R154 5sp manual, stuck in 4th??

[Miles B]

Hey all, also posting this on Supraforums and ALSC.. anyone pulled a R154 apart before?
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Hi,
I have a R154 I bought out of a Mk3 Turbo.. the input and output shafts wouldn't turn, so I pulled the cases. It was in reverse, so I put it back into what should be neutral. Now it seems that it is stuck in 4th, as the input and output shafts turn at the same speed.

The syncro ring on (what I call) 4th, doesn't move like the synchros on the other gears. By "what I call 4th", I mean the front gear on the input shaft. What I want to do, is pull the input shaft out and see what is wrong with the syncro ring. Anyone got any tips for me? Following the manual, it says to basically pull the input and output shafts out as a unit, then pull them apart. I really don't want to pull all of the shift arms and forks and bearings and gears and crap.. just want to pull out the input shaft.

I think if I pull off the shift arm and fork on the hub for 3rd/4th, the input shaft might come out?? Anyone?

Help!

 

[mycarhasposessedme]

sounds like a jammed shift key or shift key spring on the 4th gear syncro.
yes miles you are right with the removing the shift fork shaft. undo the shift fork bolts on the top 2 shafts and then remove the circlips that stop lateral movement of the shafts. then slide the shafts back (i think they will move, they only have the spring loaded locating pin pushing against the side of them.)
next you need to undo the 4 bolts on the main shaft to intermediate plate bearing retainer if you can get to them.
you don't need much movement to get the input shaft to come away.
if it still won't come you will need to pull the number 5 gearspline piece to losen the cluster. a gear puller will do the job, and drive back on with a socket.
I'll have a bit of a think about it.

 

[Miles B]

Cool, that's about what I was thinking to get the input shaft out.. it already pulls out a little bit.. I am just a bit worried about how hard I'm gonna pull on it, as the sticking syncro also holds it on, but I have to pull hard enough to get that off... oh well, easy does it!

 

[mycarhasposessedme]

There you go, all done.

 

[Miles B]

Hopefully that's what mine will look like soon...

Unfortunately I snapped two of the bolts that hold the bellhousing to the box... one has a good half inch hanging out.. I'll weld a nut on it and try again I guess, but I imagine the threads are buggered.. the other is flush I think that's going to take heat, penetrating oil and a drill and extractor and hopefully i get it. Don't think the threads are buggered on that one, the bolt was just rusted and rooted. I wonder if the bellhousing can hang on without one of its bolts?

Apart from that, the gears all look in great condition...

 

[Miles B]

Hey mycar... you mentioned the overhaul kit is expensive.. any idea how much? I'd really like to replace that thrust washer while it's all apart.. got a part number for the kit? Might see if I can get hooked up by a friendly Toyota guy in NZ.

 

[Miles B]

OK the problem looks like 4th syncro is sticking to 4th. I need to pull the input shaft to see what is going on. Unfortunately, the 4th gear spline is slightly bigger than 4th, and catches on the 4th counter gear when pulling out the input shaft. I am going to see if I can take all the stuff off the counter shaft behind the intermediate plate. This should let me slide the counter shaft forward and pull out the input shaft.

What I need to know is how to pull the lock nut (I think the manual is saying to unbend the bits that are pushed in??), and how I put the 5th gear spline and stuff back on when I try to reassemble it all...

 

[mycarhasposessedme]

OK
First engage double meshing (engage 2 gears at once)
Then do as the manual says and unbend the locking tab on the nut.
Next undo the nut.
Disengage double meshing
Then you have to remove the no5 gearspline piece with a puller.
Everything else will then slide off.

Miles there is no rebuild kit as such available through Toyota.
You have to order all of the parts individually.
I got a price about 6mths ago on parts for a total rebuild,(from Toyota) it came in at around $2200.
you can get out of it cheaper without replacing the needle roller bearings in the gears.
They only ever need to be replaced on high mileage gearboxes.
I ended up getting onto a transmission specialist in the USA and purchased everything (all oem stuff) i wanted plus an after market intermediate bearing retainer for $500 US.
All up inc customs and GST was under $1000 AU.
If you are going to rebuild the box anyway I would suggest disassembling it in accordance with the factory service manual, as this method makes it easiest for reassembly.

 

[Miles B]

I really don't want to pull it all apart if I can help it. The box looks to be in decent shape, except for the stuck synchro. For the price, I would rather fit it, and risk smashing the first gear thrust washer. Another box isn't that bad anyway.

I figure with all the people who push good numbers through MA70 turbos with these boxes without smashing washers, I got a good chance at getting out of it OK.

I found this on the web.... http://www.drivetrain.com/toyotaR150rwd.html

One other thing.. when I tipped the box up on the extension housing, oil leaked out. I haven't found mention of a seal in there.. would that be the "Rear Bushing" they list?

 

[Lextreme II]

Miles,

From the above link.


Toyota Supra Turbo 1987-93

T100 V6 1993-97

Tacoma V6 1995-97

Truck Turbo 1985-88

Truck V6 1987-94

4-Runner V6 1987-97



So those trucks have R154?

 

[Miles B]

Yep! Well, in the R150 family - not sure of any differences?? I believe some of them are 4WD too - they have a transfer case on the back. It has been raised on ALSC that there was a 4WD Aristo in Japan, that had a 1UZ, that could possibly have its front sump and axle grafted onto an SC400...

 

[mycarhasposessedme]

Miles
The R154 does share a lot of components with the r150 and most of the rebuild parts are compatible but not all.
The rear seal on the extension housing where the tailshaft yoke goes in is the only rear seal. If you had no yoke in oil will come out.
There is another gearbox that Aisin (they made the R154 for Toyota) used the same tooling they used to make the R154 and R150 to build for Jeep it is called the AX-15
and shares almost all rebuild components. However the parts for this box are cheaper to buy from Mopar than the same parts are through Toyota even though they all come from Aisin Japan.
The transmission rebuild kit I used was put together by using all of the available interchangable parts from Mopar (some syncro's, some bearings, etc) and the R154 specific parts genuine from Toyota.
I would recomend checking the syncro's for wear as per the FSM before deciding not to rebuild Miles as you could do a partial and just do the syncros and rear bearing.
The box in the above picture was a low K Japanese import that externally and internally looked brand new, however the syncros were worn beyond the factory limit.
They still worked ok but would have started to be a problem in the near future.
This is how people start to break shift forks etc, from forcing worn syncros to engage.
There is nothing like a freshly rebuilt transmission, providing its been done properly.
Remember the old saying (sh1t i sound like my father) a stitch in time saves nine.
I'll leave you on that note.

 

[Miles B]

OK I've pulled my box apart, and now it's almost back together. The problem was 4th's synchro was sticking onto 4th after the #2 hub is shifted back to neutral. Looks to me like the synchro just works too well. Maybe it is new or something, the whole damn box looks pretty mint to me. The synchros are right off the scale - over 1mm clearance left. The guy I bought it from did say something about reconditioning, but I didn't believe him. My hope is that the synchro just needs wearing in a bit. When I get it in the car, I will just drive it along in 4th, then put it in neutral and make sure it can break free.

That is, if I can get the bastard back together and shifting properly now! It was stuck on 4th so long (probably a year now), that when I first tried it, I couldn't get it shifting at all. It was also in reverse. Notchy didn't even come close to describing it!

If I cared enough, I'd order the full rebuild kit, and get all the gears and stuff cleaned, there is a lot of sludge hanging around. But hell, if it blows up, which it probably won't, I'll just get another one on the cheap for less than a rebuild kit costs.

A few notes... if you are just pulling the input shaft (to save having to buy a new rear output shaft bearing, it's a bitch. The 3/4 hub is a tight squeeze to get out, as is the 5 hub. BOTH squeeze past the other shaft's bearings! When you pull out the input shaft, DO NOT pull out the 3/4 hub. Getting the keys back in is a bitch - there is a spring on the other side you can't get to easily! Driving the 5th gear spline back on without the special tool is easy - use the old throwout bearing!

 

[mycarhasposessedme]

You can use valve lapping compound to bed the sincro if it seems to be a bit sticky, but you must be sure you can clean it all away when finished.

 

[Miles B]

Is it better to pull it back apart and do that, or just leave it in and hope the car wears it in for me? How would I do it, just by hand or what?

 

[mycarhasposessedme]

If it were me I would lap it in as it already has stuck once and i'm sure you wont want to pull it all out if it sticks again.
Yes you will have to pull it back apart to do this and yes it is a done by hand thing.
Once you have it apart place a small amount of valve lapping compound (if you have coarse and fine use fine)around the shiny mating face of the gear spline end on fourth gear then place the syncro over the top , now push down and turn the syncro around and around about half a dozen times.
This should take off whatever is causing the problem.

 

[Miles B]

Sweet, will go grab a lapping kit tomorrow and give it a go.. lucky I didn't quite finish putting it all back together last night!

 

[mycarhasposessedme]

Good luck Miles, just remember to give it all a good clean with a toothbrush or something as the lapping paste gets right in between all the grooves in the syncro ring.
You can imagine what a bit of that stuff roaming around in a gearbox will do.
Seeya.