Downshifting H55F into 2nd when in 4wd (1 Viewer)

[Spook50]

Driving in to work this morning the highway was a mess, so I was in 4WD for nearly the entire drive. As I was exiting the highway and slowing down, I discovered that my tranny didn't want to downshift into 2nd gear. Shifting back into 3rd or up into 4th were no problem, so I don't suspect a clutch issue. Trying to go into 2nd it would grind as if not even synchronized until I was down to about 5MPH, then I was able to engage it with more than the normal amount of force. I attempted to double clutch and that made no difference either, plus the ability to shift smoothly into 4th made me think it's not a 2/4 synchro issue either. Back in 2WD, no problem at all.

So given that I'm still in the learning phase of owning and maintaining an H55F, I'm confused on this one. I would suspect that being in 4WD versus 2WD shouldn't make any difference, and the two most likely culprits (to me), don't seem to be the cause. I have no reason to think the oil level is low, but I'll be checking that at the first opportunity just to be sure. I use Red Line MT-90 oil in it as well.

Any suggestions on what I can do to narrow down the cause, or just tell me "it's normal, dummy"?

 

[cps432]

That’s weird. I don’t have an answer for you other than to say my H55f has been grinding when shifting from 1 to 2 on rare occasions. I thought it was an issue with my foot not depressing the clutch pedal completely before I shift but I’m pretty sure it’s not the case. I also notice that I’m able to shift through gears 1-4 without using the clutch when the engine is off. I have to use the clutch for 5th gear. Most times when I park I can pop the transmission in and out or gear without the clutch. Some times I cannot. There are some strange little quirks that I haven’t quite figured out with this thing. I’m curious about your issue now.

 

[HemiAlex]

I’ve had mine get sticky and make a clicky noise in 2/3 when I’m in 4wd for long periods.

It's never caused an issue, once it cools off it goes back to normal. I've put 40,000 miles on this trans from new.

 

[OSS]

Highway driving in 4WD (in a 60 series) is guaranteed to create driveline binding problems. The front wheels are spinning at a slightly different speed than the rears. That build up of pressure has got to be released somehow. Either the tires eventually slip to release the tension or the imbalance in driveshaft rotation front & rear will eventually cause so much binding that the car won’t roll properly.


It’s not really very easy to downshift the H55F into second gear at speed without major grinding without being an expert at double clutching it. This pretty much holds true at any speed except rolling up to a stop sign. (In my experience).
The fact that you can normally do it in 2WD is news to me. Mine never could.

The transmission has no idea whether you’re in 2WD or 4WD. The transfer case gears sure as hell know, but the transmission is oblivious to it.
It’s output shaft is clueless to the mayhem that 4WD on pavement is creating in the transfer case.

As to why shifting down to 2nd while you were in 4WD was difficult but easy once you switched back to 2WD, may have just been a coincidence. Other factors could have been at play not related to 4WD like the attitude of the vehicle, whether you were decelerating and maybe just a bad shift.

I wouldn’t throw 4WD under the bus quite yet as the bad shifting culprit until you can duplicate the test scenario with certainty.

 

[Spook50]

Highway driving in 4WD (in a 60 series) is guaranteed to create driveline binding problems. The front wheels are spinning at a slightly different speed than the rears. That build up of pressure has got to be released somehow. Either the tires eventually slip to release the tension or the imbalance in driveshaft rotation front & rear will eventually cause so much binding that the car won’t roll properly.


It’s not really very easy to downshift the H55F into second gear at speed without major grinding without being an expert at double clutching it. This pretty much holds true at any speed except rolling up to a stop sign. (In my experience).
The fact that you can normally do it in 2WD is news to me. Mine never could.

The transmission has no idea whether you’re in 2WD or 4WD. The transfer case gears sure as hell know, but the transmission is oblivious to it.
It’s output shaft is clueless to the mayhem that 4WD on pavement is creating in the transfer case.

As to why shifting down to 2nd while you were in 4WD was difficult but easy once you switched back to 2WD, may have just been a coincidence. Other factors could have been at play not related to 4WD like the attitude of the vehicle, whether you were decelerating and maybe just a bad shift.

I wouldn’t throw 4WD under the bus quite yet as the bad shifting culprit until you can duplicate the test scenario with certainty.

Very true on the binding. Exactly why I avoid using 4WD on dry or (above freezing) wet roads. I also suspect that, combined with typical wear, is why my transfer case growls so loudly when in 4WD under partial throttle.

In normal conditions I can typically downshift into 2nd when under ~20MPH. Any faster and it wouldn't go, but, it wouldn't grind like it was this morning when I was almost to work. This was at already sub-20 speed, so I was well under highway speed when I attempted to downshift.

Also good point on the transfer engagement having no bearing on the operation of the tranny. Confirms my thoughts as well, based on my knowledge of our drivetrains.

I had played around some this morning on the low speed roads just outside my work with the same results, with double clutching making no difference. I'll putt around more this afternoon once I'm off and see what it'll do. With the current weather it may be a while before I'm driving on dry pavement in 2WD, but I'll certainly be paying closer attention to its downshift behavior when going into 2nd. What's also interesting is 5 to 4 and 4 to 3 had no issues in 4WD, which is nearly always my first action to decrease speed in winter conditions, or prevent runaway speeds when descending steep hills.

 

[Spook50]

Looks like it's not just downshifting. When I start in 1st and upshift into 2nd it's getting hard to find also. I would wonder if there's a problem with the synchro, but if there were, wouldn't I be having issues with 4th gear also? The synchros are set up as 1/3 and 2/4 with another exclusively for 5th, correct?

What I have not yet tried since it started this morning is with the hubs unlocked to see if it goes back to normal that way. With the hubs unlocked I can coast around a corner, drop into 2nd as I'm turning and it's smooth as silk. Hubs have been locked though in and out of 4WD throughout today, and 2nd grinds like crazy when I navigate corners. Can't for the life of me remember if I had this happening last winter or not.

 

[2mbb]

my H55F has always been chunky. Doesn't matter if 2WD or 4WD. 2nd gear is the worst. I find I hold the shifter at shift "gate" and apply moderate pressure and eventually it will pop into gear. Speed shifts are not an option. It adds to the "going slow" experience of the vehicle.

 

[OSS]

Definitely check the fluid level in the transmission. If it’s high or low it won’t shift as smoothly. If it’s high or low — check the fluid level in the transfer case too.

 

[FJBen]

My H55f 524,000km's on it and still shifts pretty dang good. The only issue I have is 2nd will sometimes give a tiny little grind if I shift too fast in colder weather. Other than that it's smooth. I agree too that you can get 4WD bind, but I haven't ever noticed that 3~2 downshift in 4WD causing any issues. I should be able to try soon as weather will be turning and I'll be snow driving.

@cps432 I'm able to shift in and out of all gears without the clutch with the engine off.


I have videos of my shifting while testing other mods and it seems to shift "biskly"

 

[Fedtime]

I had a similar issue with my BJ60, but with 5th gear. It would grind going into gear and sometimes pop out of gear. I figured it was synchro related and was getting ready to start pulling things apart when I noticed that the front driveshaft looked odd. Turns out it was hung up on some dirt and rust and not sliding freely. Once freed up, the problem resolved. Just a thought.

 

[Spook50]

I checked my oil today, and about half a quart spilled out of my tranny, while the tcase was also about half a quart low. So there's definitely oil shifting from one to the other. Luckily I use the same oil in both gearboxes, so I topped off the tcase and drove it around town.

Unfortunately 2nd gear is still grinding. It seems to be just coincidence that it started yesterday, the first day I seriously used 4WD this season for my commute. There was enough melt today that I unlocked my hubs and it made no difference. 2nd grinds heavily if I try to shift normally into it at any speed over about 7MPH, either from 1st or from 3rd, accelerating or decelerating. I'm suspecting more and more that the synchro is failing. 3rd has been notchy but not horrible since fall of last year, but it looks like a rebuild is in order for next summer. What strikes me as odd is that double clutching into 3rd makes it shift smooth as butter, but double clutching makes NO difference with what's happening in 2nd gear.

With any luck, hopefully I can afford to put in a low range gearset (with necessary parts) from @orangefj45 in my tcase when I tackle this job.

When I'm ready to start ordering parts I'll start a new thread that can hopefully serve as a parts inventory and rebuild primer for H55F users (myself included of course).

 

[tmxmotorsports]

@Spook50 was the transmission new?

 

[Spook50]

@Spook50 was the transmission new?

No, it was a rebuild that had IIRC about 5K miles on it before the vehicle it was in rolled, then sat in my shop for 10 years before finally being swapped in. Worked perfectly for several months, then 3rd got just a touch notchy which seemed to be on par for a syncro beginning to wear (but still easily driveable), then just yesterday the 2/4 synchro started acting up.

 

[tmxmotorsports]

Ok may have no relation but I had a 60 here in the shop hard shifting into every gear and it was the bushing in the shifter housing also was a 4 speed manual just throwing this out there

 

[Spook50]

Ok may have no relation but I had a 60 here in the shop hard shifting into every gear and it was the bushing in the shifter housing also was a 4 speed manual just throwing this out there

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I had put a new bushing in spring of last year, but the bottom and top parts did separate like what's in your pics. I didn't think anything of it, but is it possible that could affect shifting? I didn't think it would make any difference, but that was only based off the fact that the Marlin shift bushings for other Toyota trannnies (they don't make one large enough for the H55F) are only the top portion as well. Are the H42 and H55F different in that aspect?

Edit: looking closer that may not be the case. Looks like you're showing the old H42 bushing next to the new one? On the H55F the bushing has kind of an inverted cup on the underside of the bushing, I assume to prevent oil from splashing up out of the shifter housing. Here's a pic I found of one upside-down:

 

[FJ60Seth]

You can examine the trans internals by removing the top plate. It a lot of work to pull the seats, carpet and hump, but not challenging or complicated like pulling the trans and tcase.

 

[Spook50]

You can examine the trans internals by removing the top plate. It a lot of work to pull the seats, carpet and hump, but not challenging or complicated like pulling the trans and tcase.

I have a bad feeling it's going to come down to that. Though like you said better than pulling the tranny in its entirety if that can be avoided. Luckily I still don't have any carpet in place so that eliminates removal of the seats too

 

[tmxmotorsports]

Yes the pics are of the new bushing and the old or what was left of the old one they must be different than the h55 from your picture the 4 speed manual doesn't have the top portion has a rubber boot that goes over the shifter and housing

 

[Spook50]

Yes the pics are of the new bushing and the old or what was left of the old one they must be different than the h55 from your picture the 4 speed manual doesn't have the top portion has a rubber boot that goes over the shifter and housing

Funny enough mine has the "underboot" too....