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Mysteries of the R154 R151 Gearbox.......

Cptsideways Feb 8, 2012

  1. Cptsideways

    Cptsideways Well-Known Member

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    Those of you with manual gearboxes in your 80 series may be wondering whats in there & perhaps why they appear so lumpy & reluctant to change gear.

    Well as it happens they are the same gearbox as found in Supra Turbo's known as the R154, the R151 is different in ratios, input output shaft & end casings otherwise its the same. Allegedly the LC box has tougher thrust washers too. As I seem to munch a few of these R154 gearboxes on a regular basis (nothing at all to do with 520bhp & 450ftlb of torque of course) I've got to the stage where need to be handy at fixing them. So here's the latest one thats in the garage today.

    Now there is a company in the states called Marlin Crawler who make a few upgrade parts for these & its well worthwhile fitting them for the minimal cost & its makes the boxes pretty much bombproof.

    Things that break:

    Centre Bearing Support Plate: this is made of cheese from the factory in R154's, they are pressed steel & flex under hard use, once stretched the bearing on input shaft wobbles about, if it gets really bad you can't select gears. Wose case it munches everything. Marlin Crawler make an upgraded part thats machined & its a lot lot tougher.

    1st/2nd Gear Thrust Washer: These break up due to shear/shock on high performance stuff anyway, usually caused by rapid shifting under load. Allegedly the LC one is not made of cheese, its a different part number to the Supra one but is otherwise identical.

    Things that are obviously a bit iffy: Upon investigation, when playing with the selector shafts it noticeable that the indents for the ball bearing detents are not machined well, they have a rough edge to them. This can make selecting rather crunchy I think as they slide through the steel centre plate. Some minor fettling with emery on the slot edges & they slide through the main housing like butter (they were like crunchy peanut butter before)

    Anyway some Pics

    The Marlin Crawler Bearing plate fitted V the old worn out one
    [​IMG]

    [​IMG]

    The detent slots that need fettling
    [​IMG]

    The mystery of the gearbox revealed
    [​IMG]
     
  2. BobMurphy

    BobMurphy Well-Known Member Supporter I am in england

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    Bootiful :thumbup: .

    You can keep all that electronic stuff . . I love GEARS :clap: .

    Bob.
     
  3. karl webster

    karl webster Land Cruiser Club sponsor Promoted Company Land Cruiser Club Promoted Company

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    Never seen inside a manual box. Very interesting. Just had a box swapped in the truck im using at the min as the box it had in was the worst ive had so far. Alot better now.

    Karl
     
  4. Chris

    Chris Super Moderator Supporter I am in europe

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    That makes me want a manual!! I can see a new enterprise venture for you there Capt!

    Chris
     
  5. Lorin

    Lorin Well-Known Member

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    I may be wrong but my understanding was that the gearbox in an 80 series is either H150 or H151. The R series gearbox was the manual from the 100 series and is reputed to be much weaker than the H series boxes....
     
  6. Towpack

    Towpack Well-Known Member

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    You are correct, the 80's did use the H series gearbox. Mine has never been lumpy or reluctant to change, just has quite a long throw from 1st to 2nd compared to most cars I've had.
     
  7. Cptsideways

    Cptsideways Well-Known Member

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    Aha that interesting, always though the 80's were R boxes. But did we get the manual boxes in the uk as a spare one or two might be handy.


    Anyway just fixed up a 2nd one today, just the casings to go back on now. (And no bits left over either!)
     
  8. Towpack

    Towpack Well-Known Member

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    All facelift ('95>) UK spec diesel 80's were manual. Only the petrols were auto. AFAIK someting to do with meeting emmisions.
     
  9. Rob

    Rob Well-Known Member I am in uk

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    Nice pictures Declan :thumbup:

    Just got a slightly off topic question, I have a H151 which keeps popping out of 1st gear in heavy over-run in low and high especially when off-roading. The 2nd gear synchromesh is quite bad, so bad that my girlfriend cant drive it when cold. In your opinion what parts need changing to put this right?
     
  10. Cptsideways

    Cptsideways Well-Known Member

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    That's usually just the syncro rings, maybe hub, parts are not that much if its just syncros. But most transmission p[laces will want to do a full rebuild (bearings syncros everything) but if it aint and worn out why I ask sometimes.
     
  11. Jon Wildsmith

    Jon Wildsmith Super Moderator Supporter Guru I am in england

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    Remember Ian took his to a gearbox specialist and it was never the same again even though they had several goes at it :roll: one of these days we'll get that box out my lockup and have a look inside to see what went wrong.
     
  12. roscoFJ73

    roscoFJ73 Member

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    Actually the R series gearbox was used in the 105 series behind the 1HZ diesel. The 105 is really an updated body sitting on whats really a slightly modified 80 series chassis.
    The 78/79 series landcruiser also used the R series gearbox from 99-06 in australia,except the turbo models with the 1HD FTE ,which got the H151
    The 100 series had the H gearboxes
     
  13. roscoFJ73

    roscoFJ73 Member

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    It would be pointless tearing down the gearbox and not doing a full rebuild. The kit itself is only a few hundred dollars,most of the cost is in the labour and because the box is in pieces it doesnt cost any extra in labour to do everything.
     
  14. Yaro

    Yaro Active Member

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    This is correct.
    80 and 100 series use H series, which are bigger and stronger than R series.
    R series are used in 7* series light duty (coil springs), 9* series, 120/125 series and 105 series (with 1HZ).
     
  15. frank rabbets

    frank rabbets Well-Known Member

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    I've just taken an 80 gearbox to bits. Most of the syncro rings are chewed and have been spinning past their three sprung locators. Also the output shaft thrust bearing is brocken into 3 pieces. Some of the syncro hubs have been put on the wrong way round and the RME manual does not show in sufficient clarity which way round to fit them or how to assemble them in themselves.

    I don't know if it is worth reassembling the box. For example 1st + 2nd syncro cones are chewed. They are 5 inches in diameter. How much are these likely to be and where can they be obtained? Also where can an accurate reassembly manual be obtained?

    Not a difficult job to rebuild one of these as long as nobody has been in before. Be careful to grind a little mark on all the parts of the syncro hubs and sleeves to reassemble in correct subassemblies and to ensure they go on the right way round. Trial and error is almost impossible because you have to build the whole internals up including selectors before you can see where you have gone wrong.

    Completely different to R box.

    Help !
    Frank
     
  16. Ian Rubie

    Ian Rubie Moderator I am in uk

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    This was my old gearbox. Anyone reading this should note that this box was rebuilt by a company called Gearlink based near Salisbury. They had 3 or 4 goes at getting it right before I just gave up and fitted a 2nd hand box. You can decide if you want to use them for your gearbox work :think:

    Ian
     
  17. Julian Voelcker

    Julian Voelcker Well-Known Member

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    We use a local firm and replacing the syncros is the most common problem we end up dealing with. If they are really bad the gears can get damaged as well, but the guys are pretty good and only change what is needed.
     
  18. Ecoman

    Ecoman Well-Known Member I am in scotland

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    On a similar note I would also steer well clear of Cleckheaton Clutch and Gearbox Centre (or any of their other pseudonyms) at Morley Carr Business Centre, Low Moor, Bradford. They completely fecked my Hilux gearbox, they had it back 3 times, promised to pay the extra labour charges run up by the garage and then when it didn't work a final time they told me they couldn't help me anymore. I was promised a full refund (including labour) and it never happened. I'm still owed £1200 by them. (Long story as to why I never got it back :x ). When I get the gearbox looked at by another company they said it looked like it had been put together with a hammer. Most of the gears needed welding, regrinding and shimming. The input shaft had been machined off centre and nearly every bearing had been damaged putting it in. :twisted:
     
  19. frank rabbets

    frank rabbets Well-Known Member

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    I think you had a narrow escape Ian. Your old gearbox was just about to go bang in a very big way. The output shaft thrust washer was in several pieces and these were running around the outside of the large gearwheel. The mainshaft had moved outwards as a consequence and the gearwheel was rubbing up against the casing. Also 30% of the rollers of the roller race between the input shaft and output shaft were up inside the input shaft having fallen out during assembly. This is a very easy 'box to work on with only a press needed; I can tell they did not have one; so any gearbox specialist would be doing this in their sleep.

    Frank
     
  20. Rob

    Rob Well-Known Member I am in uk

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    Could you post some pictures up of Ian's old gearbox, especially the bad bits so we know what to look for. Do you think the box is repairable?
     
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