Advised Rear Diff fluid # thickness? Use Stock?

[KewlToy]

Advised Rear Diff fluid # thickness? Use Stock?

How full?

[Arakon]

10k-30k front, 5k-7k rear. Fill to the crossed pins.

[KewlToy]

OK, Thanks!

[Outkast187]

I have also had success with 2k in the rear, I keep front 20-30k though.

[KewlToy]

Thanks guys!

[mr.chevelle72]

im running 10k in the front and 5 to 7 in the rear depending on the track conditions.

[KewlToy]

I'm seeing a wide range of numbers... I'm pretty much in the middle.
Thanks for the info guys!

[Uh1medic]

Advice for low traction dirt track? I know why 2wd becomes more and more unstable in the rear with increasing fluid thickness.

[slodustin]

Originally when I build the truck I put 30k in the front diff. and was runnining indoor clay. Now I have since moved back home and have started running my home track which is a hardpan soil. Hard pack sand with tons of loose sand on top. Extremly slippery, it's like driving on concrete with sand sprinkled on top. Question is should I come down in front diff. wt. for these conditions.

[KewlToy]

Uh1medic:
I wish I could give you a more definitive answer:
This article is regarded as the tuning bible by many: (it's a long read, but first check the short summary's at the end)
THE Guide - JQ PRODUCTS

slodustin: 30k in the front is thick, compared to many of the other numbers I've seen.
I'm about to try out my new RCshox 2-stage shock piston valves. If these are as good as I've heard, something like that should help keep your tires planted. If you haven't weighted yours yet, consider additional weight.

[slodustin]

@kewltoy I ran my truck today with Rc shox 2stage pistons and the v2 cdiff. For the fist time. 30k up front worked good on
indoor clay. But now that I've put the cdiff in I'm pushing on outdoor track. I think dropping down to 5k diff oil should help. Loving the new Rc shox products btw. I can drive way more aggressive.

[KewlToy]

Originally Posted by slodustin

@kewltoy I ran my truck today with Rc shox 2stage pistons and the v2 cdiff. For the fist time. 30k up front worked good on
indoor clay. But now that I've put the cdiff in I'm pushing on outdoor track. I think dropping down to 5k diff oil should help. Loving the new Rc shox products btw. I can drive way more aggressive.

Thanks for the feedback info.
I'm hoping to be able to try my RCshox 2-stage pistons and c-diff today.
Keep us informed on how the tuning goes.

[triple b]

Kewltoy.....I am going to high jack your therad and ask a diff oil related question....

How ofter do you guy change the diff oil.......... i am running 30K front 7K rear indoor clay and I have 30 + battery packs through mine i have noticed very little resistance in the diff when spinning the wheel by hand........also a lake of foward bite.

[KewlToy]

Originally Posted by triple b

Kewltoy.....I am going to high jack your therad and ask a diff oil related question....

How ofter do you guy change the diff oil.......... i am running 30K front 7K rear indoor clay and I have 30 + battery packs through mine i have noticed very little resistance in the diff when spinning the wheel by hand........also a lake of foward bite.

No problem.
I'm curious also.

As to your question: 30packs and changes in performance are both "past prime" indicators.

Some guys change fluids as soon as 5-10 packs.
I usually wait nearly as long as you have, but I'm just now developing driving skills that allow for sustained faster speeds.

Ideally: if you notice a significant difference after a change, you've waited too long.
If you notice only slight performance changes, your spot on.
Tracks, heat, and driving style can make a huge difference.

[slodustin]

The two stage pistons worked out great. I'm running the Exo chassis so with the extra weight I went 30fr 25rr and it was a good balance. The particular outdoor track I was on had about 100' straight with little bumps all the way down. Truck tracked straight under throttle with out skipping around. This is we're the center diff also helped out. Coming out of the 180* turn onto the straight I felt I could also be more aggressive on the throttle. Though I was running 30k diff fluid in the front there is a push to the truck. A change to 5k should fix that. Overal this is a totally different truck now! Also was running the overdrive pulley in the front which seemed to make the front tires balloon excessively with the cdiff.

[SMR 510RR]

I just got my Cdiff up and running, I put in 7k front and 5k rear but still have a little push on turn in and off throttle turning. I am going to 5k front and rear, truck is so much more planted with the cdiff its not even funny! Awesome upgrade.

Still learning that I can get on the throttle much earlier without the risk of spinning, hard to break that habit. Also, I originally had mine locked down too tight, make sure that the center diff will allow the front and rear to spin independent or else you are just locked up. I ended up about 2 turns out from full spring compression to get the right feel from the diff.

[KewlToy]

Originally Posted by SMR 510RR

I just got my Cdiff up and running, I put in 7k front and 5k rear but still have a little push on turn in and off throttle turning. I am going to 5k front and rear, truck is so much more planted with the cdiff its not even funny! Awesome upgrade.

Still learning that I can get on the throttle much earlier without the risk of spinning, hard to break that habit. Also, I originally had mine locked down too tight, make sure that the center diff will allow the front and rear to spin independent or else you are just locked up. I ended up about 2 turns out from full spring compression to get the right feel from the diff.

Nice report, Thanks!

[KewlToy]

Originally Posted by slodustin

The two stage pistons worked out great. I'm running the Exo chassis so with the extra weight I went 30fr 25rr and it was a good balance. The particular outdoor track I was on had about 100' straight with little bumps all the way down. Truck tracked straight under throttle with out skipping around. This is we're the center diff also helped out. Coming out of the 180* turn onto the straight I felt I could also be more aggressive on the throttle. Though I was running 30k diff fluid in the front there is a push to the truck. A change to 5k should fix that. Overal this is a totally different truck now! Also was running the overdrive pulley in the front which seemed to make the front tires balloon excessively with the cdiff.

I ended up with the V1>V2 upgrade kit, rather than the regular V2 kit that I need. It'll be a couple of weeks before I can test the RCshox c-diff (vacation).
It's good to see your truck performance improve!

[SMR 510RR]

Originally Posted by KewlToy

Nice report, Thanks!

No worries, you will like it!

[DiggyStyle]

From all the advice I got, I ended up using 30k front and 7k rear. I haven't drove it yet but will post up after I do.

I have a question though for anyone who can answer: What if you were to get a little of the 30k diff oil onto the outside of the main diff gear (into the teeth)? It's kind of 'tacky' but it's still a lube, right? Will this cause any problems in the tranny?

I plan to buy another two sets of diffs; so I can have one set clean and rebuilt and waiting while the others are in the truck, that way I'll always have one to swap out when it comes time to rebuild with less down-time.