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120 gearbox problem

Miklovan

New Member
Joined
Dec 21, 2018
Messages
11
Good day,

It’s been a while since I have a strange noise from my gearbox (5 gears / manual) while reversing “clunk-clunk”
Type of noise. Maybe because to go out of my yard I reverse on a steep hill every
time, can’t really know.
The other parts have been somehow eliminated because if the car is moving backwords without being in “reverse” gear there is no noise.
Question:
1. Would it be possible to install a 6 gears manual instead of my current gearbox (LC120 D4D ‘04) if a “fatal error” will occur?
2. Any idea if it’s a complicated fix to replace the damaged part from my gearbox - not to be handled by me but if it’s required mechanical “supe powers”?

thanks
Razvan
 
Hi Millovan i had a similar problem with my 120 but mine is an auto gear box, some of the problem turned out to be a faulty ecu and worn gear box mounts. The auto box was also faulty, but it did have a clunk and lurched forward when i put it in drive, it was fine in reverse. Hope this helps
 
Hi Millovan i had a similar problem with my 120 but mine is an auto gear box, some of the problem turned out to be a faulty ecu and worn gear box mounts. The auto box was also faulty, but it did have a clunk and lurched forward when i put it in drive, it was fine in reverse. Hope this helps

Sounds like you had a run of bad luck there - bad gear box, bad mounts, bad ecu!!! :-(

Which ECU was faulty, the transmission one or something else?

Which box was it, 4 speed or 5 speed? Haven't seen too many reports of 120 box failure on here?
 
It would be worth checking the front CV joints and also rear UJ joints.....
Can't think it's the gearbox without you having other gearbox related problems unless it's the reverse idler gear bearings ...
 
Hi Karl its a 5 speed, the engine ECU had the initial fault and it wouldn't change from 4th to 5th amongst other gearbox faults that where happening at the time, the auto gear box repair mechanic stated that he had never had a Toyota LC auto box in before and had to build a special electrical test rig to find the faults, the place was full of destroyed LRs with auto boxes that had melted. Since the rebuild its driven better than when I originally bought it, you can buy reconditioned ECUs which are very good but i bought a new one as i had spent that much on having the box rebuilt it seemed a little pointless to save a few bob on the ECU.
 
Thanks for the info! Wow - who diagnosed the ECU fault, was it Toyota?

How much was a new ECU if you don't mind me asking? I understand not skimping at that point! Thanks!
 
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Hi Karl the auto gearbox centre identified the ECU fault after building the test rig, I think the ECU was around £1000 - £1200 but to be honest i cant remember exactly but a recon started at around £250 onwards, which the mechanic told me would be fine as they came with a guarantee, the car still drives brilliantly and has a very smooth gear change.
 
Thanks for the info! Thats the main thing, that the car is sorted!

I tried to get an engine ECU a while back - couldn't find anyone who could test / recon them - all the usual companies I tried couldn't do 120. Ended up getting one from a breakers in the end, for about £400 or so.

Anyway, it turned out the original one was fine, and it was a mis diagnosis by Toyota. I suspect they use the ECU excuse when they cant be bothered with it, or its too hard. They were quoting about £1500 I think, but with 'no guarantee' that was the problem. Last time I bother with them!
 
It is not a big problem to repair the manual gearbox - mine is 6 gears and I did change all synchro rings on my own...
Maybe you could even replace yours with 6 gears but I am not sure if all will fit - especially the clutch as mine is kind of pull-type...
 
But if you send me your VIN and all other data I will check it for you... and also I would need a picture of a piston which actuates the clutch...
 
IMG_1859.JPG
 
So I have checked that, you would need to change also the clutch as the actuating lever is a different type. Your lever is pushing on the clutch, mine is the pulling type.
 
Thank you all,

I also blame the reverse bearing. I’m only afraid that it will take forever to get the part and I keep the car imobilized…(for my J70 I wait for two AC part for three weeks now).
I asked somebody who does only LC second hand parts amd he said that to swap the 5 gears with the 6 gears I need to change the shafts as well…if the clutch also needs to be changed it’s too much…
 
Most 120's are auto and seem to manage OK with 5 gears - are the manual box ratios that much different?
 
If the car is over 120km/h (~75m/h) my engine is at 3000rpm. I was thinking that a 6 gears box will drop the revs and reduce the “stress”. Good thing that we don’t have highways in my side of the country…
 
if you have currently gear box RA150F you have ration on 5th 0,838 and in diff 4.555, total is 3.817.
When you change just gear box for RA61F, you will have 0.799 on 6th and with your diff your total ration will be 3.639 which is slight improvement but far from original 3.12 which gains from diff ratio of 3.909.
 
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