r154 shifting experiences

[kemicalx]

Hi Guys,

When I bought my MZ21 Soarer it had just had an r154 conversion completed. From what i had read on the old forums and the US Supramania, I had gathered that they were a pretty heavy box and shifted like a tractor. So when I took my Soarer for a test drive and found it quite stiff to get into each gear I presumed this was the trade off for having a beefcake gearbox.

However, My mate Doobs picked up a manual MZ20 more recently, and the shift quality was soooo much smoother we presumed it had a w58 in it (which i've read has a v. nice shift) instead of the r154 it did in fact have.

My box didn't crunch into any gears so I presume the syncros are fine and although stiff once in gear it held tight and seemed to work perfectly fine.

I know Redline Lightweight Shockproof is the oil of choice for r154s but how noticeable is the difference between this and other fluids on the market? I'm basically trying to work out if I should crack open my r154 before I put it back in the car,

I also know I really should replace the 1st gear thrust washer, and there is a hairline fracture on what I think is the shift and select lever, though I don't see how it breaking could cause any damage to the box itself.

Here’s a picture of the piece in question:


So what are peoples experiences with the R154, oil choice and shift quality? Does it sound like there is anything seriously wrong with my box? If not it'll be going back in the way it is and I'll worry about sorting out the thrust washer when I change the clutch.

Thanks a lot everyone,
Ash

[EldarO]

i drove an r154 equipped car, i found it extremely reluctant to go into gear, compared to othe rmanuals ive driven.

i thought it was quite normal :/

Eldar.O.

[30psi 4agte]

When you pulled the shifter out was the ball and the plate that holds the shifter in place lubed up with some grease? That can help a little on the shift.

There was a article in a old High performance imports mag about thrust washers in these boxes as they are apparently prone to breaking.
The fix was to use the washer out of a landcruiser ( They are diff and alot stronger)


Lookin at your pic it looks like that crack is actually in the bottom of the shifter housing?

[kemicalx]

mmmk Doobs's r154 was v. nice, definatly no worse than any other I have experienced. I think his may have had Shockproof in it. And mine not. Don't supose you know what that part in the extention housing that has cracked is called?

[kemicalx]

Yerp, From what I've read the 1st gear thrust washer is cast and can break if stressed by tool like shifting, once busted they tear up the first gear set. When I replace it I'll take it to a machine shop and get them to machine a duplicate out of chromoly or something.

[30psi 4agte]

To me it looks like it is the bottom of the shifter housing itself that has cracked. ( i could be wrong )A little hard to make out from the pic.

Have a look at the underside of the shifter housing and see if you can see the crack

[BlackSupra]

Don't shift like you live your life a 1/4 mile at a time to help prevent the thrust washer issue.

When i first got my box i could barely select any gears. Redline shockproof and the box is 1000% better, but still shifts like a truck box versus a decent w58.

30psi gave some good advice, make sure the white shifter bush is in good condition on the end of the shifter, as a poor one will make for sloppy shifts. Tyhe top bush looks fine and the shifter linkage isnt too worn where the bush sits.

- New bush
- redline oil
- see how it goes

Opening it up will cost a bit of $$$

[kemicalx]

Cheers everyone, The shifter bush was pretty well greased up and looks to be in good nick. When I install it again i'll make sure everything is covered in grease..

[mrshin]

They're not my favourite cogbox... Of several I've driven, I too have found the shifting varies from firm to box-is-full-of-concrete. Plus they do seem to be quite breakable still, usually overpriced and sometimes noisy. There, now I've had my little sook for the day!

[kemicalx]

lol, the only real vulnerability I have heard of is the thrust washer. Once that’s fixed I thought they were damn near indestructible, at least it should be for the sort of power I plan on putting through it.

[ToranaJudd]

Kemicalx, I have included a link as the the first gear thrust washer problem. From memory there is another website that goes into more depth about complete dissasembly and reassembly of the gearbox. That page also includes the part number of a Toyota stocked chromoly washer for use in the R154 as the upgrade. Will stil search for that page and list it whej i find it, but in the mean time here is a little info of it with some piccies.

http://www.turbosupras.com/pages/en/...nical/R154.htm

Cheers Judd

[ToranaJudd]

Here is also a Complete guide for the dissasemble and reassemble of your R154 gearbox. Quite a good read, looks like on actual toyota manual. Still searching for the part number.

http://www.cygnusx1.net/supra/librar.../mt/MT_01.html

Cheers Judd.

[kemicalx]

thats a good writeup, cheers mate.

Thanks for the link to cygnus too, but a while I printted everything from that site relevant to the MZ20 and have two fat home made workshop manauls now Unfortunatly they are a little less descriptive than the usual noob-friendly Gregory/Haynes

[urantia]

same issue here, extremly difficult to get into gears. Most of the time i must double cluth to get the gear to go in without force, or without waiting until i am doing a very slow speed.

Going to try the redline gear oil, will let you know what difference it makes. I'm going to keep going with the stock thrust washer and hope for the best.

[Shifty]

It sounds like your clutch might not be disengaging correctly. Have you bled the clutch lately? Are the cylinders in good order?