could it be clutch? fly wheel

 

surely the clutch or flywheel would affect all gears?

Although yeah it could be the clutch/flywheel/rear oil seal causing the judder, although I am wondering if it's possibly something else that could be linked to the 2nd gear problem.

 

Drain the PG1 gearbox of lubricant and measure it. I pour it into a clean empty plastic milk bottle with the measure index of pints/litres on it. You should see close to 2 litres of MTF 94 in the drain bowl. If less than that is drained, then your box has been running low on lubricant so some components will suffer from insufficient lubricant. First things to suffer are the Synchro mechanisms and Differential Bearings when lubricant runs low. 2nd gear selection often suffers first on gearboxes, not just Rovers and MGs. Fords and other in my experience ... :dunno: why ..

When lubricant runs really low, you can get toothless constant mesh clusters. Two PG1s on Rover Turbos I know lost all teeth on meshed pinions of Top and 4th gears. I drained one eggcup full of lubricant from this PG1 toothless wonder Gearbox. There should be 2.2 litres! :~



Another PG1 Turbo box also lost teeth on 4th and 5th. That car, a 220 Coupe turbo I bought from the previous owner came with a wodge of expensive Invoices including one for £800 for a gearbox rebuild less than a year previously. He sold the car after being suspended for being clocked @ 133 mph on the M3. There was NO lubricant at all in that 'dry' gearbox!

No bluddy wonder.

Moral, wise to check your gearbox lubricant levels in the way described above particularly on a used car bought recently. They must be treated as unknown quantities ~ hey nearly a pun. If there is the correct quantity drained and it looks OK, put it back. At least your know it's got the required amount. I do that now as twice bitten .... or summut ...

 

I did check the level through taking out the filler plug and a little oil come out with the plug removed.

Should I still remove the oil and check the amount? if so I'll try and get on that tomorrow.

I know the oil was changed with the correct MTF 94 just before I got the vehicle and I have the remainder of a 1 litre bottle, so if it is low I should be able to top it up.

 

Should I still remove the oil and check the amount? if so I'll try and get on that tomorrow.

I know the oil was changed with the correct MTF 94 just before I got the vehicle and I have the remainder of a 1 litre bottle, so if it is low I should be able to top it up.

I would check it anyway. Even if only 25% Oil is present, that still gets flung around by the Crownwheel so a little escaping from the Filler Plug when it is removed can be misleading as well as accurate. When I remove the filler plug in a box that I know is fully filled, more than a trickle usually comes out.

1 litre bottle ? Was that used to top up of fill the box ? 2.2 Litres of MTF 94 is recommended.

Just thought I should add, when I said it wouldn't go into second, the gear level will not pull back at all it's like it's jammed.

Now that sounds far more serious unfortunately. Can you select 2nd gear from neutral, 1st or 3rd with the engine switched off with the clutch pedal to the floor ?

 

Just thought I should add, when I said it wouldn't go into second, the gear level will not pull back at all it's like it's jammed.

 

If it turns out that you have the correct amount of lubricant then try and completely replace the old lubricant with brand new fresh mtf94.

 

Your gearbox lubricant check shows all's well. Colour and quantity fine.

The fact that you are able to select all gears OK with engine switched off, could, repeat could indicate that the slave cylinder is not fully releasing the clutch as it should. Check the fluid level and condition of the fluid in the hydraulic reservoir. If it is low and blackish rather than clear, that is not what you want to see. Low level means fluid being lost and blackish indicates the rubber seals have lost many minute particles and is worn. Watch the crank on the Bell Housing whilst someone presses the clutch pedal to the floor in the car. There should be a good range of positive movement.

Then, if the clutch release hydraulic system all completes checks in good shape, the problem lies elsewhere. IIRC, the 2nd gear selection problems occurred prior to fitting the modified gear control shaft ? So, the modified shaft is not the cause. Then, can only assume the problem lies within the actual gearbox.

One other possibility occurs to me. A worn or wearing clutch component.

Please keep in mind all the above is remote guesswork. Without trying the car and being in possession of all the facts, hard to be certain. Even with those facts, still could be hard to ID the problem.

 

It usually goes a bit dark after a while but the carlube MTF94 that I use is golden. The reason I suggested refreshing the oil is that my differential used to moan and make a grinding noise, only after about 15 to 20 minutes of driving when the oil was hot, when turning into tight corners. It never did it when the oil was cold which made me believe it was something to do with the fluid. I bought new carlube MTF94, drained away all the old fluid and filled the box with the new fluid. The noise went away completely.

The other reason is you could have a slightly dragging clutch, as MGJohn has already suggested, i.e. it doesn't completely disengage thus making gear changes difficult.

 

Will check the clutch fluid. Tbh clutch problems never really occurred to me as it's only the downshift to 2nd. Will report back once I've checked.

 

2nd gear synchro usually is under more stress, during downshift, more than the other gears as the speed differential is usually great, i.e, when you are slowing down, you go straight from 5th or 4 th to 2nd and any dragging of the clutch will cause problems. It is also usually the synchro that wears first due to the above reasons. Lets hope it is not the synchro.

 

Denis had confirmed my observations about 2nd gear in my post #4. :~

.
2nd gear selection often suffers first on gearboxes, not just Rovers and MGs. Fords and other in my experience ... :dunno: why ..

I now know why .. .. although I had suspected the reason. My very first MG, an MGB back in the 1960s had a baulky 2nd gear once it had accumulated a good few miles. Also my Ford Escort Company car was impossible to select 2nd gear from 3rd or higher. That did not have many miles on it.

 

Denis, soon after learning that the oil in the PG1 Gearbox is designed to last the life of the car, I found that hard to believe. Then, when out of curiosity I drained the oil in the car's PG1 in my wife's 1990 1.6 LX Montego which we had for thirteen years, I was amazed to see it crystal clear just like the stuff when new!! Truly surprising. I put it back. That was at 90,000 miles and the same lubricant was in the PG1 when some years later, I drove the car to the local car breakers on the final day of it's MoT.

The engine and gearbox was still faultless with the odometer showing 133,000 miles on its final day. I could have repaired the cosmetically tatty wheel arches and continued using one of the most reliable cars we've ever had. However, it had to make way for the newly arrived MGZS 120. That replacement car is now in its eleventh year since we bought it new in 2003. Almost as reliable as the Montego it replaced and that's saying a lot. No tatty wheel arches on the ZS ...

 

They are supposed to be fill for life. Though, I don't know the reason why, but renewing mine, made the groan when turning tight corners go away completely, it is silent now. After renewing the fluid, I have only been checking the level periodically, still has the same fluid for about 2 years now which has done about 20000 miles still no problems.

 

John, yes it is true what you have observed. All older cars that have done some high mileage, hondas, peugeots, toyotas, vauxhalls, e.t.c that I have driven, have had a slightly harder to engage second gear, when downshifting, compared to the other gears. Also I have noticed that if you allow the speed of the car and engine revs to drop to the normal speed for second gear then it engages easier.

I still use the old school method of downshifting through the gears i.e 5th, then 4th, then 3rd then 2nd as the car slows down even though modern driving schools say not to do this. The modern driving schools encourage people to just shift straight from 5th to 2nd when slowing down and I believe this is not good for the 2nd gear synchro or even the engine as it will spend some time lugging at very low revs when you are on the brakes slowing in 5th gear.

As for gearbox fluid, I wish manual transmission gearbox designers, incorporated a dip stick or some other quicker, easier means of checking the fluid level.

 

...
I still use the old school method of downshifting through the gears i.e 5th, then 4th, then 3rd then 2nd as the car slows down ...

Thi is exactly the same way how I am shifting gears when slowing down. I am afraid I will not change the way how I am doing that no matter what modern driving schools say.

 

Clutch fluid was filthy black. In process of changing and bleeding now. Seems I introduced some air as the clutch pedal is extremely light now with bite point on the about 1cm above the floor.

I usually go down through all the gears 5th 4th 3rd etc. I find I get the best fuel economy that way.

 

It might need bleeding then. I believe the clutch fluid should be changed every two years even though the service manual mentions nothing about it. The manual only mentions that brake fluid should be renewed every two years but clutch fluid being identical to brake fluid then must be two years as well, just my reasoning. Only thing is that bleeding that clutch is quite a task, unless you can use vacuum the way MGJohn does with a syringe.

 

I've bled the best part of 2litres of fluid out and still the pedal feels really weak and a really low biting point.

I'm not getting anymore air out, so I'm gonna let it settle and try again tomorrow.

This was the state of the brake fluid that come out of the system

 

I've bled the best part of 2litres of fluid out and still the pedal feels really weak and a really low biting point.

I'm not getting anymore air out, so I'm gonna let it settle and try again tomorrow.

That black fluid is discoloured from many minute seal wear particles as the black seal in the Slave wears away every time that little seal is subjected to huge hydraulic pressure. Considering how small that slave seal is, about the size of a penny coin, amazing they last as long as they do!

The clutch hydraulic system can be VERY difficult to bleed to exclude air from the SLAVE cylinder. When I first worked on the 620ti's system, I could not bleed it at all in the usual way. That is by up-down pedal and bleed nipple opening-closing sequence in the usual way. Could not select ANY gear that first time. Slept on it and had a eureka moment. After pedal up-down to exclude air from the line to the Slave, I removed the cotter pin from the Slave's Push Rod so that when the bleed nipple on the slave is opened, you can push the push rod into the Slave Cylinder with little effort. Then close the nipple and release the push rod. Repeat that open nipple, push rod fully into the cylinder, close nipple sequence three-four times. That should exclude any air from the slave cylinder and when you start engine and engage a gear, you should feel an immediate improvement in the clutch release operation. That has been my experience every time bleeding the system on our various 620ti.

Process still very fresh in my mind as soon after his return to the UK from a 2,000 mile round trip on the continent with his high mileage 620ti two weeks ago, he lost all hydraulic pressure in his clutch release system in Cheltenham. I got a phone message " Dad I need a tow". Got car home. Martin had taken a new slave cylinder with him on the trip. However, there were traces of fluid in the footwell suggesting the Master was faulty.

Took him to the car breakers and he removed a Clutch Master Cylinder from an N-Reg 600 showing 94,000 miles. Fitted that and the NEW Slave and bled the system. Only when he was under the car pushing the Push Rod into the Slave to exclude any air from it, did he have a good pedal 'feel' and smooth selection of all gears.

By the way, prior to his trip he asked me to shop around to get a new slave. I got one @ less than thirty quid from UNIPART. I had asked at my usual XPart supplier who wanted three times that amount for the same item. Other parts suppiers wanted over £100 !

Correction. For less than thirty quid each, I got two! I also got one for myself whilst available at that price from UNIPART. The replacement seal kits for the slave are quite pricey so a complete slave at that price is a good investment in both time and money all things considered. Stripping and refurbishing a Slave with new seals is very time consuming. Been there, done that several times.

Two weeks on, Martin's 620ti runs fine.

 

Bled the clutch so more. Only got a few tiny bubbles out. Pedal feels much better though.

Quick question. How much should the slave cylinder piston move when the clutch is pressed? Mine moves about the length of the forked bit on the end.

 

That should be sufficient movement in a healthy hydraulic system. Has the gear selection improved ?

 

Haven't had chance to test it yet. As I was finishing mine my neighbour asked for help servicing and changing the brakes on his 75. Those rear calipers are a complete pita to get off.

Gear selection feels better even when cold though so I'm hopeful. Fingers crossed.

 

Think I may have made a bit of a breakthrough. Downshift to 2nd is still playing up when hot.

So I figured seeing as the problem occurs when hot I'd get it up on the ramps while hot and have a nose about.

Seems the Gearbox mount is a getting soft when hot. The engine mounts don't move, can't move them at all by hand. The gearbox can be moved backwards and forwards a couple of inches from underneth the car by hand, so this could possibly be the cause of the occasional judder when moving off, thinking it may also be the problem with 2nd, as when the engine and gearbox is cold the gearbox barely moves by hand.

only issue with this is I can't source a brand new mount as the rubber part is nla from rimmers, tried searching ebay but there's none, dunno where else to look.

 

Do you mean the one which bolts with two 13mm bolts to the end of the gearbox with the upwards facing threaded bolt in the rubber mount for the 18mm Nut ? If so, I or my son may, repeat may have one of those spare. 620ti are rare now in local scrapyards. They may have a Diesel 600 which I believe has the same mount as they use the PG1.

Lots of spares over on Rovertech.net held by enthusiasts. One just maybe able to help.

 

i changed my U joint a while ago, got a kit from ebay - seller is a RT member.
made a huge improvement!, now its getting a little sloppy again - time to do the poly bush kit for the stabilizer bar on the gear linkage as it seems a bit soaked in oil from the 1001 minor oil leaks ive had in the past year.
i fix one, another shows up! life of a rover owner..

John,
did you get my pm regarding the hose?

 

Yes, got it thanks.

I've bought several sets of those Polybush replacements for both ends of the PG1 stabiliser bar. Fitted to MG Montego Turbos, 220 Coupes and Rover 620ti turbos. They look better but, quite frankly, I cannot tell any difference. Maybe more resistant to oil and road filth contamination which is a good thing. The old original rubber bushes looked fine when I removed them.

Fitting a more substantial U-J to the Gear Control Shaft to replace the flimsy original, well it gets flimsy over many 1000s of miles and can fracture from metal fatigue, is a really better modification. I always feel a real benefit with that mod.

 

This is the old fluid that I drained from the 620 Sli, that I used to have. The fluid had been in the gearbox for about 120000 miles. It is almost turning black in colour.

I replaced that with this

And this is the fluid that I drained from my 620Ti's gearbox, about two years ago.

I replaced it with 2.2 litres of this;

In both cases, both cars' gear shifts felt much better and much smoother with the new fresh fluid, more so in the Ti where the grinding noise from the differential, when taking tight corners, disappeared completely giving an absolutely silent box.

Sometimes, fresh new fluid solves certain issues. However, I will not renew the fluid that I have on the Ti now, I will just be checking the level and topping up if needed, unless some issue crops up.

Here is a good video on synchronizers.

 

So, the story continues. I changed the engine mount, the judder has gone, but the downshift to 2nd when hot is still a problem.

So while it was hot I decided to get it up on the ramps and have a poke about seeing as that's when the problem occurs.

First I checked the clutch movement.

Clutch Pedal Up.

And Clutch Pedal Down

I also noted that the slave cylinder appeared to be a little damp around the seal. So I have ordered a seal kit from rimmers, along with a new one of these.

Looks a tad worn think you'll agree.

So then I thought I'd check the gearbox oil again, as last time I checked it while cold and the engine hadn't been run, so the oil was cold and settled, and that time it come out a nice golden colour, this time with the oil hot, as the car had just been on a 30ish mile drive, the story was different, and this is what come out of the gearbox. Can only imagine that as the oil is getting hot and the gearbox is whipping up the oil it's bringing up sludge from the bottom.

So cue a trip to GSF and the gearbox oil has been replaced with fresh MTF-94. Bit confused though, as the gearbox swallowed up approx 2.4 litres before it emerged from the filler hole, and yes the car was level when I filled it up, I used a laser level to check as I jacked up the front due to my driveway having a slope.

Fingers crossed the problem will now be sorted. Can't test it till tomorrow at the earliest, but I'll probably just wait until I get the seal kit and pin.

 

Fingers crossed the problem is sorted. 2.4 litres is not bad, only 200 ml more. Better to have a tiny bit more than less.
The manual says to always drain the gearbox while warm as most of the fluid and any contaminants will come out this way.
That clutch slave pin is worn and must have been reducing the range of release movement.

 

So I got the seal kit fitted today, and bled the clutch, also fitted the new clevis pin.

I took her out for a drive and the problem is still there when hot.

So decided to be a little heavy handed, and managed to get it to downshift into second (which I couldn't do before when it jammed up it wouldn't go in at all no matter the force), I know I really shouldn't have, but here's the thing, it got progressively easier each time, it's still not perfect as there is still some resistance downshifting to 2nd, but fingers crossed it'll continue to get better.

As a side note, the oil change and changing the seals and clevis pin as made the rest of the changes an absolute dream, they are silky smooth, and the car seems quieter too.

 

Mine has gone through 2 clevis pins (its on its 3rd!). It even wore the hole in the clutch arm out of round so much so that it was in danger of breaking. I welded it up and drilled it again and it made the clutch so much nicer.