Strange gearbox/clutch problem (V8/LT77)
Discussion
The thing about the cleansing process one devised, using a mix of white spirit and ATF to flush the box, was, the 'last chance saloon' decision had already been made, and if the problem could not be fixed that-away, then it was gonna be "bye,bye blackbird". It was that bad.
With another vote for Mobil 1 from carsy, one still has a sneaky feeling that the combination of that oil with the moly g/box treatment was the clincher.
If carsy did not use the molyslip product, it sure would be a useful bit of data to find out if it further improves his gear box.
If a box is otherwise unusable one has virtually nothing to lose except twenty quid on oil and stuff, to find out if it has to be repaired/replaced and if you think about it, one could filter the new fluid later extracted and reuse it, it dont exactly wear out.
With another vote for Mobil 1 from carsy, one still has a sneaky feeling that the combination of that oil with the moly g/box treatment was the clincher.
If carsy did not use the molyslip product, it sure would be a useful bit of data to find out if it further improves his gear box.
If a box is otherwise unusable one has virtually nothing to lose except twenty quid on oil and stuff, to find out if it has to be repaired/replaced and if you think about it, one could filter the new fluid later extracted and reuse it, it dont exactly wear out.
I have filtered my previous change of SMX-S for re-use, although I was slightly worried that the micron-sized particles wouldn't be filtered out.
I suppose doing this and changing on a regular basis is much better than leaving it in which is what most people do (and top up occasionally).
Is the moly in black axle grease the same stuff as what you get in Molyslip etc?
I suppose doing this and changing on a regular basis is much better than leaving it in which is what most people do (and top up occasionally).
Is the moly in black axle grease the same stuff as what you get in Molyslip etc?
This is the stuff I use, half the tube in the gearbox and the other half in the diff.
The diff fluid has never been changed since to original treatment in 1996, just topped up from time to time, but the gearbox is drained and refilled/re-dosed with moly every 3 to 4 years.
On every occasion since 1996 the amount of shlitty deposits/stuff seen in the box was virtually nil so never deemed it necessary to repeat the flushing process. They simply stopped appearing.
On my last change, I just instructed my local garage to drain and refill with the fluids/treatment that I provided - its a hatred of cold concrete thing, combined with old age.
Dunno about any other axle treatment, except that molybdemum disulphide is a generic treatment that will be used by many different suppliers in their various applications.
Its properties, I believe, are that it attaches itself to metal parts but has a low friction coefficient to itself.
For that reason, I'm told, Moly should not be introduced into new or rebuilt engines until after they have been run-in, because of the low friction, the parts never get bedded properly.
Someone will probably know more about the science, my interest was limited to getting a result.
The diff fluid has never been changed since to original treatment in 1996, just topped up from time to time, but the gearbox is drained and refilled/re-dosed with moly every 3 to 4 years.
On every occasion since 1996 the amount of shlitty deposits/stuff seen in the box was virtually nil so never deemed it necessary to repeat the flushing process. They simply stopped appearing.
On my last change, I just instructed my local garage to drain and refill with the fluids/treatment that I provided - its a hatred of cold concrete thing, combined with old age.
Dunno about any other axle treatment, except that molybdemum disulphide is a generic treatment that will be used by many different suppliers in their various applications.
Its properties, I believe, are that it attaches itself to metal parts but has a low friction coefficient to itself.
For that reason, I'm told, Moly should not be introduced into new or rebuilt engines until after they have been run-in, because of the low friction, the parts never get bedded properly.
Someone will probably know more about the science, my interest was limited to getting a result.
GV said:
There's a Mobil 1 Gear oil too. Which Mobil 1 should be used - I take it we're talking about Mobil 1 engine oil for the gearbox?
Yes! According to a web search, the Mobil 1 gear oil seems to be 75W-90 or 140 and is recommended for heavy duty transmissions.My original choice mentioned in earlier passages on this thread - ie:
• The box was then refilled with 5W40 "Castrol RS" (0W40 "Mobil 1" is virtually the same and I have subsequently used both with no discernable difference).
was the very thinnest synthetic engine oil generally available and based upon an informed recommendation from a Mobil employee.
Strangely, if my box had otherwise croaked in 1996, this subsequently successful solution would probably have died with it.
Interesting observation I have made today. By accident I cam across some Esso semi synthetic oil rated at 0W40 in my stockpile of Wedge bits which was compared to the MTL-Redline I stuck in my gearbox. What came to light was how thick the 0W40 compared to the Redline which was like water in comparison.
The next opportunity will see a prompt change of oils along with the molyslip going in. Despite the re-build which has only seen a handful of miles the gear change is quite notchy...I'll let you know the results.
The next opportunity will see a prompt change of oils along with the molyslip going in. Despite the re-build which has only seen a handful of miles the gear change is quite notchy...I'll let you know the results.
Well in the mean time I have put the clutch back together. The new master is off - it seems to have a reservoir/pistorn end seal that only breaks open when the cluch is let open extremely quickly. If you let off at a normal rate it won't open to the reservoir. The end rubber seems much deeper than usual and consequently is sealing off the reservoir almost all the time.
So I shimmed out the end washer on the original master with a couple of small washers and put it back together, it bled straight away and is operating smoothly again.
Now for the gearbox - well on a short drive there were a few notchy moments but it seemed generally OK. Hopefully the oil top-up has helped a bit, but time will tell on a longer drive. If all else fails it's the white spirit treatment and a few litres of Mobil 1 or Castrol.
So I shimmed out the end washer on the original master with a couple of small washers and put it back together, it bled straight away and is operating smoothly again.
Now for the gearbox - well on a short drive there were a few notchy moments but it seemed generally OK. Hopefully the oil top-up has helped a bit, but time will tell on a longer drive. If all else fails it's the white spirit treatment and a few litres of Mobil 1 or Castrol.
OK on a 20-mile drive the same problems resurfaced so it looks like the flushing treatment.
For a refill Castrol seem to do this stuff now in 0W/40:
Edge Sport 0w/40 1 litre For high performance and modified modern 14.99
Edge Sport 0w/40 4 litre vehicles fully synthetic sports performance 46.15
Is this the same stuff as RS (or has supercedded it?)
Mobil 1 0W40 seems easy enough to come by.
For a refill Castrol seem to do this stuff now in 0W/40:
Edge Sport 0w/40 1 litre For high performance and modified modern 14.99
Edge Sport 0w/40 4 litre vehicles fully synthetic sports performance 46.15
Is this the same stuff as RS (or has supercedded it?)
Mobil 1 0W40 seems easy enough to come by.
Adam, I think the bottom line, after the flush, is the type, viscosity and the recipe.
So for me it was a fully synthetic 0W40 or 5W40 - with moly, and remember it was 1996 and an experiment/crisis decision that worked with either Castrol RS or Mobil 1 being my (somewhat) restricted choice.
Since then a lot or folks have tried my recipe and it worked, just like it has worked splendidly for me since 1996.
More recently, there has been interest in Redline MTL, specifically formulated for this type of gearbox. So people have been trying that too.
The Redline MTL Technical Information leaflet can be printed off, double-sided, onto an A4 sheet and you get a handy three fold leaflet here.
http://www.vintagemodelairplane.com/pages/Download...
I have had no feedback from Redline users, the same as some of the other variants that get mentioned in the forums or the pub.
So when a person is in a quandrey "what shall I use?" - it becomes a simple choice of - who you believe and what seems to make sense.
What is clear however, there is no adverse feedback from people who decided to ditch ATF and went over to something else PLUS the moly.
So for me it was a fully synthetic 0W40 or 5W40 - with moly, and remember it was 1996 and an experiment/crisis decision that worked with either Castrol RS or Mobil 1 being my (somewhat) restricted choice.
Since then a lot or folks have tried my recipe and it worked, just like it has worked splendidly for me since 1996.
More recently, there has been interest in Redline MTL, specifically formulated for this type of gearbox. So people have been trying that too.
The Redline MTL Technical Information leaflet can be printed off, double-sided, onto an A4 sheet and you get a handy three fold leaflet here.
http://www.vintagemodelairplane.com/pages/Download...
I have had no feedback from Redline users, the same as some of the other variants that get mentioned in the forums or the pub.
So when a person is in a quandrey "what shall I use?" - it becomes a simple choice of - who you believe and what seems to make sense.
What is clear however, there is no adverse feedback from people who decided to ditch ATF and went over to something else PLUS the moly.
honestjohntoo said:
Adam, I think the bottom line, after the flush, is the type, viscosity and the recipe.
So for me it was a fully synthetic 0W40 or 5W40 - with moly, and remember it was 1996 and an experiment/crisis decision that worked with either Castrol RS or Mobil 1 being my (somewhat) restricted choice.
Since then a lot or folks have tried my recipe and it worked, just like it has worked splendidly for me since 1996.
More recently, there has been interest in Redline MTL, specifically formulated for this type of gearbox. So people have been trying that too.
The Redline MTL Technical Information leaflet can be printed off, double-sided, onto an A4 sheet and you get a handy three fold leaflet here.
http://www.vintagemodelairplane.com/pages/Download...
I have had no feedback from Redline users, the same as some of the other variants, such as SMX - S, that get mentioned in the forums or the pub.
So when a person is in a quandrey "what shall I use?" - it becomes a simple choice of - who you believe and what seems to make sense.
What is clear however, there is no adverse feedback from people who decided to ditch ATF and went over to something else PLUS the moly.
So for me it was a fully synthetic 0W40 or 5W40 - with moly, and remember it was 1996 and an experiment/crisis decision that worked with either Castrol RS or Mobil 1 being my (somewhat) restricted choice.
Since then a lot or folks have tried my recipe and it worked, just like it has worked splendidly for me since 1996.
More recently, there has been interest in Redline MTL, specifically formulated for this type of gearbox. So people have been trying that too.
The Redline MTL Technical Information leaflet can be printed off, double-sided, onto an A4 sheet and you get a handy three fold leaflet here.
http://www.vintagemodelairplane.com/pages/Download...
I have had no feedback from Redline users, the same as some of the other variants, such as SMX - S, that get mentioned in the forums or the pub.
So when a person is in a quandrey "what shall I use?" - it becomes a simple choice of - who you believe and what seems to make sense.
What is clear however, there is no adverse feedback from people who decided to ditch ATF and went over to something else PLUS the moly.
Whats the problem with your box Andrew. I had mine rebuilt, allbeit on a Griff, but i`m not happy with the 1st to 2nd change. Its not notchy as they can be renowned for, it goes straight in but with a bit of a grate as if the synchro is bad. If the box is hot after a good run this grating is gone. 3rd to 2nd is perfect whatever temp as all the other changes are.
This is the reason why i experimented with ATF, Castrol smx and then the Mobil 1. to see if any would help with that 1st to 2nd slight crunch. The Castrol went in first and felt good bar this grate 1st to 2nd. Then tried atf. Everything felt dreadful, it was like i could feel metal on metal every change. This came straight out and then the Mobil 1 0w40 and Moly. The Mobil isnt too far from the SMX but i think the Mobil gives a smoother better change and that is what i am sticking with for now.
Would just like to sort the cold 1st to 2nd crunch but i am now out of ideas. Maybe the syncro is just a bad one despite being new. See how this summer goes then it may have to come out again.
This is the reason why i experimented with ATF, Castrol smx and then the Mobil 1. to see if any would help with that 1st to 2nd slight crunch. The Castrol went in first and felt good bar this grate 1st to 2nd. Then tried atf. Everything felt dreadful, it was like i could feel metal on metal every change. This came straight out and then the Mobil 1 0w40 and Moly. The Mobil isnt too far from the SMX but i think the Mobil gives a smoother better change and that is what i am sticking with for now.
Would just like to sort the cold 1st to 2nd crunch but i am now out of ideas. Maybe the syncro is just a bad one despite being new. See how this summer goes then it may have to come out again.
GV said:
I am using Red Line MTL and as yet I'm not entirely satisfied especially on a newly rebuilt 'box.
As more anecdotal evidence emerges (and bearing in mind that I home-in on any LT77 lube story over 6 or 7 forums) it seems more and more tales just like the above experience come to light.That is, ditching ATF generally brings an improvement, but adding molyslip gearbox treatment makes things even better.
The dilemma would be, with a rebuilt gearboxbox, how soon after putting it back into service would one choose to introduce the slippery additive.
My personal view would be that a rebuilt LT77 gearbox is not like a rebuilt engine where the tolerances are more critical, so introducing molyslip to the gearbox, at any stage, would always be beneficial.
The final insult, however, is that sometime or other, after re-lubing, a box will croak anyway, and in truth, there is no way of predicting it is gonna happen, so the re-lube get the blame, perhaps unjustly.
With hardly any LT77 owner/enthusiast being part of a Formula 1 racing team, with oodles of analytical back-up, following one's best hunch is probably the good bet.
[quote=carsy]Whats the problem with your box Andrew.
Before the rebuild I had no troubles with engaging any of the forward gears ironically enough - reverse was ok when the box was warm. I had the rebuild done because the the flange seal was leaking dripping oil over the exhaust plus the inner speedo drive was shot. When I drained the oil it looked like weak tea!
Presently 1st & 3rd gear is quite notchy and difficult to engage - reverse is difficult and requires a shove.
Before I go back to the people who rebuilt it I want to try Mobil & Moly. They recomend using ATF and want to test drive the car. I will make the lube change on Friday. Let's see what happens.
Before the rebuild I had no troubles with engaging any of the forward gears ironically enough - reverse was ok when the box was warm. I had the rebuild done because the the flange seal was leaking dripping oil over the exhaust plus the inner speedo drive was shot. When I drained the oil it looked like weak tea!
Presently 1st & 3rd gear is quite notchy and difficult to engage - reverse is difficult and requires a shove.
Before I go back to the people who rebuilt it I want to try Mobil & Moly. They recomend using ATF and want to test drive the car. I will make the lube change on Friday. Let's see what happens.
My lube change is imminent - 40 quids worth of Mobil 1 purchased (less halfrauds staff discount - mates rates) should be enought for 2 changes over the years.
Strangely Halfrauds didn't have the green molyslip in (despite showing it in stock online) but I may have half a tube in the barn.
White spirit and ATF for flushing - I have a plenty.
Strangely Halfrauds didn't have the green molyslip in (despite showing it in stock online) but I may have half a tube in the barn.
White spirit and ATF for flushing - I have a plenty.
Popped into the bike shop and picked up 2ltrs of Mobil 1 & a tube of Molyslip. I'm doing the lube change tomorrow weather permitting. I'm not intending to flush the box as it is still newly re-built although that's dependent on the shade of red that comes out.
My 60 mile round trip to GAZ in order to fix the SH coilover problem wasn't too bad although getting into reverse was awkward. Let's hope tomorrow solves the problem....we'll see.
My 60 mile round trip to GAZ in order to fix the SH coilover problem wasn't too bad although getting into reverse was awkward. Let's hope tomorrow solves the problem....we'll see.
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