3.54 in a kb2 rear housing...Whaaat?


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Post Mon Aug 26, 2019 12:52 am

3.54 in a kb2 rear housing...Whaaat?

rear end modified.gif


Well, it now exists. This is a picture of a 3.54 ring and pinion from a 34 ford grafted into a kb2 rear end..I wanted to keep the truck as original as possible, and was steered in this direction after rebuilding the brakes and shimming the bearings / replacing the rear seals.
I would like to thank my friend Joe, a master machinist, welder and fabricator here in Minneapolis, MN.
The truck is a breeze to drive now..it moves along so much easier, and I am able to fully use granny gear.
If others here have an interest in doing this, I will post more of the story. There are many pictures, and many steps we took. It was more expensive than swapping in a bronco or mopar rear end, but I had already went thru the rear axle and decided to try it.
It turned out to be a blessing in disguise, as the rear carrier was found to be cracked and the 4.18 ring and pinion had chipped teeth. The rivets had hit, and the ring gear was loose on the carrier.
Take care, Mike

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Post Mon Aug 26, 2019 12:58 am

Re: 3.54 in a kb2 rear housing...Whaaat?

might be more expensive than most would go, but if you are willing, I am sure that some may like to know the details. Just my thoughts.
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Golden Jubilee
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Post Mon Aug 26, 2019 5:42 am

Re: 3.54 in a kb2 rear housing...Whaaat?

Yes, tell us more. It's always good to know all the options.

Dean
Lifelong Kansan
Grew up with red paint
Moved off the farm 30 years ago.

Golden Jubilee
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Post Mon Aug 26, 2019 10:19 pm

Re: 3.54 in a kb2 rear housing...Whaaat?

I am also interested. There are so many variable in hypoid design, I find it remarkable that one could find parts that will work as intended in another housing. Hypoid offset, pinion bearing placement are two big issues. Then there are easier to measure things like ring gear diameter.
For starters, the pinion offset would have to be identical, and is not something that can be changed, it is a function of how the case is cast and machined.
Pinion bearing placement can be fiddled with a bit, but it would have to be close to where it needs to be to begin with.
Then there is how the ring gear is placed on the carrier. This can require different carriers for large ratio changes. Sometimes it is possible to shim the gear or machine the carrier, but that is no small project.
Considering how highly loaded the pinion is, the case strength where the bearing sit is an issue.
If the hypoid offsets aren't identical there is no way to make them work together with a different offset, the gears are hobb'd for one orientation only.
As the resident proctologist I'm all ears on how this was done.
Looking at the picture, I see a coupla things that concern me, 1st the case looks to be welded, 2nd I see no attaching rivets or bolts holding the ring gear on, how is it attached? 3rd the side bearing lock is not installed correctly to lock the bearing adjuster. Was the picture taken when he was still making adjustments?

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Post Wed Aug 28, 2019 12:08 am

Re: 3.54 in a kb2 rear housing...Whaaat?

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ring gear machined recess for carrier, bolt holes added and fine threads tapped..
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center lathed out..
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34 ford rear.. back from annealing to be machined..


First I bought a high speed rear for a 34 Ford from Little Dearborn..cost was about $500. We chose this for two reasons.. the ring has enough material in the center to allow us to machine it out, and the pinion has a ''bull nose'' on it to allow for chucking into the lathe...we than had it annealed so that it could be machined..

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Post Wed Aug 28, 2019 12:23 am

Re: 3.54 in a kb2 rear housing...Whaaat?

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new ring gear safety wired bolts on to the carrier...also a ford rear bolt kit.. we had to shorten them and drill the wire holes...
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back of the carrier also machined to allow for a larger diameter pinion...it was welded..the crack we found was old and had been in there many years..I wanted another carrier, but this one magnafluxed ok, so I went with it...

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Post Wed Aug 28, 2019 12:53 am

Re: 3.54 in a kb2 rear housing...Whaaat?

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now people are really going to yell.. we welded on the newly threaded gear to the old shaft.. it was true to within 1000th. Mind you, everything was pre-heated before welding, and cooled down slowly over 24 hours..there are more welds on the other side, which fit into a recessed collar the gear rides on ( it has to stick up further in the rear housing...this was all re-hardened, all magnafluxed and certified, and we had it cryo-treated to relieve internal stresses..IF ...and I say IF it ever failed, it would have to fail in reverse, as the threads are ''tightening'' it onto the shaft as you move forward.. I suppose if you absolutely dumped the clutch in reverse, with a full load up hill, you could crack the welds in theory and it would spin off..after the meteor hits..
20190623_153842.gif
..this is the old international pinion shaft..we machined the gear off and threaded it to accept the new cut off gear for the 34 ford...
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Here's where people might start pitching a fit.. we are cutting the gear off the 34 ford pinion shaft... bear with me...

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Post Wed Aug 28, 2019 1:24 am

Re: 3.54 in a kb2 rear housing...Whaaat?

20190825_165321.gif
beginning to establish the pattern.. note the pinion has to rise up from the bearing (on a collar) because of the decreased diameter of the ring gear...we used LEAD paint! ...(that's whats wrong with me...)
20190825_154857.gif
...the bolts stuck up a bit more than the rivets did.. we had to make more clearance in the housing..removed about 1/16 inch on the plane of rotation...this had been scored before we even started when the old teeth had chipped off... ( I drove it unknowingly that way for two years..)

Golden Jubilee
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Post Wed Aug 28, 2019 8:37 am

Re: 3.54 in a kb2 rear housing...Whaaat?

Fantastic. I understand and respect what you did.
I would rather have tools I do not need than to need tools I do not have
“Never argue with stupid people, they will drag you down to their level and then beat you with experience.
Mark Twain

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Post Wed Aug 28, 2019 10:41 am

Re: 3.54 in a kb2 rear housing...Whaaat?

Lots of intensive work there. With the little that I learned in School, I have great respect for the work put in.
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