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Dauntless Drivetrain Change

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    Posted: 01 Nov. 2017 at 10:11pm
In the late 80's I took possession of a '46 2A.         It had a 225 V6 when I got it.     The rest of drivetrain was stock.     It needed a lot of work, but I was so thrilled to have it.

In the first couple years (after a couple Jeep Jamborees) it got 11" brakes, and a rear Lockrite (the first year they offered a 10-spline).   

A few years later the stock spindle pulled loose on a trail ride. (imagine your front wheel laying flat on the trail, haha)   Rather than fix that,    I replaced the whole axle with a Dana 30 from a '74 CJ-5.

It has been basically the same for 20+ years, except for a Herm OD a few years ago.

Some recent threads on '2A page (great trails, and Dauntless related)
have got me thinking about finally doing some upgrades.

Bucket list, one or more of these:
- CFCT
- Rubicon
- Ouray

Not sure I can pull off the distance those require, but would love for my '2A to be ready if the opportunity comes up.

Plus, I am getting old enough now that if I don't do soon, I may not want to fool with it later. haha


Edit:

For those coming into this thread for the first time,  here is a spoiler on where the build ended up.   
If still interested,  you can continue reading the twists and turns the design took over the next few months.  LOL

This was a sheet I put on Wilson at the Willys reunion in Aurora,  May '18




Edited by JeepFever - 20 May 2019 at 12:58pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov. 2017 at 10:22pm
I am not planning the "ultimate" but rather build the best I can with the parts I have gathered over the years. (very cheap or free, :-) )

My nature is to spend as little money as possible, and do as much work as possible on my own. :-)

Gathered so far:
- Low mileage 225 Dauntless
- GM bellhousing
- a couple decent SM420 transmissions
- a couple decent Dana 300 transfer cases
- mid 70's Dana 44 flanged axle rear
- mid 70's Dana 30 front (already installed)

I will need to purchase SM420 to Dana 300 adapter for sure.

I am sure this conversion has been done before, but have not found any examples yet.   What pitfalls are ahead? I am wondering mainly about the rear driveshaft.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov. 2017 at 10:49pm
Other issues I am looking for input -> is the gear ratios.

Currently stock:
Low range = 37:1 (2.79 x 2.46 x 5.38)
RPM @ 55 = 2250 with OD

This new setup with the stock 3.73 gears, in the replacement axles I have, would be
Low range = 69:1
RPM @ 55 = 2079

How happy would my '46 be with 69:1 on my bucket list?
(keep in mind that the 225 seems to have great low end torque, and heavy flywheel. :-) )
.
Edit:  made corrections to T-90 1st ratio, plus found out later the axles have 3.73 not 3.54

Edited by JeepFever - 29 Jan. 2018 at 11:48pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 7:12am
Originally posted by JeepFever JeepFever wrote:

....I will need to purchase SM420 to Dana 300 adapter for sure.
  I thought you already had one?

This is the reason I went with an SM465.  The reverse bulge is on the opposite side of the front drive shaft so the tranny/adaper/TC length is much shorter.  I paid $250 for my last 465 so to me, that money is worth the lack of aggravation. (IMO mileage may vary)  
Quote
This new setup with the stock 3.54 gears would be
Low range = 65:1
RPM @ 55 = 1970

I would rethink the 3.54 gears mainly because of the carrier breaks.  The carrier break on a D44 30 spline flanged axle is 3.73 or numerically lower.  This is not a huge problem because you can buy a thick gear and get to higher numeric ratios but the carrier break on a D30 is 3.54 and numerically lower so you are locked into 3.53 unless you change carriers.  You did not talk about a front locker but if one is going to be part of this upgrade, you will have some decisions to make.  I seriously doubt you would ever want to go numerically lower than 3.54 but I could see you wanting to go numerically higher.

(Opinion only)
I would at a minimum go with 3.73 and based on my small experience, I'd better consider 4.11.  This way you can buy a locker/carrier for you D44 that uses the normal ring gear with options should you change your mind in the future.  65:1 is way better than stock but I wouldn't call it great, especially when your top end is overkill.  I don't know the dauntless motor but a quick google search tells me that that it produces maximum torque at 2400 rpm.  Going off your numbers, that would be 67 mph.  unless you are planning on cruising 67 regularly, I would take some of your top end and donate it to the low end.  65:1 is low but I'm not sure it's low enough to just take you foot off the pedal and walk up anything.  Again, just an opinion.

Edit:  you can’t buy a thick gear for a D30 that I know of. Maybe someone else knows something I don’t. 


Edited by jpet - 02 Nov. 2017 at 7:38am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 10:55am
You needing a Dauntless flywheel ?

Time proven standard crawl ratio for Jeep CJ  is 37/1 crawl ratio not 39/1.


I agree with Jeff that the frustration of a SM420 installation can be huge.
You'll run into front propeller shaft issues and besides the SM 420 is a very sloppy shifter. 
The SM420 shift lever is all over the place. 
Especially true if the tower is  worn.

The Dana 300 provides  a nice reduction ratio @ 2.62. but not quite good as the TL 3.15. 
Is this the common round pattern or the rare IH Texas pattern ?

Only the 1972-1975 CJ's were equipped with narrow track center flanged Dana  44's. 
These are some of the best Jeep axles of all time....
The D44 centered axles work very well with Dana 30 and Dana 300 transfer cases.
The standard  for 1972-1975 FDR was 3.73 with an optional ratio of 4.27.

1976 -1981 narrow tracks Jeeps have AMC  centered carrier and two piece axle shafts.
3.54 became the CJ standard beginning in 1976 
Shy away from these AMC axles. 
They are no good unless the two piece shafts are upgraded.

Quote  The carrier break on a D44 30 spline flanged axle is 3.73 or numerically lower.
Technically it's the case and not the carrier. 
The "carrier section" is the  cast steel housing porting of the axle assembly (AKA  pumkin)
The "differential case break" for Dana 44 is between 3.92 and 3.73. 

3.54 differential ratio is good for a CJ that sees limited off-road useage
3.73 differential ratio is near ideal for a jeep that sees lots of both uses.
Dana with 3.92 is also available as a GM ratio.
These ratios can work well for Jeeps without O.D. capability.

5,38 and 4.88 work well for Jeeps seeing ample off road use.
These slow ratios are best on-road when equipped with O.D. units.

4.10, 4.27 and 4.56  are compromise ratios and these ratios generally are not over driven because the compounded ratio is considered as too fast for Jeeps
Dana 4.56 is an IH ratio not Jeep.

One does not need the ultimate jeep to run obstacles but they should definately prioritize what important.  
Something like this....
1) Tire height, and underneath clearance.
2) Slow gearing.
3) Traction devices
4) Suspension flex


Edited by oldtime - 02 Nov. 2017 at 11:14am
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Post Options Post Options   Thanks (1) Thanks(1)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 11:31am
 
Originally posted by oldtime oldtime wrote:

..Technically it's the case and not the carrier. 
The "carrier section" is the  cast steel housing porting of the axle assembly (AKA  pumkin)...

Technically a pumpkin is a round orange type of squash suitable for making pies.  I only call it the "carrier" because that's what most of us call the assembly.  Same reason I call "U" shackles "C" shackles. and tissues, kleenex. 


Edited by jpet - 02 Nov. 2017 at 11:33am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 11:51am
Thanks Jeff and Ken . .  two guys I was hoping would weigh in.  :-)    I will read this more carefully this evening.  

A couple quick notes.   
1) I have been storing these SM420's for years,  it is really going to pain me not to use one of them.  haha   Sure sounds like I need to reconsider though.
2) I thought the existing gears my '72-75 axles were 3.54, I am encouraged to hear that I must be remembering wrong. . .  3.73 puts me at what I am guessing would be my ideal for the on-road uses. (a little bit taller than current 5:38 +OD)     It drops the low close to 69:1,  (but of course if I go with SM465, that will go back closer to 64:1)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 11:59am
Originally posted by jpet jpet wrote:

Originally posted by JeepFever JeepFever wrote:

....I will need to purchase SM420 to Dana 300 adapter for sure.
  I thought you already had one?
I had a feeling back then that I would not be able to keep the project moving forward,  so I passed it on to someone who was very interested in continuing with the development.
Proof that I did not have the time ->  I have not made any progress on my '3A or this one since then :-(
Unfortunately I have not seen any posts from him either. :-(
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 2:20pm
Originally posted by JeepFever JeepFever wrote:

. .  3.73 puts me at what I am guessing would be my ideal for the on-road uses. ...
IMO, the main advantage of 3.73 on the road is for road noise.  As you know, I ran 3.73s for 3 years on lots of hi-way.  60 is easy.  65-70 is easy but can wear you out if its windy.  I've even done 80 with pedal to spare.  Recently, I changed gears because even though, I can cruise, I always found myself running 45-50 anyway and maybe 55 when I'm in a hurry.  Usually, I only do 70 when I'm showing off Embarrassed 

If you go to 4:11, you would be doing 2287 rpm @ 55mph which is closer to your power band and still a low rpm, and your basement now becomes 75:1 or with a SM 465 69:1 ..... not bad IMO  I went to 4.56 but I may change out to 4.27.  The jury is still out for deliberations.

.... this is in the case that you have to buy new gears anyway.  If you find out that you do in fact already have 3.73s, I would just put them in and find out for myself rather than going on someone's else's experience.  You don't have to make a decision till you experience for yourself or you decide on a front locker but hopefully you do have 3.73s because then, at least you have options as described in previous posts. 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 6:19pm
So Jeff you got me to wondering .... did they ever decide if a big ole ....
PUMPKIN is a fruit or  is it a vegetable ?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 7:01pm
that’s ok Ken. When you said pumpkin, I knew you really meant  hog’s head
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov. 2017 at 11:20pm
Today's thoughts on build strategy, (Ironically, today showed the most common use of my '2A):

1)off-road: A neighbor of my son had some storm-damage firewood. The path down to the wood was carved out by a bobcat, and was very narrow. It would have been so much easier to weave the '2A and Bantam trailer thru the trail, if I could have gone slower. 65:1 = win   (5 trips down and back to son's house)

2)on-road: Getting to my son's house from ours has a stretch of maybe 5 miles on 4-lane 60 mph speed limit (that most cars are going 65+) I don't try to keep up with traffic, but more like 55-60. The engine seems to spin too fast, and I wish the '2A had another gear. 3.73 = win (over my current setup 5.38x.75=4.03) The '2A can very easily pull a long hill at one point, even with trailer. A taller gear would not be an issue, I am guessing.

Oh . . checked the D44 . . could not read the tag, so popped the cover. tooth count 41/11 = 3.727!!!

Now I need to find the 3.73 set for D30 . . the ones I have been saving, (that I thought came from this axle) are 46/13=3.538 (the reason I thought both axles were 3.54)



Edited by JeepFever - 02 Nov. 2017 at 11:35pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 6:56am
Originally posted by JeepFever JeepFever wrote:

....Now I need to find the 3.73 set for D30 . . the ones I have been saving, (that I thought came from this axle) are 46/13=3.538 (the reason I thought both axles were 3.54)
I have my original setup and I will donate them to the project if you PM me your mailing addy.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 10:33am

That's very similar to the way I frequently use my mine.

Jeeps are excellent for extracting small and medium loads of firewood out from tight restricted areas.

Until now I have done very well using a strong running 3B in stock optional condition. 
I always add front and rear Powr Loks, Warn 25% O.D. and a few other options.
Otherwise standard and  Hurricane powered.
With recent Hi-way driving trends I am now forced to abandon the Hurricane engine that I so dearly love in favor of the Dauntless.
I find the standard 37/1 crawl ratio to be very marginal when on rough, narrow and heavily wooded tracks.

You really need to envision your build as a COMPLETE SYNCHRONOUS SYSTEM of complimentary assemblies.

You have an O.D. unit yet you are considering installing 3.73 FDR.
Going to 3.73 FDR is O.K. but only if you plan to eliminate the O.D. unit.

Like I said 3.54 , 3.73 and 3.92 (GM ratio) are only good for jeeps that do not use O.D. unit.
So they only work well with Dana 20 and Dana 300 units.
Those ratios allow you to cruise the hi-way at sensible crankshaft velocity.

IF one runs 3.54 3.73 or 3.92 then they MUST install a wide ratio transmission if they expect to have any kind of crawling ability slower than "time proven standard crawl ratio" of 37/1.
In other words the best one can practically do with those differential ratios and is typical 37/1 crawl ratio.
Example:3.92  GM Ring Pinion 3.16 Tera Low Dana 20 2.99 Borg Warner T15 =  37/1 CR.

So going to 3.73 basically mandates installation of a Wide Ratio (WR) 4 speed if you need low CR.
Your choices are T98, T18, SM 420, SM 465, and New Process 435.

Your transmission selection is influenced via the transfer case selection.
Are you set on the Dana 300 ? 
Is it the rare 1980 IH Texas pattern or the round Jeep input pattern ?

Think "synchronous system" before you finalize your differential ratio.





Edited by oldtime - 05 Nov. 2017 at 4:03pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 11:13am
Originally posted by jpet jpet wrote:

Originally posted by JeepFever JeepFever wrote:

....Now I need to find the 3.73 set for D30 . . the ones I have been saving, (that I thought came from this axle) are 46/13=3.538 (the reason I thought both axles were 3.54)
I have my original setup and I will donate them to the project if you PM me your mailing addy.

Wow, very generous!!  Smile

I will look around some more first.   It is baffling where the 3.54 set came from,  if not this axle,  they are in the original packaging from the 5.38 set I bought a long time ago,  when I put this axle in the '2A

 -Ron
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 11:48am
Originally posted by oldtime oldtime wrote:

. . .   You really need to envision your build as a COMPLETE SYNCHRONOUS SYSTEM of complimentary assemblies.   . . . 


My plan all along has been for wide ratio 4-speed with the flanged axle D44.  I have both D20 and D300 xfer cases,  but did not plan to re-gear them,  so am thinking the D300 because of better stock ratio.   Both of my D300's are the round ones from mid '80's CJ-7s

Originally posted by oldtime oldtime wrote:

You have an O.D. unit yet you are considering installing 3.73 FDR.
Going to 3.73 FDR is O.K. but only if you plan to eliminate the O.D. unit.

I plan to use the OD on '51 '3A project, 5.38 . . .  if I ever get moving on it.  

My dilemma is too many projects and not enough time.   I really wanted to finish the '51,  complete with OD and PTO for running the wood-splitter,   THEN start on this trail/work '2A rebuild.     But I keep drooling over the Colorado runs,  and think I want to be ready if by some wild chance I get the time off from work one summer/fall to go out there.   

My current plan -> split up as much firewood as I can find,  using the '2A,   then tear into it this winter.  I will really miss not having a running Jeep,  but maybe I can get this done fairly quickly if I concentrate on it.      (Hey just thought of something,  maybe my son would want to park his CJ-7 in my driveway to get it out of his way,  he does not drive it much,  haha)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 11:53am
Originally posted by oldtime oldtime wrote:

You needing a Dauntless flywheel ?

Time proven standard crawl ratio for Jeep CJ  is 37/1 crawl ratio not 39/1.


I don't need a flywheel as far as I know.   The "new" engine already has a decent looking one on it

I was going on memory when I was calculating that (the reason for question marks,  haha)



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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpet Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov. 2017 at 12:10pm
Originally posted by JeepFever JeepFever wrote:

.....My dilemma is too many projects and not enough time.  ....
Not to be critical, just a yokel observation, The parts you have collected and are working with would be for a person who has lots of time, but not much money.

If you have a little money, but not enough time, the best thing is to find someone else's unfinished project and start from there.  In the end, you save money because you get  lot of new parts at a discount, and you save time because lots of the engineering, labor, and parts collecting, are already complete.  You do have to come up with the initial investment.

If you are strapped for cash but have the time, you can figure out how to mate a Dauntless to SM420 to a round D300 and fit it all into an 80" wheelbase vehicle.  You may save a few bucks but you might have your work cut out for you.

If you have neither time, nor the money ..... well, ......just have to comb the adds and have lots of patience.
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