Jack O'brien of O'brien 4 Wheels West is still in business

Guys,
I just got off the phone with Jack O'brien who makes the O'brien Rockeater gears for D18 and D20 transfer cases. He is still alive and well, still running his business in Roseville CA, although he did mention that he has been getting cancer treatments that slow him down some.

He told me that he has just finished making this year's run of Rockeater gears, in 3.59, 4.01 and I think the 4.68 ratios. He has finished with the gear cutting, and dropped these off at the heat treater's facility in Stockton. After the heat treating, he finishes the tooth contours and dimensions with CNC diamond grinding equipment.

I have a D18 TC with a set of the 3.59 gears, with the intermediate gear in bad shape needing a replacement. He told me the gear would be available by about April, he is out of stock on that particular gear right now.

I have seen a couple of other threads on this list of people wondering if Jack were still around, he is and the phone # 916 773 3278 is still good.

Don

 

Thanks for posting that up, Don. I've been mulling going with some lower gears in my t-case.

 

Wow! Glad to hear he's still around!

I read something on his 4:01 gears for the Dana 18 a while back.

 

Be aware that installing the 4.01 and the 4.68 gears require extensive case modification. You have to cut a window out of the top of the case and weld a patch over it to allow clearance for the much larger intermediate gear.
The 3.59 set does not require this, I think depending on the case used some light clearance grinding is all.

Don

 

I don't know much about his gears but do you still get to keep the direct drive? (high and low)

 

Yes you do.

 

thank you I wasn't sure.

 

Doesn't effect the warn od does it?

 

Two of his gear sets (3.06, 3.59) will accept a Warn OD but will require using a custom bowl gear for the OD that Jack can supply. These 2 gear sets use a 24 tooth gear on the transmission output shaft, so the bowl gear has to be a 24 tooth and not the standard 29 tooth.

In my earlier posts I referred to the 4.01 and 4.68 gear set which was not correct, these are actually 4.06 and 4.86 ratios. These two sets will NOT accept the Warn OD, because the transmission output gear is too small. I think Jack told me these are 20 tooth gears.

Jack is currently working on this year's run of 500 gearsets, and he expects them to be ready by the April time frame. These are usually sold out again by Fall.

Don

 

Just curious as I run 4.88's. Can't live without my od. Best thing I ever did. Deeper t-case gearing would be nice though.

 

thanx

 

I have been thinking about a set of Jack's gears for at least a decade but I still think adapting the low range unit from a Quadratrac BW 1339 to the back of the D18 would be a much better solution and offer an even lower ratio (ie 8:1)-at which point a person could run 3.07 axle gears and still have an extremely low CR, eliminate the relatively weak OD, and get some good road mileage. The big problem with that is that most D18's are likely still behind some sort of 134 power that wouldn't do well with 3.07's and hence, there would be a very limited audience for the product.

 

Have you seen this?

http://homersgarage.wordpress.com/2...ations-or-how-to-make-60-year-old-stuff-rock/

 

I think Jack makes a good product but it is pricey and requires some serious mods to the transfer case on some applications. In your case with the M22 wide ratio box at either 2.56 or 2.98 low..........why not have a Granny 4-speed in there at a 6.32 or greater low gear?
If you need the offset drive.........Take a D-20 large hole case that is stronger and either put the D-18 / 2.46 gears in it or a tera-low 3.15 set............with a 3.07 gear in the back , thats still a 61.11 Crawl ratio........and you can still retain the Warn Overdrive......... with 4.11s thats 81.82:1...............lots of ways to get there....................Just a thought.

 

I have 3 of each SM 420's and 465's sitting in the shop and have given plenty of thought towards installing one but really don't want that extra 100 lbs+ weight, that and the AGE M22 is just a pleasure to row, even if the low gear is 2.56. It is also pretty much bullet proof with the high nickle gears, nodular iron midplate and the M22 bevel cut. My D18 is already built on a D20 case and has a set of TeraLow 3.15 gears.

However, the low range unit gears from a BW 1339 make a Warn OD look just plain wimpy and it is the Warn that I am worried about. The 1339 has a pretty decent track record (if maintained) and was used behind the 401 so it is obviously up to the task. The Warn is the weak link in my drive train and a rather expensive one at that.

I had not seen the Homer's Garage posting but that is exactly what I would like to do. Nothing like having your cake and eating it too. Seems to me that an adapter for that would be a lot easier install than cuting and welding cast iron and then worrying about cracks.

 

No Question ..........shifting the M22 versus one of these Truck transmissions would be a Joy!.............& the weight may make a difference in some applications.
Have you ever broken a Warn OD? I mean don't get me wrong , anything can be broken with enough applied torque related energy !.........I just have never had an issue with mine...........

 

I haven't either and would be the first to admit they can likely stand more than their 300 ft lb rating. That said, it has never been engaged in the 3B when putting the skinny to the floor.

 

I had a '54 Willys Utility Wagon with 33's and the stock flathead 6 that had a Warn OD. I wheeled it pretty hard and never had a problem with the OD. My current Jeep on 35's with a Saturn gets romped pretty good offroad and I haven't had any problems with it other than crappy manufacturing (broken shift fork, not properly hardened internal parts). Suffice to say I've never broken one from hard wheeling and I use it a lot in low range.