LT77 hard to get into gear- any ideas?

[conrod]

I have recently bought a 1995 LDV 400 van with a RV8 and LT77 box. It has only done 30000mls from new. Since picking it up it has been hard to get into first gear or reverse from a standstill. At best it might go in with a small clunk, at worst you get the big grinding noise. Going up and down through the gears is not bad, but not brilliant either.

I thought it was the clutch not releasing properly, and yesterday dropped the box off for a look. The clutch had seen quite a bit of heat, lots of hotspots on the cover and some on the flywheel too, and the clutch plate looked like it had seen better days. So I surfaced the flywheel, fitted a new clutch,cleaned input shaft spline, oiled the spigot bearing, box back in, and its still the same!

Is this common for these gearboxes? Or do I still have a clutch problem? Trying to diagnose the problem without throwing parts at it unnecessarily. (needed a clutch anyway, so not a biggie there) Should I dump the oil and try something different in it? Any suggestions would be appreciated.

Conrad

[unstable load]

Dump the LT77 and fit the later model box (R380?).

[conrod]

sorry but that is not very helpful.
I do not know if the gearbox is definitely the fault, which is why I was asking for input from others as to whether this problem is common with the LT77. And an R380 will be impossible to find here.

Conrad

[DaveEFI]

sorry but that is not very helpful.
I do not know if the gearbox is definitely the fault, which is why I was asking for input from others as to whether this problem is common with the LT77. And an R380 will be impossible to find here.

Conrad

Reverse is the obvious one to check with since it has no synchromesh to mask the noise of gears trying to mesh.

If you fully depress the clutch at idle then move the lever gently towards the reverse position it should be very obvious by the crunching noises if the gearbox layshaft is still turning.

If the new clutch is to the correct spec and fitted correctly, the fault must then be somewhere in the release mechanism.

[conrod]

thanks Dave,

I did not know if it had synchromesh on reverse or not. Reverse will give you a crunch usually, and first is very hard to select, like you are trying to get it in gear without depressing the clutch. From your description I would say the layshaft is still turning. Possibly still a fault with the release mechanism, or something else causing the clutch to drag?

Conrad

[ian.stewart]

Assuming you are still hydraulic, Push the slave cylinder fully home, now pull the clutch arm gently away from the cylinder, there should be about 3mm free play in the push rod, more, It could be your pushrod is too short,
if everything checks out, your master cylinder may not be big enough to provide enough fluid to disengage the clutch fully

[conrod]

thanks Ian,
yes clutch is hydraulic, all OEM parts. But that is exactly the feeling I am getting, as if something is jammed under the pedal not allowing enough travel in the clutch arm, or as you say m/cyl sizing or pushrod issues. I will remove the lower bellhousing shield and have abit of an inspection with someone pushing the pedal down. Listening to all your guys advice, I am sure the issue is in this area. Cheers!

Conrad

now back to the world cup. 0-0 at half time with Paraguay, we need to score!

[ramon alban]

Hello Conrad,

Here is a updated extract from a PDF on my website. The lubricant in mine has been doin' its stuff for over a decade with never a sign of the original problems.

Radical Cure for a Nasty 5 Speed Manual Gearbox

• Here is a radical solution to an unfriendly 5-speed gearbox. My Vitesse used to have a truly nasty gearbox. It baulked at will and was notchy to a fault. In fact it was very, very hard work. This was my last resort.

• During a routine gearbox oil level check, I noticed how dirty the lubricant had become so it was obvious it had to be flushed and changed. It had the recommended ATF which Rover had been forced to specify, because the gearbox was unreliable when filled with conventional lubricant.

• By coincidence, I had been told by an Ex-Mobil employee that Mobil 1 or Castrol RS at 0W40 or 5W40 viscosity were considered by the trade to be a better replacement than ATF in the Rover 5 speed box and gave a much improved performance.

• With the car on axle stands and the back wheels off the ground I drained the box and re-filled it with a flushing mixture of 2:1 white spirit and ATF (I did say radical and it was a last resort!).

• With the engine running at idle speed only, I put the car through all the gears and let the drive train run off-load for 5 to 10 minutes.

• Upon draining the flushing mixture I was amazed at the filthy color and state of the drained fluid. It was as black as ebony with lots of sediment!

• I repeated the above with a clean batch of mixture to flush out the residues. One can imagine the washing machine action inside the box allowed the solvent component to reach into every recess.

• 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).

• I then added a recommended dose of Molyslip Gearbox Treatment. This stuff comes in a tube-like applicator and is available from Halfords, etc.

• The transformation was miraculous. It has run for over 14 years without any of the original symptoms and is a total pleasure to use.

• The oil has been replaced four times in that period with Mobil 1 or Castrol RS and the same Molyslip gearbox additive each time.

There is more gearbox stuff here:

http://www.vintagemodelairplane.com/pag ... box01.html

[conrod]

Thanks Ramon,
I just read that off your site yesterday! I will probably do a flush and oil change as you described, regardless of what the outcome of this issue is.
Cheers Conrad

[DaveEFI]

Ramon, I wonder what was in your box before you drained and flushed it? Some form of magical additive? Manual gearbox oil doesn't normally change colour much - and ATF only does so in an auto box where the friction linings are breaking up.

[ramon alban]

Ramon, I wonder what was in your box before you drained and flushed it? Some form of magical additive? Manual gearbox oil doesn't normally change colour much - and ATF only does so in an auto box where the friction linings are breaking up.

Dave, I missed this query way back in June!

During the early part of my ownership the box was drained/refilled with ATF, but not flushed.

A few years later when I decided to check/change it again, it was clearly comtaminated because its colour was unlike the fresh red stuff I'd put in, darker but not black.

The black silt within, however was loose and slimey and Ive no doubt that after a journey it would have be in suspension, as a result of the washing machine-like action, so when I warmed up the box on a run and drained it straight away the colour was very dark indeed.

I imagine even when using specified fluid, if one checks its condition on a cold box, the colour would appear more original after the sediment has re-settled?

[5000SE]

Ramon's post above is spot-on (and I think he may have been referring to chats we had on the SD1 Club forum).

Rover's reason for putting ATF in the gearbox was simply because they got it wrong in the first place when the box was built. It had a horrible clunky change when cold with normal oils - filling with ATF allowed them to get round the problem, and they knew that gearbox life would still be ok (ish) with ATF fill, as gearboxes will tolerate such a wide range of oils.

The advent of synthetic engine oils changed things. Their flatter viscosity index means they're so much thinner when cold, so those clunky arse-clenching cold changes are a thing of the past when an LT77 is filled with Mobil 1 or equivalent.

To be honest, the same applies to most gearboxes. We need special gear additives for hypoid differentials but few automotive gearboxes need anything but good quality base stock oil.
Engine oil is just as good as gear oil for that, and a synthetic oil will greatly increase the life of the box.

[DaveEFI]

Ramon, I wonder what was in your box before you drained and flushed it? Some form of magical additive? Manual gearbox oil doesn't normally change colour much - and ATF only does so in an auto box where the friction linings are breaking up.

Dave, I missed this query way back in June!

During the early part of my ownership the box was drained/refilled with ATF, but not flushed.

A few years later when I decided to check/change it again, it was clearly comtaminated because its colour was unlike the fresh red stuff I'd put in, darker but not black.

The black silt within, however was loose and slimey and Ive no doubt that after a journey it would have be in suspension, as a result of the washing machine-like action, so when I warmed up the box on a run and drained it straight away the colour was very dark indeed.

I imagine even when using specified fluid, if one checks its condition on a cold box, the colour would appear more original after the sediment has re-settled?

Perhaps it was some form of reaction between the original oil and ATF?
There's nothing in a manual box which can cause a black sludge - not like an engine, or an auto with the clutch linings breaking up. The worst you should fine is metal particles from grinding gears. And hopefully stuck to a magnetic sump plug.

I'd guess a previous owner had used some snake oil in an attempt to make the change better.