Differential oil

[Adrian Harris]

I've started the rebuild of a 222 and decided to try out different weights of oil in the differentials.

This was discussed here a while ago but I'm not sure any consensus was reached as to the likelihood of improvement in movement over rough terrain against increased stress on the drive train.

I have bought three new diffs from Ebay so that, once I've rebuilt the rest of the chassis, I can trial things without needing to alter the setup of the original parts.

Today I loaded 500K weight silicone oil into the centre diff. Its remarkable stuff - think molten glass rather than normal oil. Once fully loaded with oil, it is still possible to turn the drive shafts in opposite directions but it takes a lot of effort.

Having seen the effect this has had on the diff I think I'll try putting 100K weight in the front and rear diffs as a starting point.

I'm guessing to test it I need to try running on tarmac and over obstacles, in order to see if flat running is OK and whether lifting a wheel still strands the 222.

Has any else tried changing the weight of the oil in any of the differentials and if so, what were the results ?

Adrian.

[Steve Norris]

Hi Adrian,
I put putty into my center diff (actually 1 half of milliput so that it would not set ). This allows a little movement in the diff . It does seem to stop all the wheels loosing traction when one wheel lifts off the ground. I may try putty in the front and rear diffs to see how this helps.
Steve

[Patrick O'Donnell]

I have tried all the thickest diff oils there are and none of them stop wheel spin in very muddy terrain, but I have found the perfect soloution. The thickest steam oil I can buy. It is thicker than treacle and twice as sticky and my little 222 has successfully trod the earth at the full sized tank display grounds at Duxford.

[Fabrice Le Roux]

Hi,
Arn't the 222 axles and diffs COTS items (Robbe?)?

The ever ingenious German off-road model truck fraternity are always developing limited-slip or remote lockable diffs. Try posting on a truck board (in English); I have always be delighted by the friendly welcome and faultless grasp of language, even technical descriptions I have recieved.

Just an idea...
cheers
Fabrice
PS I used to be in to R/C 4x4 too!

[Adrian Harris]

The differentials are from the Hobao Hyper 7 buggy.

I'm afraid I've been side-tracked from the 222 by another Sherman so haven't revisited the differential oil question.

It would be good to hear from other owners as to how they feel their 222s aee performing.

Adrian.

[Sean Noonan]

hi guys
adrian - did you have any luck with this problem or find a solution??
steve - did you try milliput in the front / rear how did it perform

my 222 seems to ground itself with ease, im not sure what oil is in there. im thinking not very thick by how easy the 222 stops

my local hobby store said try bluetac ?? seems weird but if it works what the hell.

would i have to do all three diffs as the front and rear are what turns the wheels?? and is it not those that slip and give the traction to the stranded wheel (wheel of the ground)??

also would doing any sort of diff locking (semi lock) put to much strain on the rest of the drive train

sorry this is a bit long winded any help would be greatfull

cheers sean

[Adrian Harris]

Sorry Sean, I haven't touched the 222 in simply ages, so I never tried the thick oil I found - it's probably gone off by now

Adrian.

[Sean Noonan]

thanks adrian
i might just try the (blutac or milliput) in the centre diff, as i have a spare centre diff. it might work or might not.
but what i really want to know is should i do all three diffs just doing the centre one seems counter productive, as its the front and rear diffs that give power to the stranded wheel.
unless im getting it all wrong (which knowing me i am )
cheers sean

[Ad Wouterse]

Hi Sean,

Just blocking the centre diff will do a good job.
In case any wheel looses traction the motor will still continue to run and it will lead power to both the front and rear diffs.
If a front wheel looses traction, the rear wheels will still be able to get the 222 out of the mud and vice versa.
In case both a front and a rear wheel loose traction......good luck

[Sean Noonan]

hi ad
thanks for the advice, i might just lock the centre diff alltogether that way i will allways have drive to the front and rear wheels
cheers sean

[Jan_Donadoni]

Made a damned work !!!
I changed the "oil" in the differentials.
Found some kind of "really hard and sticky grease for differentials".... 1 MILLION
Yes really one million ! Found it in a local model shop. No harder to be found
The difference could be easily felt rotating with the fingers.
I do not hope that it will finally solve the "skidding issue" of the 222 but is the best solution I could reach.
It will for sure put some stress on the whole transmission, but should reduce the problem to it's reasonable minimum.
Maybe it could cause some top speed drop and some more consumption on the batteries (shorter endurance), but the model is not intended for street racing or endurance !

When I have finished putting the grease in all 3 differentials I'll make some tests on flat surfaces and on various obstacles. Thereafter will try to take some filming and post it here.

Stay tuned !

[Ad Wouterse]

Made a damned work !!!
When I have finished putting the grease in all 3 differentials I'll make some tests on flat surfaces and on various obstacles. Thereafter will try to take some filming and post it here.
Stay tuned !

Hi Jan,

Just locking or tightening the centre differential will do the job. If you put 1000 K in the other differentials some part(s) will have to give in.