H42 Transmission Question (1 Viewer)

[ukboneman]

I am coming to the end of my 1973 FJ40 resto-mod. I have done a 3 speed to 4 speed swap. I rebuilt the 4 speed and it seemed to go pretty well. I kept the 3 speed clutch. Everything runs great and it will shift up to 4 no problem. I can't, however, down shift without coming to a complete stop. Then, no problem - I can go into first and carry on my way. If I try to go from 3rd to 2nd without stopping - it won't happen. Any ideas? I am hoping that it is a clutch adjustment issue. I did replace the synchro rings during the rebuilt. Before I put the drift shafts back on, it would shift up and down without a problem.

 

[Pighead]

Any ideas?

Have you tried double-clutching on downshifts? Shouldn't have to but maybe it'll help. Have you learned how to shift (up and down) without a clutch? Can you do that?
I'm hoping it's just a clutch adjustment issue too...

 

[ToyotaMatt]

isn't a 3speed clutch set up not compatible with a 4speed gear box i thought ?

@Pighead you know this topic at all ?

 

[ukboneman]

everything I read said you could stick with the 3 speed or convert to a 4 speed clutch. I have not tried double clutching. I will. thanks

 

[Pighead]

isn't a 3speed clutch set up not compatible with a 4speed gear box i thought ?

@Pighead you know this topic at all ?

I have a tiny bit of experience here. My 12/'74 FJ55 came the the 1.5F naturally, a 4 speed tranny and 3 speed flywheel and clutch.
So, yes you can (imnshe) use 3 speed clutch components with a 4 speed transmission. But, you must use every single component for it to work. The clutch fork, throw-out, fork pivot, pushrod etc.

 

[ToyotaMatt]

I have a tiny bit of experience here. My 12/'74 FJ55 came the the 1.5F naturally, a 4 speed tranny and 3 speed flywheel and clutch.
So, yes you can (imnshe) use 3 speed clutch components with a 4 speed transmission. But, you must use every single component for it to work. The clutch fork, throw-out, fork pivot, pushrod etc.

perhaps this is a clue to help the thread starter ?

 

[Pighead]

everything I read said you could stick with the 3 speed or convert to a 4 speed clutch. I have not tried double clutching. I will. thanks

You should be able to shift gears without using the clutch at all. If yes, then it's the clutch. If not, look into the transmission.

 

[ukboneman]

I did use everything as described. The transmission shifted fine without the clutch on the frame. No problem at all. It appears to be having an issue after it is under load. Again, if I stop, you can shift right up to 4th no problem. I am worried it is the tranny.

 

[ukboneman]

FWIW

 

[Pighead]

Again, if I stop, you can shift right up to 4th no problem. I am worried it is the tranny.

Yes, that is troubling. Why i want to see if it is at all possible to shift without the usual clutch maneuver.
Any possibility you installed the wrong clutch fork pivot?

 

[ukboneman]

No, I definitely did not. The spring on my 3 speed fork was broken, so i had to get another fork with an intact spring. Made me very cognizant of my setup - 3 speed vs. 4 speed. The forks are very different. The clutch looks like it is functioning perfectly well. I have a bad feeling that it is the synchro ring. I think I replaced the 3rd and 4th gear rings but the lower gears were not available. Seemed to go together ok.

 

[Living in the Past]

isn't a 3speed clutch set up not compatible with a 4speed gear box i thought ?

@Pighead you know this topic at all ?

Kept my three speed clutch back in 1994 when I switched to a H42. Works fine as long as all the parts stay the same, including the flywheel. The clutch style didn't change until 8/74. Same time the fork, throw out bearing and flywheelchanged.

 

[ToyotaMatt]

Kept my three speed clutch back in 1994 when I switched to a H42. Works fine as long as all the parts stay the same, including the flywheel. The clutch style didn't change until 8/74. Same time the fork, throw out bearing and flywheelchanged.

what else John and @Pighead can cause this ?

can the shifter cane of been inststalled when all 3 or 4 of the selector RODS and DETENT springs balls were out of sync. some how perhaps ?


i had this happen to me in high skool in 1993 circa. that was along time ago , but i recall this a bit ....

 

[Steamer]

I think it may be improper or at least misleading to use the term 3 speed & 4 speed clutch. I think it would be better to refer to them as the 3-finger clutch and the diaphragm clutch. I say this because the 3-finger clutch carried into the four speed in 74 or maybe late 73. And as Living In the past pointed out. The 3-finger clutch goes with it's flywheel and has a step in it. And the flywheel changed when they went to the diaphragm clutch.

 

[ukboneman]

I did keep the flywheel and resrfaced it. That was a big reason I stayed with the three finger clutch - the flywheel was in great shape and I didn't want to get another one. Put in a new pressure plate. I used a 4 speed bell housing and undercover. I think the clutch and shift mechanism are ok. I can sit on the truck with the clutch depressed and shift through all 4 gears and reverse. I can take off and shift up to 4 no problem. When I go to down shift to 2, it's not that it grinds, it just won't go in. If it ground, I could ease it in whether or not the clutch was working. This just won't go in. When I stop, it goes into first, and I can shift back up to 4 if I want. The synchro rings on 1 and 2 are big and not available. I have a bad feeling that this was bad before I rebuilt it. Got it from a guy who was going to do a swap and never got around to it, so I don't know the history, but it looked pretty good.

 

[Steamer]

And I take it when the flywheel was resurfaced, they resurfaced both surfaces to maintain the proper depth of the step?

 

[ukboneman]

yes, I have a great machine shop - old school - and I gave him the specs I got off of MUD. It looked brand new.

 

[ukboneman]

So I took the truck back out this am. If I double or triple clutch, I can get it to go back into second, particularly if I rev it a bit between clutching. Maybe it is a top plate issue affecting fork alignment. I did take the top plate all apart during the rebuild, which was stupid as it was a pain and I really didn't do much other than clean it up. I have to believe that if it was a synchro/gear issue, I couldn't get it in or out of second at all. Going from 1 to 2 is no problem at all and even getting into first is pretty easy with a bit of speed. Could things just need to loosen up after the rebuild? It almost felt like it was getting better.

 

[Living in the Past]

what else John and @Pighead can cause this ?

can the shifter cane of been inststalled when all 3 or 4 of the selector RODS and DETENT springs balls were out of sync. some how perhaps ?


i had this happen to me in high skool in 1993 circa. that was along time ago , but i recall this a bit ....

Would be really hard to comment on what causing the problem without actually driving it in person. All the shift forks would have to be in the correct collars for it shift all the gears including reverse. The H42 is not like old GM three speed columns shifts from the fifties and sixties I drove as work trucks. Those it was possible to shift into two gears at once. Never able to do that on the couple FJ40 column shift three speeds. Four speed is a lot more work to pull on a pre 9/72 frame/tub. For that reason would be adjusting the clutch as a first step. A slipping clutch is easier to diagnose than one not completely disengaging. If you understand how to do it the H42 is possible to shift without using the clutch. Starting and stopping is difficult. Driving is fairly easy if your on a quiet road and not in traffic.

 

[ToyotaMatt]

So I took the truck back out this am. If I double or triple clutch, I can get it to go back into second, particularly if I rev it a bit between clutching. Maybe it is a top plate issue affecting fork alignment. I did take the top plate all apart during the rebuild, which was stupid as it was a pain and I really didn't do much other than clean it up. I have to believe that if it was a synchro/gear issue, I couldn't get it in or out of second at all. Going from 1 to 2 is no problem at all and even getting into first is pretty easy with a bit of speed. Could things just need to loosen up after the rebuild? It almost felt like it was getting better.

is this H42 a early style type with a cast iron 2 piece shift tower / top plate / plates assy. ?

or

a later 1piece ALL Aluminum Shift Tower assy. ?

also ,

please photos , and good crisp clear ones close up of the shifter cane receiver hole in the top plate / tower , focus in a photo of EACH of the 2 dowel pins inside the bore hole itself please .....


there is a very unique technical topic we need to evaluate , confirm and verify regarding the 2 small dowel pins i detail into above ....


after you report back these needed tech. photos , ill elaborate more as to why and stuff , but un-necessary speculation ramble on , can be a distraction here so ill wait to chatty matty up this topic then verse now ...



also :

- did u replace with NEW OEM parts the shifter cane retainer CUP thing , and the big spring itself in this focus point area im talking about ?

if NOT , ?

post photos or BOTH of the Twist-Lock female dowel pin retainer cut outs on the cane reciever tower too , that physically hold the shift cane in place please


this ALL related to one another topics ..fyi

if you don't understand what im referring to , don't be shy speak up , this is OK , ill post parts diagrams if necessary


matt