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 bantula |
Hot Gearbox |
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Registered Member
Posts: 164 Tue, 8-May-2007 07:20 |
Hi all, it seems that when the G/box gets warm/hot I find it hard to select 1st or reverse or even to get 1st when at a stand still. Has anyone else had this problem or has anyone got an idea of what the problem might be.
Thanks bantula |
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HYDRAULIC1 |
Re: Hot Gearbox | #1 | ||
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Registered Member
Posts: 130 Wed, 9-May-2007 20:53 |
i have had a similar problem, with other cars where the gearbox oil gets thin when the temp rises, this breaks down the additives and lubrication of the oil, and when cold the viscosity is back to nearly normal, i would check the gearbox
oil level and the level it may be that it needs replacement for a thicker viscosity, it may be worth try and could be a cheap resolve rgds steve hydraulic1 |
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bantula |
Re: Hot Gearbox | #2 | ||
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Registered Member
Posts: 164 Thu, 10-May-2007 07:02 |
Thanks for that. I will have a look this w/end. I really want to get it sorted before the Marcos w/end, end of June.
Cheers bantula |
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Major Bloodnock |
Re: Hot Gearbox | #3 | ||
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Registered Member
Posts: 324 Thu, 8-Nov-2007 10:50 |
I was always told to use automatic transmission fluid in my gearbox. Assuming you have the standard 5 speed rover box.Copes with the temperature changes much better. Well I never had a problem in that department anyways.
Si Via Dificlis Sit. Hanc Eligam!
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Pep |
Don't use ATF! | #4 | ||
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Registered Member
Posts: 9 Sat, 10-Nov-2007 22:15 |
Gents,
ATF was originally recommeded for use with the LT77 by British Leyland from the early 80's onwards because people were struggling to change gear when the gearbox was cold and in cold ambient conditions with normal gear oil (EP80). They introduced ATF to cure the problem but it doesn't do the box any favours regarding wear. There are plenty of forums on the web discussing this topic. I used to use Castrol SMX-S which is much more stable under varing temperature conditions and also gives gives better protection. |
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martineztop |
Re: Don't use ATF! | #5 | ||
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Registered Member
Posts: 1428 Sat, 10-Nov-2007 23:36 Chief mechanic |
I agree with Pep, I'd go for a semi sythetic multigrade gear oil, bought some recently for a type9 box, ATF may be ok for some newer boxes, but those gears and bearings won't like it
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sandyv8 |
Hot Gearbox | #6 | ||
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Registered Member
Posts: 29 Wed, 12-Mar-2008 10:51 |
Many Thanks Good People,for providing this info.
I have just had this happen with mine,no problem while out on the road, but when I came to move it a short while after returning home. sandv8 |
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martineztop |
#7 | |||
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Registered Member
Posts: 927 Wed, 12-Mar-2008 10:59 Chief mechanic |
it can also be the clutch getting hot and binding
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sandyv8 |
Hot Gearbox | #8 | ||
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Registered Member
Posts: 30 Wed, 12-Mar-2008 13:29 |
Hi martineztop,
The resistance was in the gear-lever movement as though the mechanism had no lube due to the heat,shall change gearbox oil and see what amount of oil is in presently, hoping it is not in the clutch , I would think that with the recent work done on vehicle that all in that area was ok,still no guarantees. sandyv8 |
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Jack |
#9 | |||
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Registered Member
Posts: 1191 Wed, 12-Mar-2008 14:36 Guru mechanic |
When a gearbox is fighting back a simple trick to engage first gear is to engage second before engaging first - no need to lift the clutch - it appears to line
up the gears to make the shift into first much easier.
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marcos3lv6 |
Hot Gearbox | #10 | ||
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Registered Member
Posts: 13 Fri, 14-Mar-2008 13:08 |
Firstly why do you think the gearbox is HOT. All the mechanical bits in a MARCOS always run HOT ( usually too hot ).
I had / still have, but not so much, the same problem i.e. difficult to get first and reverse, Does it Crunch when selecting reverse? Problem is not with gearbox it is the CLUTCH not working properly. This is both experience and comments for two different gearbox specialists. Both said, after I had given symptoms, its not the gearbox its the clutch, and neither would even look at the gearbox afterwards. Apparently the crunch in reverse is the clincher. A lot of cleaning, refitting and changing clutch bits has helped but still not perfect. |
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martineztop |
#11 | |||
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Registered Member
Posts: 934 Fri, 14-Mar-2008 16:51 Chief mechanic |
does anybody do a clutch cooler?
I used to have same problem with mine if stuck in traffic, it also used to judder when you tried to pull away slowly |
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sandyv8 |
Hot Gearbox | #12 | ||
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Registered Member
Posts: 31 Fri, 14-Mar-2008 20:20 |
It`s good hear what others have experienced in this department and many thanks for the input.
Well yesterday decided to get the car up in the air and check out what gear-oil was in the box.The magnetic drain-plug was like a xmas tree virtualy impossible to have collected any more on it.The oil was very watery in appearance and black in colour,obviously not been changed for a long time. I am replacing with a 75/90 Semi-synthetic. While under the car I was looking at the engine sump and noticed that the drain plug on that was at the rear with not a lot of space between that and the flywheel. Now if this plug is removed surely the oil will spurt back contaminating the clutch. There is no cover plate on the bellhousing, is this the norm ? sandyv8 |
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martineztop |
#13 | |||
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Registered Member
Posts: 935 Fri, 14-Mar-2008 22:47 Chief mechanic |
75/90 is a good choice I think for older boxes, if there's that much loose metal in there I'd suspect something's worn badly, sorry to p*ss on your
parade mate. having no cover is not an issue as long as you don't mind all the crud getting into the clutch and making a mess. road salt is really good for
clutches along with grit, chewing gum and the odd dead cat
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sandyv8 |
Hot Gearbox | #14 | ||
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Registered Member
Posts: 32 Sat, 15-Mar-2008 10:00 |
Hi Martin,
Its not my parade that your are urinating on, its the unbelievable shortcomings of previous so called mechanics. Obviously has you point out being open to the elements is not good so will be rectified.(anyone know to one,save trawling the scrapyards ?) In reply to marcos3lv6 the gear selection had never been a problem prior to the day in question no crunching on engagement and the clutch as a good feel to it. If I had parked the car and left it to cool before using this would have gone unnoticed. Whoever made the engine sump I feel could have positioned the drain plug to the side,as underneath probably susceptable to grounding. sandyv8 |
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CF Mantula |
#15 | |||
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Posts: 1396 Mon, 17-Mar-2008 07:43 Minor mechanic deity |
Hi sandyV8,
should not be a problem to find a engine sump with drain plug fitted to the side - Ebay -. From my own experience you will quite often touch the ground with the sump. We weld to every Marcos - not only V8´s - a massive metal plate like a ski under the sump. And if you have a look to this plate now after around 85.000 km it was one of the best investments to the Mantula. I think otherwise I would have at least one new engine. By the way the drain plug should be fitted to the side in the way that you will open it against the driving direction, otherwise it is possible the moment you touch the ground the plug will be opened and you loose very quick with some vibrations the motor oil. I know 2 V8´s where this happened in the meantime twice. My drain plug has to be renewed next time changing oil, because the bolt is rubbered down to the height of the sump protection and it becomes more & more difficult to open it with the tool. CF Mantula |
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sandyv8 |
hot gearbox | #16 | ||
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Registered Member
Posts: 38 Sat, 22-Mar-2008 15:54 |
Hi CF Mantula
Have decided to retain the sump as is,already have the ski plate as you describe and the sump is of sturdy construction. I will fabricate a cover plate from alloy ,which will be removed and replaced with polythene when draining engine oil. This will allow room to remove plug and protect the clutch. sandyv8 |
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CF Mantula |
#17 | |||
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Registered Member
Posts: 1400 Sun, 23-Mar-2008 18:34 Minor mechanic deity |
Hi SandyV8,
never had a problem with hot gearbox, clutch, etc. and drive around 30.000 km per year on motorway, town, traffic and the old Nürburgring. The live axle becomes very hot and if driving the "Ring" the temperatures rise to nearly 130 degree. It is not the only Mantula live axle with this problem. We will try now other oil and as well fit a rear plate to the diff with rips like Ford used on the World Rallye Cars. Hope this will help and cool down enough. The idea with alloy cover plate seems to be good and especially the polythene is a good idea. Would like to see some pictures if the job is finished. CF Mantula
Last Edited By: CF Mantula Sun, 23-Mar-2008 18:38.
Edited 1 time.
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OldNoccer |
Cooling diff oil | #18 | ||
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Registered Member
Posts: 210 Sun, 13-Apr-2008 20:16 |
I noticed some of the Yankee cars at Goodwood had propshaft driven oil pumps next to the rear axle, presumably to pump the diff oil through an oil cooler.
I am no racing expert, maybe that is common for classic racers. I don't normally look underneath, but this one was jacked up. Steve
There's a lot of talk these days about green transport. Well, I am ahead of the game, I already have green transport ... British racing green.
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martineztop |
#19 | |||
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Registered Member
Posts: 975 Mon, 14-Apr-2008 08:56 Chief mechanic |
Yes, a lot of performance cars with LSD have oil coolers fitted to the Diff, it gets a real pounding on a track and the LSD slippage causes even more heat
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