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Blackdiamond72
01-14-2010, 04:10 PM
So I've never owned a 3sp 40 before and I'm finding my new one to be a real dog. Its on 33"s with a 2f and original driveline behind it. Going up hill near my house in high is near impossible above 30mph. My 78 wasn't a champ either but it did much better than the 69.

My questions are:

1. Does the 69 have 4.11's in the diffs? Is it worth it to go to 4.88's (cost vs performance)?

2. I'm planning on going to a h41 4sp later this year, I know that 4th is still 1:1 so no improvement there but will 3rd be close to a split between 2nd and 3rd in a 3sp tranny?

3. Quite a bit of people on mud swear by the sm420 or sm465, should I be looking that route?

4. Also, I know that the gearing in the 3sp transfer is lower than the 4sp transfer in low range, worth swapping the gearing from the 3 to 4sp case?

Any opinions would be great as I'd like to start collecting parts. Thanks!

James

FJBRADY
01-14-2010, 04:16 PM
3. Quite a bit of people on mud swear by the sm420 or sm465, should I be looking that route?



I have the sm420 in my 40. It acts like a 3 speed since 1st gear is 7:1 so it's useless on the street. I have 4:11's and 36 inch tires but instead of the 2F I have the 350F so I can't comment on the stock set up, but I am sure someone here will.

Blackdiamond72
01-14-2010, 04:24 PM
What I found depressing is I called Merl at Classic Cruisers and he told me to put in a LS1. When I informed him that wasn't an option, he said to beef up my motor the best I can. Hmm

corsair23
01-14-2010, 05:34 PM
I have a stock 2F in my 40, with stock gearing I believe (did the spin test and math came out around 4.11 :hill:), and a SM420

I'll ditto what Steve says about 1st gear in the SM420 and it being useless on the street...I think at max rpm I'm going maybe 10mph max.

My thoughts after owning a '76 with the stock 4spd and now the '74 with the SM420. The stock 4spd was a MUCH better street transmission. The gap between 1st and 2nd in the SM420 is huge and for all pratical purposes you have to start out in 2nd gear with the SM420 which puts additional wear/stress on the clutch IMO. That was the main reason I dropped down from 35s to 33s on my 40 shortly after buying it. With 35s, starting out in 2nd gear, you could just tell the clutch was crying in pain.

After all the great things I had read about the SM420 and SM465 I thought I really wanted one in my 40 and when I found a 40 with one in it that was a selling point to me. Now...well I love the SM420 for offroad crawling/control but 99% of the time I dislike the SM420 for its street manners. It is loud, clunky, shifts poorly etc.

I think if I had my choice and $$ were no object I would go with the Toyota 5spd (H55?), change the gearing in my diffs (4.56 if avail, not sure, or 4.88s) and see how I like it. If offroad capability takes a hit then I'd look into different t-case gearing or adding an Atlas or something.

At one time I thought I really wanted an NV4500 5spd but from what I hear there are downfalls with that tranny as well...

You're not exactly next door but if you ever want to come down and take the 40 for a spin to see what you think just let me know :thumb:

nuclearlemon
01-14-2010, 05:54 PM
yes, you've got the 4.11 gears, and i wouldn't bother with an sm420/465. i had them and they aren't great. they are geared a bit lower for better crawlability, but they are a clunky truck tranny. swap in a cruiser 4spd and cam your motor. also send your carb to someone like jim c...he can do wonders. adjust your valves and give it a great tuneup, then remember you're not driving a sports car

FJBRADY
01-14-2010, 05:57 PM
and i wouldn't bother with an sm420/465. i had them and they aren't great. they are geared a bit lower for better crawlability, but they are a clunky truck tranny.

Hey, hey now I resemble that comment!

Air Randy
01-14-2010, 08:49 PM
I have the H41 4 speed in my 40. It is a MUCH better option than an SM420. It has a 5-1 first gear versus stock H42 3.5-1 1st gear so you get lower gearing for off road but still very driveable on the street. Plus being it's a stock Toyota tranny it bolts straight in with no adaptors and will shift exactly like your H42. The only drawback is you usually have to pay about $600 for one in good shape. You can get them from MAF and Mark's Offroad plus several other places.

2nd and 3rd gear are also slightly lower ratios than the same gears in an H42 and 3rd is a nice split between 2nd & 4th. I think if your 2F is running good and with the H41 you would be real happy.

The aussies got the H41 so they could drive the outback roads in high range but their first gear was low enough to get them through a rough stream crossing or something similar without shifting into low range.

wesintl
01-14-2010, 09:11 PM
problem is the gap between 2'nd and 3rd with a 3 speed. The 4 speed will allow you to 1.4 3rd vs 1.7 2'd 3 speed. Is it flogged in 2'nd at 30? Course the 33's don't help uphill.

If you did any changes I think the best bang for the $ is a h42

Blackdiamond72
01-14-2010, 09:47 PM
I was leaning towards the h42 to begin with as they are cheap, plentiful and proven. I just figured why not ask to see what others thought on the subject. Correct me if I'm wrong, but all you need to do a 4sp conversion is the h42 bellhousing, new drivelines, and a adaptor for the 10 spline output. I figured I might as well get the 4sp transfer with the tranny to simplify things.

I would eventually like to go to 35s, so maybe changing the 3rds to 4.88 would be in order as well down the road.

Thanks corsair for the offer, I might have to take you up on that to confirm my feeling about the sm420. Are you going on Saturday?

corsair23
01-14-2010, 10:10 PM
Thanks corsair for the offer, I might have to take you up on that to confirm my feeling about the sm420. Are you going on Saturday?

Unfortunately I'm not going Saturday :( - Although taking the 40 on the snow run does sound fun :) - offer stands though if you ever find yourself down this way.

Rzeppa
01-15-2010, 10:16 PM
So I've never owned a 3sp 40 before and I'm finding my new one to be a real dog.

I drove my 71 on and off road for many years before I swapped an H42 into it. I loved the 3 on the tree but the 1st ratio was interesting off road and made me a better driver. As far as engine performance, carb and ignition timing are the real keys to get up and go. The old F is actually pretty peppy when set up right. 2X on the 2F.

Its on 33"s with a 2f and original driveline behind it. Going up hill near my house in high is near impossible above 30mph. My 78 wasn't a champ either but it did much better than the 69. Again, carb and ignition timing are really key.

My questions are:

1. Does the 69 have 4.11's in the diffs? Is it worth it to go to 4.88's (cost vs performance)? In order, yes, and no

2. I'm planning on going to a h41 4sp later this year, I know that 4th is still 1:1 so no improvement there but will 3rd be close to a split between 2nd and 3rd in a 3sp tranny? I have an H41 in my 76 and had an H55F in my HZJ75 with pretty much same ratios. WAY better than SM420/SM465/NV4500 as far as shifting smoothness, and as others have mentioned, the SMs are basically 3 speeds for everything but off road, 1st is granny gear and you really don't want to start out in it on road. The H55F and NV4500 are too long for a 40 because your rear DS becomes way too short unless you're lifted like crazy and you've built a buggy IMHO.

3. Quite a bit of people on mud swear by the sm420 or sm465, should I be looking that route? See above

4. Also, I know that the gearing in the 3sp transfer is lower than the 4sp transfer in low range, worth swapping the gearing from the 3 to 4sp case? Yes

When I swapped my H42 into my 71 using my 3 speed t-case I ran into a bunch of gotchas that you won't see on mud, but I wrote them up here.

Happy cruisin'!

Shark Bait
01-16-2010, 12:10 AM
4. Also, I know that the gearing in the 3sp transfer is lower than the 4sp transfer in low range, worth swapping the gearing from the 3 to 4sp case?



The swap to an SM420 will be very easy for you. You already have the bell housing you need. So you'd need an adapter plate and the conversion gear.

If you go with the H42, which is a nice street transmission, you'll need the later bell housing & clutch fork and the t-case shifter linkage.

Your drive shaft lengths will change with the swap, but the good news is a stock rear 4-speed drive shaft will work with either tranny.

BTW, I have a 4-speed t-case shell you are welcome to.

Rock Dog
01-16-2010, 12:20 AM
I have the 3 spd gears in a 4spd case and it does help.. the $spd case is stronger (gusseted), and not a brittle as the 3spd case.
I also have an Aussie tranny that i got from Manafre years ago.... at something like a 5:1 first it is more usable than the SM465/SM420 on the road. (for that matter i also have a Rock Box i never installed.. lol) ...

Rzeppa
01-17-2010, 01:50 PM
If you go with the H42, which is a nice street transmission, you'll need the later bell housing & clutch fork and the t-case shifter linkage.

Your drive shaft lengths will change with the swap, but the good news is a stock rear 4-speed drive shaft will work with either tranny.

I used the 3-speed flywheel and clutch when I swapped the H42 into my 71 with 3-speed t-case. That way I got the heavier flywheel and didn't have to re-route the hydraulics as the slave stays on the same side. The 4-speed bellhousing is a must as the H42 doesn't mate to the 3 speed bellhousing.

4 speed driveshafts will not bolt right up. While they are the correct length, the yokes won't fit the 3-speed t-case companion flanges. I had my 71 driveshafts retubed at Englewood Driveshaft.

Blackdiamond72
01-19-2010, 01:15 PM
Wow, thanks for all the insight guys.

After discussing this issue with my neighbor quite a bit, I'm starting to lean towards an auto. A a440f preferably. To gain the extra length required for the longer tranny, I'll do a 4 link rear with custom control arms and old tj springs.

I do really like the idea of a h55f, however if I get more into the crawling scene an auto would be nice. Also, the torque multiplication would help if I stay with 4.11. Thoughts?

Could I mate a 4sp transfer to the a440f? I would like to keep my pto.

Rzeppa
01-19-2010, 09:38 PM
HI James,

I strongly recommend against anything that decreases the rear driveline length for an FJ40, which includes Toyboxes, NV 4500s and H55Fs. Autos generally also increase that length, no matter which adapter unless done with a V8 swap at the same time.

When talking about going (fill in the blank) link IRS, all bets are off and now you are talking about a much huger scope of modification, and mating a 4 speed t-case to an A440F while retaining your PTO is a much smaller part of a huge project.

Best of luck and happy cruisin'!

Blackdiamond72
01-20-2010, 02:00 PM
Thanks for grounding me there. I am sick of the 3sp and was at first looking for a fix that would make me happy for the time being without spending $$$ to get there before moab, however I began to dream a bit. Still not sure if I'll change out the trans before late april. Not sure if I'll make it anyways, too many issues to fix before then.

Thank you all for your input though, much appreciated!

James

subzali
01-20-2010, 04:37 PM
If you're trying to make it to Moab I would suggest just getting an H42 and being done with it. There's enough modification needed as is that will take some time and extra $$ to get there. Unless your work schedule isn't heavily loaded and you can spend a lot of time to get everything done. Lots of people have done many of Moab's tougher trails with a manual tranny...

just my :twocents: