LT transfer case oil seal

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02 Nov 2012 21:26 #1 by dandjcr
dandjcr created the topic: LT transfer case oil seal
Forum Home > On the Road > LT transfer case oil seal

OKA 262
Member
Posts: 27
Hi all
I hope you can help. The rear oil seal on my Rockwell TC is leaking. The one behind the hand brake drum.
Can someone provide the part number plaese.
Stay well
Vidas
August 2, 2011 at 10:43 PM Flag Quote & Reply

Peter & Sandra James Oka 374
Member
Posts: 413
Vidas
You can either pull it out and take it to your local bearing supplies and they will measure it and provide a replacement or ring Paul Nott at East coast Oka and he will post one to you.
Peter
--
Oka 374 LT Van

August 3, 2011 at 7:26 AM Flag Quote & Reply

Aussie Bight Expeditions
Member
Posts: 109
Hi Vidas,
The seal I have listed from the last twice I have replaced this seal in three different rockwelltransfer cases for behind the hand brake has been National 415483. Any Bearing shop will have or get or phone Paul as he might be the quickest any way.
ABE TONY
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August 3, 2011 at 1:05 PM Flag Quote & Reply

OKA 262
Member
Posts: 27
thanks for your prompt replies.
I phoned Oka in West Oz and they thought (?) there were two oil seals behind the hand brake.
I will order the Nat 415483
Stay well
Vidas


August 3, 2011 at 8:24 PM Flag Quote & Reply

Aussie Bight Expeditions
Member
Posts: 109
Vidas,
You will wonder what you have opened when you go to this, as it is a strange set up. There is what appears to be a slightly bent plate (domed or is that doomed? ) in there to get out, and I think there is a round wire you have to dig out first from memory, been a while since I have done one. Then to get the plate out which is sealed with a good silastic, which makes it near impossible to remove, so I drilled a hole in the plate small and used a panel beaters hammer, that I have that has a screw dive on it. Otherwise put a screw in it and get some device to pull back on it. If there is an easier way, I would like to know myself.
I have normally found that they leak because they are a silly set up with the hand brake drum being on the end and it is not supported. Both my OKA's now have a support bearing added to the back of the drum. Now only have a problem when the support bearing gives up going around. There is a thread on this subject in the forum section
As far as I Iknow there are quite a few different variations to the Rockwell Transfer cases and I have had 2 different types in the 2 OKA's when OKA made them, one had a 50 mm hand brake drum and lighter internals which did bearings in regularly and have replaced that with a 75 mm hand brake one that is a lot heaver in bearings and gears and I have another one that is heavy inside and uses different bearings to the last one as it was used a drive for fire units. Makes life interesting when one pulls them apart inside. All the cases are the same.
Hopefully yours is the same seal as mine
ABE TONY
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August 4, 2011 at 10:43 AM Flag Quote & Reply

OKA 262
Member
Posts: 27
Hi Aussie Bight
Thanks for that. I recall now that my hand brake is not the "standard" and was replaced by the original owner.
It works very well and will hold the vehicle on any slope.
I have replaced the oil with TF 450 (SAE 50) and the leake has stopped/slowed. Previous oil was SAE 30 which is incorrect for the Rockwell but fine for the NP205 box.
Will wait and see if it gets worse.
Stay well
Vidas


August 4, 2011 at 10:16 PM Flag Quote & Reply

Aussie Bight Expeditions
Member
Posts: 109
Vidas
I actually use diff oil Caltex Thuban gear oil EP 80w - 90 and beef that up with Morey's Heavy duty Stabilizer @ 25% so if it does still leak you have a better option as I was told to do that from an ex spanner man, I knew in America now retired who used to rebuild them for various people.
My temperature in the transfer case runs cooler than the Gearbox not by much, but about 5 degrees C

ABE TONY
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August 5, 2011 at 10:12 AM Flag Quote & Reply

OKA 262
Member
Posts: 27
Hi Aussie
80/90 in the TC is an interesting option.
thanks
Vidas
August 7, 2011 at 8:21 PM Flag Quote & Reply

Peter & Sandra James Oka 374
Member
Posts: 413
I've been running a full synthetic 90 grade with added teflon in the transfer and gearbox since I bought 374 last November. It has dropped the temps considerably. The gearbox is stiff till it warms up but then works ok.
--
Oka 374 LT Van

August 8, 2011 at 7:14 AM

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25 Jul 2013 22:38 #2 by OKA in Africa
OKA in Africa replied the topic: LT transfer case oil seal
Hello,

I'd like to finally get to the long pending work and change the LT transfer case oil seal behind the parking brake drum. Long time ago I think I did read a longer post in the forum describing the work to be done. Is there another description apart from the one above?

Thank you and best regards

OKA #327 in Africa
www.oka4wd.com/forum/members-vehicles-pu...47-oka-327-in-africa

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26 Jul 2013 21:29 #3 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: LT transfer case oil seal
For a "normal" Rockwell transfer case then just remove the welsh plug (metal plug sealing the centre of the handbrake drum), it can be held in with a wire type circlip but most are coated in silicon and then tapped in which can make them hard to remove. Easiest removal is to drill a small hole in the centre and screw a Tek or self tapping screw into the hole which give something to grip to pull it out.
Then undo the bolt allowing the handbrake drum to be removed. There have been all sorts of mods done to attempt to stop oil seeping past the seal but as the weight of the handbrake drum is hanging right on the end of the shaft it will wobble minutely even with new bearings and older worn bearings cause an even bigger wobble which means seals don't last long.
The whole Rockwell transfer case in the Oka is nothing but an abortion anyway and ideally should be replaced with a better engineered solution.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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12 Nov 2013 20:59 #4 by OKA in Africa
OKA in Africa replied the topic: LT transfer case oil seal
Thanks for the feedback.
I have replaced the oil seal behind the hand brake (which is supposed to be a National 415483) with a CR 26190 oil seal. It worked fine for the last 7000km and stopped leaking.

Thank you and best regards

OKA #327 in Africa
www.oka4wd.com/forum/members-vehicles-pu...47-oka-327-in-africa

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