Gear oil and 2nd/3rd gear crunch questions....

[DominicJeans]

Hi all!

I have got the old 2nd/3rd gear crunch issue in my phase 2 172. I have had it for ages and it's no worse BUT it does get better when the box and engine are very warm, i.e. after a motorway blast.
Now, I have it booked in for a gear oil change in the hope that it will help. Is there any chance that this may make it worse or indeed, make it so that the crunch isn't mostly eradicated when the box and engine are at high temperarures?
Any comments or thoughts would be very appreciated.

Ta


Dom

 

[Gandi69]

What oil is in it? I run 75w90 in mine

 

[DominicJeans]

no idea! i guess what it came from the factory with.

 

[warwickstingray]

Let me know if this makes a big difference. Put some 'better' oil I had lying around when I had to remove my driveshaft on my 106 and it's doing the same thing. Almost like the oil is preventing the synchro doing it's job. If I slow my gear changes to a snails pace I can usually get it in gear without a crunch.

 

[DominicJeans]

will do... it's getting it done right now. Andy at Quartz is flushing it out with one load before putting another batch in. Fingers crossed.

 

[Silent_Scone]

Changing the oil will help depending on how warn the syncro and teeth are. If you've been grinding around in it for yonks it probably won't make it much better as the syncro rings will be knackered

 

[DominicJeans]

I am prepared for there being not a lot of cahnge but I thought it's worth a try. the thing I find weird is that when it's super hot then it will not grind until above 5-6k revs. when it's cold, it does it at 2k-3k. Currently, changing down from 3rd to 2nd at speed is a big no-no as I'm sure that would make things let go.

 

[Budgie]

When it inevitably breaks, drop me a PM and i'll swap the boxes over for you.

I'm on in Chertsey and do them CHEAP.

 

[DominicJeans]

gonna have 75/90 in it. ...

Hope it doesn't break. Been like it for 30 odd thousand miles so crossed fingers. When you say cheap, how much are we talking?

 

[DominicJeans]

as I was afraid may happen, it's made it worse. i.e. it doesn't now get better when warmed up like it did before.. Is that because I used 75w/90 instead of 75w/80? There can't be THAT much difference, surely?

 

[Iceberg_172]

I had the same problem. Used 3 litres of castrol syntrans 75w90 from halfords and it cured it

Supposedly, it needs to be GL4 spec and you have GL5? Or maybe the other way around

 

[DominicJeans]

It was a lot better when cold this morning then got worse as it warmed up ---which is the exact opposite of what used to happen!!!. I have decided that gear oil is a funny old game...

 

[warwickstingray]

I put some cheapo comma 75w80 in my 106 this weekend was almost instantly better than what was in previously. Seems that how slippery the oil is varies a lot even within the thickness gradings. Said for some Peugeot/citroen gearboxes on bottle and was closest I could get to recommended total brand oil. My box has done 135k and shifted fine even in the cold this morning. Was so crunchy in the warmer mornings last week.