tranny tech 403-thats 4 on the tree!

[red66toy]

Sorry for the delay! Gaskets are made and bolts are here. I’ll assemble the kits and they will be available soon.

 

[red66toy]

Hey all! I got my setup working well and I am super happy with it.
If anyone is interested I have a new batch of adapters available for purchase. These were made here in the US by a fellow cruiser owner/machinist. I'll start a classifieds post and you can DM me for info.

 

[wngrog]

Let’s see how you did the hump?

 

[red66toy]

Let’s see how you did the hump?

Working on that now. I just really wanted to drive it first. . I plan to copy what @Skreddy did since it came out so clean.

 

[KennyBob]

This is such a cool mod, but I’m still wondering what the payoff is for going from a 3 speed to a 4 speed with the final ratio being the same. Is it just the difference in the ratios of the other gears in terms of drivability?

 

[ryanwk628]

This is such a cool mod, but I’m still wondering what the payoff is for going from a 3 speed to a 4 speed with the final ratio being the same. Is it just the difference in the ratios of the other gears in terms of drivability?

Im going to upgrade to a 4 speed for the deeper first and synchros

 

[mrboatman]

I just wish I hadn’t sold off all of my column shift stuff

 

[EWheeler]

This is such a cool mod, but I’m still wondering what the payoff is for going from a 3 speed to a 4 speed with the final ratio being the same. Is it just the difference in the ratios of the other gears in terms of drivability?

I've got rubber overdrive on my '70 with the factory 3 speed trans (4.10's & tall skinny 35's). I have one of Chase's kits, and am slowly working through my other life priority list to try and get this 4spd swap onto the list.

The 4 speed will greatly increase drivability with a stock inline 6 IMO. A combination of a tired old F in a vehicle that has the aerodynamics of a house, this thing absolutely hates the 2nd to 3rd gear split of the J30. If I am on any kind of grade, I just cannot accelerate with the RPM drop from 2nd to 3rd. I typically take it up to about 3k in 2nd which is around 43 MPH. Shifting into 3rd drops my rpms to about 1600-1700 with the gear change and loss of speed during the shift.

With the 4speed, I would be at 33mph in 2nd at 3k, 2nd to third shift drops about the same 1200 rpm as the J30, but im going 10mph slower so I dont have as much drag coefficient to overcome to speed up from 33mph in 3rd. Taking it up to 3k rpm in 3rd gets me to 53mph, which is fine for the majority of my tooling around town. A shift into 4th only drops 800 rpm to 2200. Now I still might not be able to accelerate at 2200 rpm in 4th, but I gained 10mph by being able to stay in the 3rd gear of the H42. Once I hit a downhill, I can shift into 4th

Toyota J30 Toyota H42 Tire Diameter 1st 2.757 1st 3.555 34 2nd 1.691 2nd 2.292 3rd 1 3rd 1.41 4th 1 4.1 Current Setup - 3sp, 4.10 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 1st 8.95 9.84 10.74 11.63 12.53 13.42 14.32 15.21 16.11 17.00 17.90 18.79 19.69 20.58 21.48 22.37 23.27 24.16 25.06 25.95 26.85 27.74 28.63 29.53 30.42 31.32 32.21 33.11 34.00 34.90 2nd 14.59 16.05 17.51 18.97 20.43 21.88 23.34 24.80 26.26 27.72 29.18 30.64 32.10 33.56 35.01 36.47 37.93 39.39 40.85 42.31 43.77 45.23 46.69 48.15 49.60 51.06 52.52 53.98 55.44 56.90 3rd 24.67 27.14 29.60 32.07 34.54 37.01 39.47 41.94 44.41 46.87 49.34 51.81 54.28 56.74 59.21 61.68 64.14 66.61 69.08 71.54 74.01 76.48 78.95 81.41 83.88 86.35 88.81 91.28 93.75 96.22 Proposed Setup - 4spd, 4.10 4.10 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 1st 6.94 7.63 8.33 9.02 9.72 10.41 11.10 11.80 12.49 13.19 13.88 14.57 15.27 15.96 16.66 17.35 18.04 18.74 19.43 20.13 20.82 21.51 22.21 22.90 23.60 24.29 24.98 25.68 26.37 27.06 2nd 10.76 11.84 12.92 13.99 15.07 16.15 17.22 18.30 19.37 20.45 21.53 22.60 23.68 24.76 25.83 26.91 27.99 29.06 30.14 31.22 32.29 33.37 34.44 35.52 36.60 37.67 38.75 39.83 40.90 41.98 3rd 17.50 19.25 21.00 22.75 24.50 26.25 28.00 29.74 31.49 33.24 34.99 36.74 38.49 40.24 41.99 43.74 45.49 47.24 48.99 50.74 52.49 54.24 55.99 57.74 59.49 61.24 62.99 64.74 66.49 68.24 4th 24.67 27.14 29.60 32.07 34.54 37.01 39.47 41.94 44.41 46.87 49.34 51.81 54.28 56.74 59.21 61.68 64.14 66.61 69.08 71.54 74.01 76.48 78.95 81.41 83.88 86.35 88.81 91.28 93.75 96.22

 

[65swb45]

Somebody paste this into the FAQ!

 

[KennyBob]

No kidding! Above and beyond information. Thanks @EWheeler!

 

[EWheeler]

Somebody paste this into the FAQ!

Thanks Mark. I have a nice spreadsheet, but not sure best way to share it. Considered a google sheets document, but I am concerned that would give access to my other personal files on my google drive.

Toyota J30		Toyota H42		Toyota H55f	Ratios	Effective H55 w/ 4:1 split case low gears & 1.1 high	NV4500		T-Case Low Gear Options
1st	2.757	1st	3.555	1st	4.843	5.33	5.61		3spd Low	2.313
2nd	1.691	2nd	2.292	2nd	2.619	2.88	3.04		4spd Low	1.959
3rd	1	3rd	1.41	3rd	1.516	1.67	1.67		Splitcase Stock	2.276
		4th	1	4th	1	1.10	1.00		Splitcase 3:1	3.1
				5th	0.845	0.93	0.75		Splitcase 4:1	4
									AA rock box	3.44
Effective Crawl Ratio in 1st Gear									NP 203 Doubler	2.0
Diff Ratio	3.73	4.1	4.56	4.88	5.29
Factory Ratio 3spd	23.79	26.15	29.08	31.12	33.73
Factory Ratio 4spd	25.98	28.55	31.76	33.99	36.84
Factory Ratio FJ60	30.18	33.17	36.90	39.48	42.80
H55F Factory Ratio	41.11	45.19	50.26	53.79	58.31
4spd Rock Box Only Low Ratio	45.61	50.14	55.77	59.68	64.69
4spd Rock Box Low Low	89.36	98.22	109.24	116.91	126.73
H42 Split Case 3:1	41.11	45.18	50.25	53.78	58.30
H42 Split Case 4:1 (or Orion)	53.04	58.30	64.84	69.39	75.22
H55F w/ 3:1	56.00	61.55	68.46	73.26	79.42
H55F w/ 4:1	72.26	79.43	88.34	94.54	102.48
NV4500 w/ factory split case	47.63	52.35	58.22	62.31	67.54
NV4500 w/ 3:1 Split Case	64.87	71.30	79.30	84.87	92.00
NV4500 w/ 4:1 Split Case	83.70	92.00	102.33	109.51	118.71

 

[KennyBob]

Thanks Mark. I have a nice spreadsheet, but not sure best way to share it. Considered a google sheets document, but I am concerned that would give access to my other personal files on my google drive.

Toyota J30		Toyota H42		Toyota H55f	Ratios	Effective H55 w/ 4:1 split case low gears & 1.1 high	NV4500		T-Case Low Gear Options
1st	2.757	1st	3.555	1st	4.843	5.33	5.61		3spd Low	2.313
2nd	1.691	2nd	2.292	2nd	2.619	2.88	3.04		4spd Low	1.959
3rd	1	3rd	1.41	3rd	1.516	1.67	1.67		Splitcase Stock	2.276
		4th	1	4th	1	1.10	1.00		Splitcase 3:1	3.1
				5th	0.845	0.93	0.75		Splitcase 4:1	4
									AA rock box	3.44
Effective Crawl Ratio in 1st Gear									NP 203 Doubler	2.0
Diff Ratio	3.73	4.1	4.56	4.88	5.29
Factory Ratio 3spd	23.79	26.15	29.08	31.12	33.73
Factory Ratio 4spd	25.98	28.55	31.76	33.99	36.84
Factory Ratio FJ60	30.18	33.17	36.90	39.48	42.80
H55F Factory Ratio	41.11	45.19	50.26	53.79	58.31
4spd Rock Box Only Low Ratio	45.61	50.14	55.77	59.68	64.69
4spd Rock Box Low Low	89.36	98.22	109.24	116.91	126.73
H42 Split Case 3:1	41.11	45.18	50.25	53.78	58.30
H42 Split Case 4:1 (or Orion)	53.04	58.30	64.84	69.39	75.22
H55F w/ 3:1	56.00	61.55	68.46	73.26	79.42
H55F w/ 4:1	72.26	79.43	88.34	94.54	102.48
NV4500 w/ factory split case	47.63	52.35	58.22	62.31	67.54
NV4500 w/ 3:1 Split Case	64.87	71.30	79.30	84.87	92.00
NV4500 w/ 4:1 Split Case	83.70	92.00	102.33	109.51	118.71

Very cool. I don't think a Google sheet will share anything but the file you choose to share. I understand your hesitation though. Could share it with someone you trust to make sure.

 

[red66toy]

This is such a cool mod, but I’m still wondering what the payoff is for going from a 3 speed to a 4 speed with the final ratio being the same. Is it just the difference in the ratios of the other gears in terms of drivability?

For me it was a two part upgrade. The original J30 was really clapped out. Once I took it out I could really see how bad a shape the gears and bearings were in. A lot of weird clunking and drivetrain noise is gone now that I put in a rebuild transmission. Second, and the biggest for me, was the much better gear spread as @EWheeler perfectly pointed out. Driving around in town and off road is, and will be, way better and smoother. You can keep the momentum going much better with the 4. The lower 1st of the 4speed is nice as well.
For the final drive ratio, I can hit 65mph no problem and that is really as fast as I want to go in a 40 anyways.

 

[65swb45]

I’ve had a lot of different rigs come through the shop in the last 34 years and got to drive basically every kind of transmission ever put in a 40. I really think the gear spread of the H42 is the best of all of them. Even the H55.

 

[matzell]

I’ve had a lot of different rigs come through the shop in the last 34 years and got to drive basically every kind of transmission ever put in a 40. I really think the gear spread of the H42 is the best of all of them. Even the H55.

I agree Mark! I am thinking up pulling a H55f to go back to a H42 in one of mine.

 

[peesalot]

Is it the 42 or th 41 have the deeper 1st gear ratio ? I am tired of the LARGE gap between 2nd & 3rd on the sm420, there should be 2 gears in that gap.

 

[matzell]

Is it the 42 or th 41 have the deeper 1st gear ratio ? I am tired of the LARGE gap between 2nd & 3rd on the sm420, there should be 2 gears in that gap.

H41, same as the H55f. I am debating swapping out my H41 Orion combo for a H55f split case 4:1 combo for more strength. With the 10 ud gears I would only net like 5-7% oberdrive but would have an even lower first gear and pick up a little speed in low range with 5th.

 

[peesalot]

More speed than low 5th, thats called 1st or 2nd high