putting in a 4speed, removing 3speed

[Vernon]

In searching the site, I have seen multiple posts on this process, but it is hard to combine all of the information from different posts.
My 4/73 FJ40 is all stock, 3 speed tranny, 3 speed t-case with PTO winch. I just want to get rid of the 3 speed and put in a 4 speed tranny. I have a 4 speed tranny but do not know what year it is.

Can anyone help or direct me with these questions?

- How do I identify what 4 speed I have and if it will work?
- Can anybody outline the process and list the parts/adapters that I will need.
- Also, are there any modifications to drivelines, mounts, etc.?

Thanks for your help in advance!

 

[trucruiser]

You will need a new bearing and a spacer to replace the PTO gear you take out and a new nose cone from the 4 speed.
I did it along time ago.
Search should turn up all of the part numbers as i dont have them anymore.

 

[Downey]

Several of us vendors sell a kit to adapt from a 4 speed tranny to a 3 speed transfer. These kits include a new drive gear that fits the 4 speed 16 tooth shaft, a machined spacer tube, new rear bearing, and some gaskets. You already know that you will need the 4 speed bellhousing and will have to swap around some drive shaft flanges. The 4 speed tranny is longer so drive shaft modification will be required. I don't know if you can retain the PTO winch, depends upon if you can find a new PTO drive gear for the 3 speed transfer that fits the 16 tooth shaft. Somebody here on Mud may have a part number for you???

 

[Living in the Past]

Count the splines on the tailshaft of the transmission. 16 will adapt to the 73 trnsfer case. 19 is for a split transfer case.

The nose cone is the same on the F engines. One from a B engine is different. You will need a special input transfer rear. 16 spline with 29 teeth. the four speedr transfer used a 31 tooth gear. The bearing and back (spacer,washer, nut) will need to be changed . You can find the 16 spline PTO gear and you will have to lengthen the drive line for the PTO as well as the shifting rod. Drivelines will need to have their lengths changed too.
Your 73 should fit right in without any problems by crossmember behind the transfer case. 73 Toyota already changed it for the four speed which was alvailable in other markets.

The PTO gears are not to hard to find I have few.

 

[Vernon]

Would it be any easier to install a 4speed tranny and a 4 speed transfer case? If so, could I keep the PTO winch? I am not sure if they equipped 1974 and later with PTO winches?

 

[Poser]

Would it be any easier to install a 4speed tranny and a 4 speed transfer case?

Yes.

If so, could I keep the PTO winch?

Yes.

I am not sure if they equipped 1974 and later with PTO winches?

They did.

 

[pc4400]

Sorry for the thread hijack

So will this work for my 72's 1F as well? And I won't loose my PTO?

 

[Living in the Past]

Sorry for the thread hijack

So will this work for my 72's 1F as well? And I won't loose my PTO?

As long as you get the right PTO gear for the tailshaft of the transmission inside the transfer case. The drive shaft needs to be about 3 1/2" longer. The same for the shift rod that goes from the handle back. I did this to my 68 back in 1994. I used the three transfer and changed the length of the drivelines. You don't have to change anything in the drive flanges that way. You will have more clearance issues in a 72 than in a 73. The crossmember behind the transfer case is a tight fit. But it ca be done.

 

[pc4400]

As long as you get the right PTO gear for the tailshaft of the transmission inside the transfer case. The drive shaft needs to be about 3 1/2" longer. The same for the shift rod that goes from the handle back. I did this to my 68 back in 1994. I used the three transfer and changed the length of the drivelines. You don't have to change anything in the drive flanges that way. You will have more clearance issues in a 72 than in a 73. The crossmember behind the transfer case is a tight fit. But it ca be done.

So how do like it? Much better on the highway?

 

[bsmith123]

3 to 4 speed

https://forum.ih8mud.com/40-55-series-tech/245021-pics-oem-p-ns-rear-main-clutch-change.html


I went from a 3 to 4 speed and changed over to a diaphragm style clutch while I was at it so my drivetrain is all 79 in my 71. Simplifies things somewhat

I lost my PTO which wouldve prolly happend for power steering later anyhow but on the bright side I picked up a Warn 8274 on MUD

THings to think about

Rear main seal change hwile you are in there
oil pan gasket
new holes for the shifter through the tunnel cover--easy to do just remove the shifter and mark from underneath with a sharpie
Rubber plug for the old PTO shift lever hole
trim for the 4WD lever
renew or inspect and assemble the park brake before you put the tranny in all the way otherwise you have to remove the rear mounts and tilt the engine down to clear the xmember

You need metric pipe for the driveshaft mod or the ds can be machined for std at addtl cost. The pipe is not all that common so you may have to order it in ahead of time for a quick turn on your DS

IIRC about 230 to do both front and rear