why not a dana 18

Discussion in '40- & 55-Series Tech' started by thewatergoblin, Jul 27, 2005.

  1. thewatergoblin

    thewatergoblin

    Messages:
    196
    Likes Received:
    3
    Joined:
    Jun 28, 2005
    Location:
    NE, Arkansas
    got a question for all you guru's. Why is everyone doing conversions with a sm465 or a sm420 and the toyota transfer case? On my cruiser the option I took was a 465 and a dana 18. I studied everything and felt the advantages of a dana 18 far out weighed the advantages of the stock t-case. With the 18 you have twin sticks, already mounted on a case bracket on the t-case, so you dont have to cobble or build linkage. You also have the option, that i took, just plug in a warn or saturn overdrive. If you want to keep your rear drum parking brake, thats no problem either cause the majority of the 18's had the parking brake. Theres alot of modification to use the stock t-case especially using a sm420. I was just curious, is there some advantages I have missed, or something im confused about. Let me know. :cheers:
     
  2. Tigerstripe40

    Tigerstripe40

    Messages:
    2,234
    Media:
    1
    Likes Received:
    147
    Joined:
    May 3, 2004
    Location:
    Utardia

    I run an SM420 with a '4 speed' t-case, and found the modification necessary to run it minimal, and for the most part it was a bolt in ordeal.

    No driveline mod's.
    No skid plate mod's
    No Tranny tunnel mods.

    What mods ar eyou talking about?
     
  3. thewatergoblin

    thewatergoblin

    Messages:
    196
    Likes Received:
    3
    Joined:
    Jun 28, 2005
    Location:
    NE, Arkansas
    from what i hear you have to drill the output shaft on the 420, tap it and then make a retaining nut to hold all of it together. Also, did you have to grind the case on the 420 to get clearance for the front driveshaft. and what about making brackets for the t-case shifters. did you have any of these problems?
     
  4. e rock

    e rock

    Messages:
    1,622
    Likes Received:
    14
    Joined:
    Feb 24, 2004
    Location:
    Monroe, WA
    :confused: My tcase isn't modified at all. I took out an extra support bearing, but that isn't even necessary.


    Nope. I swapped in a 420 in place of a 3speed, so my experience was a bit different than Tigerstripe's.

    The sm420's output shaft is already tapped. There is a retainer setup that most people use to keep the bolt from backing out, but it's not anything complicated at all.

    I used an EBI adapter plate which clocks the tcase down a few degrees so no grinding required. Other plates which don't reorient the case are usually ok with just grinding down some extra metal on the driveshaft yoke.

    My tcase shifter mods involved threading in some 1/8" npt air line fittings and using some 3/8" air hose I had laying around to extend the vacuum lines. Also, I had to cut & extend the low-range shifter rod with some 1/2" steel tube - tack welded at the ends.

    I did have to get some driveline shortening and lengthening done, but unlike a D18, I was able to keep my stock flanges and everything still lines up right. I was also able to keep the stock dash lever and vacuum switching capability.

    I just don't see ANY advantage to a D18.
     
  5. Tigerstripe40

    Tigerstripe40

    Messages:
    2,234
    Media:
    1
    Likes Received:
    147
    Joined:
    May 3, 2004
    Location:
    Utardia
    I used a plate style adapter.

    Another option is the long Advanced Adapters style adapter, which requires expensive driveshaft (lengthening, shortening, balancing, etc) modifications.

    IIRC the Dana 18 T-case ALSO uses the long style adapter to adapt to the SM420 , so expensive driveshaft mod's are also required.

    The SM420's output shaft is already drilled and tapped, as the SM420 was only used in 2WD applications, and the output yoke was bolted directly to the shaft.

    As far as grinding the SM420 case, I talked to Tourist transmission in salt lake city about the grinding. They said that the case in that area is REALLY thick, and overbuilt. You could grind it to 1/32" thickness and not have any strength problems with the case.

    Twin Sticks -Honestly, I don't see an advantage to twin sticks, neither the Dana 18 NOR the cruiser case have a front dig only option.

    Plate for the shifter: not a problem. Part of the conversion processo. Once you get the plate made and adjusted properly, it all fits under the tranny tunnel, and looks like it's supposed to be there.
     
  6. G_Stratton

    G_Stratton

    Messages:
    191
    Likes Received:
    2
    Joined:
    Feb 17, 2004
    Location:
    Sedro Woolley WA
    When I bought my SM420 it was already adapted to a Dana18. I have had no problems with this setup.

    The adapter between the trany and t-case is about 4 1/2" long.

    I felt it was worth putting in as I got the whole thing for $200.

    I believe the crawl ratio works out to 71 to 1.

    I did have to get new drivelines made, but I was going to have that done anyways because I flipped my springs to stretch the wheelbase.

    Guy
     
  7. jcj_78FJ40

    jcj_78FJ40

    Messages:
    1,148
    Likes Received:
    239
    Joined:
    Apr 7, 2005
    Location:
    Afton VA
     
  8. Tigerstripe40

    Tigerstripe40

    Messages:
    2,234
    Media:
    1
    Likes Received:
    147
    Joined:
    May 3, 2004
    Location:
    Utardia
    I got a new T-case input gear from Cruiser Outfitters. 10 spline internal splines, and the correct outer gear tooth count for the 4 speed t-case, and it's MUCH quieter than the '3 speed' t-case

    It was ~$80
     
  9. thewatergoblin

    thewatergoblin

    Messages:
    196
    Likes Received:
    3
    Joined:
    Jun 28, 2005
    Location:
    NE, Arkansas
    ok, thanks for the info, where do you get the plate to clock the t case? Ok, you cant argue with this one though, OVERDRIVE.
     
  10. thewatergoblin

    thewatergoblin

    Messages:
    196
    Likes Received:
    3
    Joined:
    Jun 28, 2005
    Location:
    NE, Arkansas
    ok, thanks for the info, where do you get the plate to clock the t case? Ok, you cant argue with this one though, OVERDRIVE. No landcruiser case has the option of a bolt in overdrive unit. Especially for the price you can pick up an old warn for. I have to admit though, after reading what you wrote, im considering the lc 3 speed t-case on the one im building now. I just have to think about it. One thing is ive got a couple that are in great shape and already have the advance adapter mounts on it.
     
  11. cruiser ken

    cruiser ken

    Messages:
    647
    Likes Received:
    4
    Joined:
    Jan 15, 2005
    Location:
    Saratoga Springs, UT
    I've heard D18s have a reputation for breaking. I've also heard this is caused in part by not providing a mount for the front nose of the tcase (there's a tab at this location and some people don't use it). I ran a dana 18 with O'brien gears. The case held up fine but the gears grenaded. Went back to stock gears. I've also seen pics of stock gears with the low range teeth gone (I lost high range teeth). I don't think a dana 18 is any worse than a 3 or 4sp cruiser case but I don't see them as significantly better either. Just another option. I ran mine because my cruiser had a 302 and T18 in it with a dana 20 when I got it and I could re-use the dana 20 adapter for the dana 18.
     
  12. bustanutley

    bustanutley

    Messages:
    2,285
    Likes Received:
    4
    Joined:
    Apr 10, 2004
    Location:
    denver
    Also consider tire size, and axle gears. I don’t' know what you are doing for an engin; if you are going to be running a 350 and an overdrive, no problem. However I know my F would have a really hard time pushing around my 40 in overdrive with 37's and 4.11s. I personally plan to stay 4.11 since they are common. I run 35's now and it gets around on the highway pretty good, I think 37s would be the perfect overdrive ;) Maybe you are not going to be running big meats but with the idea of putting in a 420 I have reason to believe that is your plan :D

    my calculations show 2425 rpm for 65 mph with said setup
    and 2800 rpm for 75 mph
     
  13. Tigerstripe40

    Tigerstripe40

    Messages:
    2,234
    Media:
    1
    Likes Received:
    147
    Joined:
    May 3, 2004
    Location:
    Utardia
    There are no t-case clocking plates per say (like there are for the Atlas @ or Dana 300).

    Mike Smythes plates clock the t-case downward a bit so you don't have to grind on th side ot the tranny, you simply turn the front output and yoke for the driveshaft down a bit to get it to fit.

    Clocking the t-case up would cause interferance between the reverse gear hump and the front driveshaft.
     
  14. thewatergoblin

    thewatergoblin

    Messages:
    196
    Likes Received:
    3
    Joined:
    Jun 28, 2005
    Location:
    NE, Arkansas
    on my cruiser I run a 36-14.5-16 swamper, I could get up to a 40 on there but I like running the smaller tire to give the illusion of a taller cruiser, i guess i cheat a little bit. Anyway, engine is a 350, i love the 2f but its just a little weak for the bigger tires. It does good on flat ground, but I do alot of highway driving in the hills and the 350 makes shifting gears a little less. Right now Im running a j30 (i think thats the number) and a 3 speed case. I dont like not having a granny low and I want an overdrive so Im very seriously considering the D18. Already got a 420, extra 3 speed lc t-cases and a dana 18. Got all the junk just dont know how i want to put it together.
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.