I've had it.

[B92 8NW]

I've got no idea what the hell is going on with my gearbox.

I mentioned that I couldn't select 1st as I thought the clutch was dragging. Then I appeared quite the tool when it worked fine for my mechy. Well on boxing day, after landing no bargains at Shepparton Ray's Outdoors, the synchro on gear 1 seemed to self destruct in the depths of Strathbogie. Got it back to my place, provided I double declutched it was fine, in fact "magically" smooth.

Drove 300kms with it grinding to buggery at every set of lights yesterday. Starting ringing places to have the transmission rebuilt:(...

...until this morning, it was fine and I was able to drive all the way back to Melbourne without a problem. It shifted excellently through every gear...

...until work this evening when it regressed into its unsynchro state.


I thought when I bought a Disco I was giving up the half synchro IIA box, so tell me, why the hell should I drive the disco if I have a half synchro IIA to drive????:mad::mad:

How could it possibly intermittently lose synchro???

PS. There was a correlation between temperature and synchro faults, however as of yesterday it was grinding from dead cold in the morning to full operating temp on the highway under load.

Dropping the fluid in 30mins as its currently too hot, shame as it was bloody expensive synth ATF and its only been in 4.5k, I'm expecting to lots of metallic rubbish.

Anyone got an LT77, preferably 93-94?:(:(

[mcrover]

I'd be more looking at your clutch master cylinder.

When your doubling it is increasing the amount of throw on the clutch fork and then you can get gears.

If not the master cyl then probably likely to be the clutch.

If the syncro broke you would most likely have no drive in 1st.

[Graeme]

Joel,
Did you try selecting 2nd instead of 1st, then 1st (quickly) once 2nd has stopped the box? Does selecting 2nd also grind, or is quite hard to engage? Yes to either suggests the clutch isn't disengaging.

[DEFENDERZOOK]

with the vehicle stationary........if you press the clutch just once.....and hold it for a few seconds.....can you select reverse.....?


if you pump the clutch a few times......can you then select first without any crunching.......?


and if you are in first....with your foot on the clutch......will it start to creep away after say 30-60 seconds...such as waiting at an intersection in gear ready to take off.........?
make sure there is noone infront of you when you do this test......as you wont be able to pull it back out of gear unless you either take off.....or switch off the engine......


let us know your results......

[Graeme]

I agree with MCROVER - clutch master cylinder working properly only sometimes.

[B92 8NW]

with the vehicle stationary........if you press the clutch just once.....and hold it for a few seconds.....can you select reverse.....? Yes, it selects reverse correctly after 2-3 seconds.


if you pump the clutch a few times......can you then select first without any crunching.......? No, pumping the clutch a few times doesn't make a difference, it still crunches.


and if you are in first....with your foot on the clutch......will it start to creep away after say 30-60 seconds...such as waiting at an intersection in gear ready to take off.........? Nope, it doesn't start to creep away
make sure there is noone infront of you when you do this test......as you wont be able to pull it back out of gear unless you either take off.....or switch off the engine......


let us know your results......

Hi defenderzook

as above

regards,

[B92 8NW]

Joel,
Did you try selecting 2nd instead of 1st, then 1st (quickly) once 2nd has stopped the box? Yes I've tried that, but it still does not engage 1st unless I allow the vehicle to roll to a complete stop. Does selecting 2nd also grind, or is quite hard to engage? Yes to either suggests the clutch isn't disengaging. 2nd doesn't grind nor is it hard to engage, but it has always had a slight normal LT77 "notchiness"

Hi Graeme,

as above

Regards,

[DEFENDERZOOK]

Hi defenderzook

as above

regards,




well....that eliminates the clutch........the problem must lie in the box......
not what you wanted to hear......

[B92 8NW]

well....that eliminates the clutch........the problem must lie in the box......
not what you wanted to hear......

****

Probably a good time to admit too, that at 290,000 km half a circlip drained out of the gearbox. Now have 305,500 notched up.

[DEFENDERZOOK]

the damage may not be too bad.....yet.....


avoid driving it till you can investigate it further.........
in laymans terms......stop driving it or you will do more damage......

[mcrover]

Forgive me for my ignorance but are you sure the box is LT77 and not R380 or are we not talking about your Disco here?

If R380, 1st and 2nd are on the same syncro pack so if you lost 1 you would more than likely lose the other but I no nothing about the LT77 so I cant coment.

Im still thinking it would be more clutch related if it is intermitant as once your moving and if you were changing at the correct revs/speed then you wouldnt need to use the clutch to change up but changing down might be interesting with out blipping the throttle.

I suppose it could have worn the grooves in the syncro ring and that would have that sort of effect but it wouldnt be intermittant or it may be full of crud and dislodging it every now and then.

Too many things it could be with out driving the car for my self I dont think I could pin point it on here.

:- is there noises?
:- What does the pedal feel like?
:- What does the change from 2nd back to 1st feel like?

etc etc

You may be on the money but I wuld start at the easy/cheaper stuff first and work to the pricey stuff later rather than throwing money at it while not having it properly diagnosed.

By the way Im not saying you dont know what your on about before I get chewed out but there is a lot of feel etc involved in stuff like this so get a second opinion from a LR mechanic or some one in the know.

[graceysdad]

Did you apply emergency repair procedure number one? which is hit it with a big hammer, if problem persists consult your doctor

[B92 8NW]

Forgive me for my ignorance but are you sure the box is LT77 and not R380 or are we not talking about your Disco here? My Disco is a 1994MY, LA chassis so its before the update. It has the LT77S (reverse top left, with the 'S' standing for revised synchromesh:D, yeh righhhhhttt)

If R380, 1st and 2nd are on the same syncro pack so if you lost 1 you would more than likely lose the other but I no nothing about the LT77 so I cant coment.

Im still thinking it would be more clutch related if it is intermitant as once your moving and if you were changing at the correct revs/speed then you wouldnt need to use the clutch to change up but changing down might be interesting with out blipping the throttle. Yes, if I shift 2nd to 1st double clutch blipping the throttle it goes straight in nicely.

I suppose it could have worn the grooves in the syncro ring and that would have that sort of effect but it wouldnt be intermittant or it may be full of crud and dislodging it every now and then.

Too many things it could be with out driving the car for my self I dont think I could pin point it on here.

:- is there noises?
:- What does the pedal feel like?
:- What does the change from 2nd back to 1st feel like?

etc etc

You may be on the money but I wuld start at the easy/cheaper stuff first and work to the pricey stuff later rather than throwing money at it while not having it properly diagnosed.

By the way Im not saying you dont know what your on about (Actually this is quite correct, I'll be the first to admit I'm not good on the transmission side of things, I've never worked on one before.) before I get chewed out but there is a lot of feel etc involved in stuff like this so get a second opinion from a LR mechanic or some one in the know. Any good referrals you know as my current one couldn't find a problem?

^^^:D

[mcrover]

Where in town are you?

[Graeme]

****

Probably a good time to admit too, that at 290,000 km half a circlip drained out of the gearbox. Now have 305,500 notched up.
Now that's not a good sign!

It sounds as though the circlip may have come from the synchro hub and its affecting only the 1st gear side.

I had assumed that the problem was occurring whilst stopped rather than still moving, hence the clutch thought.

[Blknight.aus]

with the syncro setup its entirely possable that all you have is a worn cone on the syncro, the most common cause of this is downshifting to first at speed (OOMA say over 5kph), once the cone wears away enough the thing will no longer seat correctly in gear and will "rattle" in place and eat the retaining circlip and possabley the guiding slides for the syncro pack.

Heres the good news Its entirely possable that all you have damaged is the syncros themselves as they are about the softest metal in the gearbox however prudence dictates that as replacing the syncros pretty much requires a complete rebuild of the box you might as well rebuild it ESP if your doing it as a DIY. Yes IMHO if you own or can borrow a set of feeler gauges and a DTI with the manual and putting your fear of it on hold all of the rover manuals are a DIY ESP if youve done something as finicky as say replacing the swivel pin bushes + bearings on a landy.

Avoid driving it as much as you can as while its spitting metal bits out theres the chance that something is going to wind up somewhere you dont want it.

[B92 8NW]

Where in town are you?

Mont Albert North 3129

[Bulldog]

Mine's a different box, but it was always a challenge to get it into gear. 2nd would always crunch (even heard a 'crunch, tink, tink, tink' once :o). It would never go into reverse unless i waited 20-30 seconds or forced it in (crunch!). Clutch master died the other week, so i put a new one in with new hoses. All problems gone now (goes thru the gears nicely).

I am no expert in any way, but this may help ;)

[B92 8NW]

I've just come inside from changing the gearbox oil and I am completely mortified by the fluid that drained out.

The drain plug was full of filings, as was the extension case filter.

The worst part was the Transmax Z that had only done 4,500 km. It has lost its translucency and its completely opaque, loaded with swarf. It looks like a metallic green paint colour. I'm also assuming that the geartrain has sheared it to buggery as it is as thin as water, far thinner than when it went in.

I know a simple fluid change will not fix a problem, but I'm off for a drive now and when I get back I'll post a few pictures of the old fluid.

[B92 8NW]

Test driven and everything is 100000 times better, 2nd to 1st still needs a double de clutch but all other notchiness has gone and the box feels much tighter and smoother. It no longer whines at low revs, I will take it onto the freeway later and see how whiny 5th is at low revs.

I have now successfully converted from using ATF - all previous posts where I advocate the use of ATF I now revoke.

As for the grinding 2-1, I can accept that damage has occurred and needs repairing. I reckon I can safely drive it provided I shift 2-1 once stationary, until the 7th when my mechanic reopens. I will certainly be bottling the fluid for him to see.

Excuse the crap quality.

https://www.aulro.com/afvb/images/imported/2007/12/62.jpg

https://www.aulro.com/afvb/images/imported/2009/07/1240.jpg

[awabbit6]

That oil doesn't look good. This is one of the reasons that I put gear oil in my box rather than ATF. I had a bad experience with it once in an old Datsun gearbox. A gearbox tech reccomended that the ATF would fix my crook syncros, and it did ... but it destroyed the new bearings in 6 months.
My Disco box has been great with the semi synthetic gear oil I put in it.

When reading you post earlier I was going to suggest a selector problem, but seeing that oil, there is definitely more to it. I hope all goes well and there aren't too many bits floating around when it is pulled down. You may have just got it in time.

[Ace]

just get a reco box and use the correct oil, its done 300000km, and for some of that has had the wrong oil in it. I have never heard of using ATF in a manual box, i use Caltex MTF94 which has been made for the Land Rover manual box, however mine is the R380 so not sure on the ones that preceed that. lately i have been using Valovoline gear oil, not the 80w/90 the one under that and its noiser than the Caltex oil was so i am going to swap back when i can get some of the caltex oil.

[B92 8NW]

The difficult thing is that the LT77 since its inception and right up to the current day, Land Rover advise ATF. I've tried the R380 MTF94 fluid and it was a nightmare. Far too notchy and when cold it was impossible to select gears. Service history shows that it has always had Mobil ATF 210 from new, then Mobil ATF 11E which superseded ATF 210, so consequently it has always had the right fluid in it.

The dilemma therefore is finding something of low enough viscosity to be smooth yet something that provides decent protection. I've refilled today with Kubota UDT (Mobil Agri Fluid 424) because it has a KV between ATF and MTF94 and sufficient EP additives and frictional characteristics to protect the thing.

I've done 70 km and it is shifting far better, but the 2-1 problem is still intermittent which leads me to believe it may be the clutch master cyl after all. FWIW I'm going to spend the $250 and replace both master and slave cyls before pulling the box down.

[Blknight.aus]

save the $250 the master cylinder can be replaced with a similar sized PBR jobbie from a trailer shop for $80ish from memory and the slave can be sleeved and rebuilt for about $60.

pull em out yourself and then refit the new ones or as a temporary fix if your going to do it anyway bleed the system up using chainsaw bar oil, its rough as guts but it will prove one way or another that the clutch system is the culprit. Bewarned tho If you do this you HAVE to rebuild the clutch hyd system anyway.

[justinc]

Joel,

I have seen your Oil picture, NOT nice.
I would suggest also that it may be the oil pump that has either worn out and is bypassing, or the drive has failed, or more commonly the corrosion protection that LR put on the inside of the box(Literally a paint) has all flaked off and coated the oil pump pickup screen and blocked it= no oil to the pump= no lube to mainshft brgs and synchros except splash only. Not enough.

I always get the gearbox case acid bathed to rid it of this troublesome coating before rebuilding.

I have used ATF in ALL LT77's for all the years I have been working on and rebuilding these, and never had a problem with shift quality or longevity.(Except those with the pre upgraded 2nd synchro hub )

Having said this, I can't comment on high ambient temp protection with ATF, I would assume a 75w85 synthetic or MTF 94 may be better in 40+ degrees.(?)

Oil feed also depends on the ferrobestos bushing/ oil ring in the rear extrension housing, I have seen these blocked up etc aswell causing lack of adequate lube.

Hope it gets sorted OK.:(


JC

[lewy]

keep us posted,i also found a half circlip in the oil.about 160000km,i now have 250000 and still use atf.just a thought could of the synthetic oil cleaned the "special paint"of the inside of the gearbox and blocked the pump,good luck

[B92 8NW]

keep us posted,i also found a half circlip in the oil.about 160000km,i now have 250000 and still use atf.just a thought could of the synthetic oil cleaned the "special paint"of the inside of the gearbox and blocked the pump,good luck

I'm really not sure, no flakes of paint came out in the oil that I drained, nor did the filter have any flakes in either. I just can't understand why this time around there was so many metal particles, it has never been that bad before. It almost beggars belief that a good synthetic ATF could cause greater metal wear than a plain ATF, especially after 4,500 kms! I was intending leaving that in for 20,000 as per the manual, by 20,000 it would have been so heavily laden with metal that it would have resembled mercury!



I have seen your Oil picture, NOT nice.
I would suggest also that it may be the oil pump that has either worn out and is bypassing, or the drive has failed, or more commonly the corrosion protection that LR put on the inside of the box(Literally a paint) has all flaked off and coated the oil pump pickup screen and blocked it= no oil to the pump= no lube to mainshft brgs and synchros except splash only. Not enough.

Interesting! It sounds very likely that the pump is not operating correctly given the level of metal wear.

[Sprint]

i know this isnt exactly the answer anyone is looking for, but in the T5 manuals in falcons and commodores, when ford were having issues with baulking shifts when using gear oil, they switched to DEXIII ATF and an additive called lubrizol for the 6cyl's but retained a 75/90 gear oil for the V8's.

considering the load you get hauling ~2 tonnes of 4wd around, i think running straight atf is crazy

[B92 8NW]

i know this isnt exactly the answer anyone is looking for, but in the T5 manuals in falcons and commodores, when ford were having issues with baulking shifts when using gear oil, they switched to DEXIII ATF and an additive called lubrizol for the 6cyl's but retained a 75/90 gear oil for the V8's.

considering the load you get hauling ~2 tonnes of 4wd around, i think running straight atf is crazy

I've seen the Lubrizol in penrite guize. http://www.penrite.com.au/files/15YHOQVZLZ/LZ7906.pdf

Got to agree about the load - between the gears hauling 2 tonnes - with hardly any EP additives... plus a little light towing doesn't help.:D

https://www.aulro.com/afvb/images/imported/2009/06/239.jpg

[Blknight.aus]

urm you can call me pedantic......

the autos are shifting the same loads with higher torque inputs and loadings(that torque convertor thingy, takes lots of rpms and converts it to less rpms and more torque yeah...) and they run fine with just ATF as the lubricating oil........

how many times have you seen someone trying to back a trailer or climb something with the engine going bananas and the TC slipping like buggery trying to hold it all in place against the engine....

And you guys are reconing that ATF cant handle it in a Manual thats got a pump in it to make sure everything gets lubed?

(alexs bath time more later)

[Sprint]

urm you can call me pedantic......

the autos are shifting the same loads with higher torque inputs and loadings(that torque convertor thingy, takes lots of rpms and converts it to less rpms and more torque yeah...) and they run fine with just ATF as the lubricating oil........

how many times have you seen someone trying to back a trailer or climb something with the engine going bananas and the TC slipping like buggery trying to hold it all in place against the engine....

And you guys are reconing that ATF cant handle it in a Manual thats got a pump in it to make sure everything gets lubed?

(alexs bath time more later)

i can appreciate what you're saying, and no, i wouldnt expect heat to do much to ATF apart from burn it

what im looking at is ATF's ability to handle metal on metal stress, automatics have little metal on metal stress, only in the bearings, but in the gearsets of a manual gearbox lugging a couple of tonnes of 4x4? i doubt thats the kinda of stresses the industrial chemists were look at when they formulate ATF's

[DEFENDERZOOK]

you heard of planetary gears......?

those little gears which act on them big ones.......im sure theyve got a fair bit of pressure on them.......
and its metal to metal......you will find these in a diff as well......
a diff runs thick gear oil.......

the automatic transmission runs these gears as well......
along with clutches and friction plates.......and all the other methods for destroying oil......

including lots of heat.......and they are designed to run auto oil.........
it is a gear oil.......just a bit thinner.......

there are different types and grades of all oils......
auto oil is just a different grade of gear oil.......




there are better auto oils today than when these gearboxes were designed.......
so maybe running a better quality oil will last longer........
maybe they did get it wrong from the start and should have had gear oil them from the factory........

the only way to know is either by trial and error......or by destructive testing.......

personally.......i would prefer a light gear oil to replace the transmission fluid.......
you can get thinner gear oils today which werent available when those boxes were made.....
must be the closest thing to auto oil........

there are even boxes that ran on engine oil out there......
work that one out........






best thing to do with anything that requires oil or grease.......is to regularly change it.......
so that it has fresh oil or grease all the time.....

it needs to be replaced before it breaks down and loses its lubricating qualities......

this is more important than which oil is used........methinks......

[Blknight.aus]

(more later..... ok so it was the next day)

ok so Defenderzook covered most of the points I was going to make but missed one.

where your ATF type oils do not cut the mustard is situations where you have large gaps to deal with IE diffs, the backlash spacing in the pinion/crownwheel teeth is enough to let the ATF get squeezed out so you wouldnt use it there.

In a manual gearbox thats in good nick ATF is the way to go the tooth to tooth contact (especially in helical cut gears) is such that there isnt enough room for the ATF to escape especially as they are generally submerged at the point of contact. That begins to change as the gearbox wears out as ATF doesnt have as much "cushioning" effect as thicker oils its less able to deal with the additional movement and spaces of a worn box.

Dont mark that as something against ATF fluids by the time your box is worn out enough to make ATF substantially less effective as the primary oil its time to rebuild it back to specs. Yes a gearbox will hang on long beyond this time but your gambling with a few factors including the potential to damage the casing in a manner which renderes it unable to be reused so instead of a rebuild you have the cost of a replacement.

[Sprint]

d'oh, forgot about the planetaries, i still reckon thered be more shear/shock load in a manual box though

*meh* still think its a bad idea running ATF in a manual

[awabbit6]

While the autos still have a gear system, there are 3 planetary gears to share the load. The pressure on the mating surface of each gear is lower so there is no need for a heavy oil in an auto. With a manual, all the load is applied to the gears that are engaged so a thicker oil is required due to the higher pressure at the mating surfaces.
I think that the helical cut on the gears in an auto box is at less of an angle too. If so, this increases the size of the mating surface and also results in less pressure.
The clutches and friction plates are again a large area, so a thick oil isn't required.

Still not sure why LR reccomend ATF in a manual box though :huh:

[rick130]

<snip>

Still not sure why LR reccomend ATF in a manual box though :huh:

because when the oil was specified the only thing available with the required viscosity was ATF or engine oil. There weren't any low vis manual trans fluids.


Lurizol
Regarding Lubrizol, they are one of the biggest additive companies in the world. ie, they are the ones that develop the additive package to meet whatever API or ASEA specs the oil blender wants to meet, then the blender blends those adds into their base oils.
If Ford specced a Lubrizol additive it could be one of hundreds they produce. In other words, Lubrizol is a company, not an additive.

[rick130]

<snip>It almost beggars belief that a good synthetic ATF could cause greater metal wear than a plain ATF, especially after 4,500 kms! I was intending leaving that in for 20,000 as per the manual, by 20,000 it would have been so heavily laden with metal that it would have resembled mercury!




<snip>

it's coincidence, not cause. You've had a component failure that would have occurred regardless of the lubricant used.

[Sprint]

it's coincidence, not cause. You've had a component failure that would have occurred regardless of the lubricant used.

im not 100% convinced the lubricant is without blame

[procrastination inc]

*meh* still think its a bad idea running ATF in a manual...

V8 touring car gearboxes work pretty well with ATF

[slug_burner]

V8 touring car gearboxes probably get rebuilt/serviced a bit more frequently than your average gearbox.

ATF?? Never had gears chewed until it happened in the R380 running ATF. While I was at the gearbox reconditioners the proprietor showed me another R380 which had chewed the gears like in my box. Input gear on first of the gears on the laygear just chewed each other up. During the time I have had the vehicle I have never towed in 5th and when the failure got to the stage I could hear it and feel/smell the heat coming from the box I was not towing either.

I was under the impression that LR no longer recommend ATF for the R380 and that is why the MTF94 was produced by Caltex/Texaco. I would say that this must say a lot for the ATF argument.

I took the following snippet from the difflock forum

http://http://forum.difflock.com/viewtopic.php't=17098&highlight=mtf94

"ATF was originally specified for the LT77 5-speed gearbox and, theoretically, could be used in the later R380 box. Type DIII is the best grade currently available. ATF was originally specified because of the weak synchromesh in the LT77 and R380 boxes (especially second gear).

ATF has a very low viscosity (rated as 5W20 since it falls below normal gear oil viscosity grades) and so it has minimal drag on the gears, enabling the weak synchromesh to do the best of a bad job.

BUT ATF has several drawbacks which is why it is NO LONGER recommended for use in such boxes. These are:

It is generally a plain mineral base stock formulation (even DIII) and this, coupled to its very low viscosity, means that it is poor at preventing metal to metal wear in manual transmissions.

This is compounded by the fact that the viscosity improvers within (thickeners) are more rapidly sheared down in manual transmissions. Again, this reduces the protective film strength of the ATF in those areas of high pressure contact and also increases transmission noise. "

Joel,

Stick with the synthetic, your gearbox has failed and like someone else said it is a coincidence that it failed at a time when you changed gear oil type.

[rick130]

im not 100% convinced the lubricant is without blame

He's run ATF for 305,000km. All Joel has done is changed the type of ATF to one with a higher load and temperature rating. (Transmax Z meets GL-4 specs, although it isn't on the Oz spec sheet)
How has the fluid contributed to the failure ?