked up from 5k to 15k and settled on 30k for the track, and the Slash handles well on the street with 30k.

It did not handle well on the street with 5k and 15k; the trucks rear end seemed loose or squirrely on acceleration.

[O.G.]

I'm starting with 10K, mind you, I have a Bandit and I am racing.

I'm thinking that with the much smaller buggy wheels I won't need too heavy an oil.

Got the oil, but the diff is still in its way to me.

10k was too loose for my taste but there are a lot of variables with different tracks, tires etc... I mixed 5k with 30k and came up with what I assumed to be 15k (or 17.5k if you want to get more specific). The AE 30k seemed very thick at room temperature and formed a small mound on the gears for a while before it leveled out.

[O.G.]

Well as it turns out, the differential began leaking after being full for a week. It wasn't really a leak, but more of a seep out of the output shaft which means it will probably leak more when the diff is up and running. Not the greatest pic but you get the idea:

[O.G.]

Here are a few pics of what the inside of your transmission case will look like a few weeks/months after you stuff the diff with red wheel bearing grease. What a mess, but hey, everything is well lubricated.

Stock differential itself.



Inside the transmission case. Pictured is the idler gear (R), and top shaft gear (L).



Another view of the case, this time showing the bottom hole with the tape still installed.



Pic of the spur and pinion prior to disassembly



Spur gear off showing the top shaft and top shaft pin. This is the pin that often shears off.




New bearings of course

[AZ Racer X]

Man that is to bad. Any thoughts on maybe RTV or Ace hardware having a replacement ring ? I was really holding hope for this as being a decent upgrade :s

[O.G.]

Don't forget the teflon washers.



New diff and old gears installed inside the HR transmission case.



Here is the spur gear side of the case installed with a screw scavenged from the old case. The spur rubbed this screw head so I had to take it all apart again and re-install with a flat-head screw.

[scootroc]

Man that is to bad. Any thoughts on maybe RTV or Ace hardware having a replacement ring ? I was really holding hope for this as being a decent upgrade :s

I think there's bound to be some seepage whenever you're dealing with seals/lubricants. My FLM diff seeps too - not a big deal and seals much more effectively than stock.

[cunawarit]

Finally got mine, here it is assembled:



10k might be a little light after all. Let's see how it works at the track next week.

[O.G.]

10k might be a little light after all. Let's see how it works at the track next week.

What truck are you running it in? Let me know how you like it.

[cunawarit]

What truck are you running it in? Let me know how you like it.

A Bandit, I'll let you know how it goes. I'm running the Hot Racing tranny case as well.

[rag6]

Og, was that 30k in the hr diff? Maybe a heavier wt like 50k will stay in a little better...

[O.G.]

A Bandit, I'll let you know how it goes. I'm running the Hot Racing tranny case as well.

Is that the Bandit you've been racing from your build thread?

[O.G.]

Og, was that 30k in the hr diff? Maybe a heavier wt like 50k will stay in a little better...

Yes it's Associated 30k silicone oil.

Does anyone know how much this stuff thins out as it warms up? I got some on my fingers and it acted like it was melting and it reminded me of the silicone gunk I use for fly fishing which has the same properties.

Any ideas?

[cunawarit]

Is that the Bandit you've been racing from your build thread?

Correct, that would be the one

Sent from my GT-I9000 using Tapatalk 2

[cunawarit]

BTW, my diff seeps oils a little too, less than yours judging from the pic but a little nonetheless.

Seems to be out of the bolts. Understandable, as the bolts don't seem to be covered by the gasket unlike some of the modern sealed gear diffs for race buggies and trucks.

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[cunawarit]

Here is where mine seeps:

[scootroc]

Here is where mine seeps:

That is where mine seeps also. I'm using 120k.
Was thinking it was a displacement issue.

[cunawarit]

I've used some thread seal tape to try and minimize the seepage.

[cunawarit]

I think the issue may be the gasket, which is understandable as Hot Racing is adapting a design that was never meant to be sealed.

But look at the gasket for the Proline diff:



The bolts are sealed and never exposed to the oil.

PS: Slightly off topic, but where are Hot Racing based? From their website they have a Po Box in California. But are they a US company? They seem to be making an insanely high number of parts.

Their website really doesn't say much other than listing parts.

[scootroc]

Possibly a gasket issue; however, I've been using the same technology in my FLM diff for at least 2 years, so the sealed diff does work and hold in oil.

Not sure on HR headquarters. Can't find a phone number as I would like to talk to a tech about another product.

[mattkd55]

Just received mine today and i have a question. where does the little o rings

[cunawarit]

Put them on the output shaft before assembly. See inside the case there's room for them to fit.

I hope that's clear :screwy: I'd normally draw a diagram but I'm on my phone.

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[mattkd55]

thanks alot thats what i thought

Put them on the output shaft before assembly. See inside the case there's room for them to fit.

I hope that's clear :screwy: I'd normally draw a diagram but I'm on my phone.

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[mattkd55]

thanks alot thats what i thought

Put them on the output shaft before assembly. See inside the case there's room for them to fit.

I hope that's clear :screwy: I'd normally draw a diagram but I'm on my phone.

Sent from my GT-I9000 using Tapatalk 2

[O.G.]

Cunawarit, I believe they're manufactured in southeast asia somewhere. I think the package for the transmission case said made in china.

[cunawarit]

The tape may have worked, it has been a couple of days and it is still absolutely bone dry with my light 10k oil. It is worth mentioning that I tried to apply it as high on the head as possible (this isn't that clearly shown on the pic sadly).

[rag6]

^^^ I had a feeling that the oil was gonna seep out of the bolt threads(Told ya so!). You can also use some blue rtv sealant from the auto parts store.

[cunawarit]

rag, I left it for quite a long time and it didn't seep out again Good tip on the rtv sealant, the thread seal tape seems to work well. As I said, I ended up applying it right to the edge of the head... Unlike the pic I showed

Overall I am happy, I don't mind having to seal the bolts.

[O.G.]

I've used some thread seal tape to try and minimize the seepage.

I'm going to try this next time I open it up. That could make a huge difference.

Sent from my Super-Kindle

[cunawarit]

Just remember to apply it right up to here:



Don't follow my first example I redid it right after I took that shot.

[cunawarit]

FWIW, 10k worked great for the Bandit. I was actually the fastest I've ever been with this new diff and some other changes it allowed me to make.

Very pleased! More pleased than I ever thought I'd be to be honest... I can't quite believe I ran a fully open diff for racing for so long, $28 plus delivery gives you what amounts to a new car in terms of increased performance.

Everyone, GET THIS! NOW!

[O.G.]

Now that's a ringing endorsement if I've ever heard one. I'm glad you like it, same here.

[Kitteh298]

I'm using big 2.8 trenchers in the back of mine right now, what kind of oil could I use with this differential for bashing, street, dirt, and grass. I actually use the washer mod right now and it works really well. Just wondering if this is worth buying? Any better than what I'm running now?

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[cunawarit]

With 2.8 trenchers you'll need something way heavier than my 10k

If I were you I'd just go for 100k, it will stay in better and reduce your service intervals.

[rag6]

Kitteh, after a while of using the washer mod, I had issues with the internal diff gears self destructing. It worked for a good while though. Hope it doesnt happen to you. If you do start having problems, replace the entire diff with new parts and washers, and it will work well for awhile again.

[teamfx3]

FYI, base your gear oil selection on your track temps. I just installed the HR sealed diff in mine last night with 30k gear oil as was suggested above and I may as well have installed a spool! In the low 30* temps at our indoor track that oil was like molasses causing the diff to not diff and constantly want to spin my truck out. Tough lesson learned for me today.

[cunawarit]

ok good tip teamfx3.

As I said before, 10k works great for me. I don't know the temperature, it is winter. But we race in a relatively warm basketball court.