Grinding selecting third

Hello all,

I've been going through the forum in relation to the grinding when I select third.

I've had the gearbox out to replace the release bearing and did the clutch while I was in there.

Since the surgery I've had a grinding noise when selecting third quickly (gently selecting third is fine).

I've switched it to mondo mode as my vcu was on the way out (OWUT result of 90 to 105 seconds) - could this be the cause?

I know the Haynes manual says MTF94 but when I went to halfords there was none stocked and was told Comma manual gear oil MVMTF Plus 75W90 was a substitute - is this true?

Any help would be greatly appreciated.

Caseymi said:

I've had the gearbox out to replace the release bearing and did the clutch while I was in there.

Click to expand...

What engine?

Caseymi said:

I've switched it to mondo mode as my vcu was on the way out (OWUT result of 90 to 105 seconds)

Click to expand...

good plan.

Caseymi said:

could this be the cause?

Click to expand...

No

Caseymi said:

I know the Haynes manual says MTF94

Click to expand...

That's correct.

Caseymi said:

and was told Comma manual gear oil MVMTF Plus 75W90 was a substitute - is this true?

Click to expand...

No. It's completely incorrect and not compatible.
A 10W40 engine oil is a close and suitable emergency oil to use.

An oil that's too heavy will reduce the effectiveness of a weak synchromesh cone, which is what it sounds your gearbox has.

Try replacing the current oil with Dexron 2 or 3 automatic transmission fluid for a while. This has similar properties to MTF94, but also contains a powerful detergent, which will clean the synchromesh rings.

Caseymi said:

Hello all,

I've been going through the forum in relation to the grinding when I select third.

I've had the gearbox out to replace the release bearing and did the clutch while I was in there.

Since the surgery I've had a grinding noise when selecting third quickly (gently selecting third is fine).

I've switched it to mondo mode as my vcu was on the way out (OWUT result of 90 to 105 seconds) - could this be the cause?

I know the Haynes manual says MTF94 but when I went to halfords there was none stocked and was told Comma manual gear oil MVMTF Plus 75W90 was a substitute - is this true?

Any help would be greatly appreciated.

Click to expand...

I would be surprised if Halfords don't have any MTF94 oil.

Even over here I can go to the car parts store and get MTF94 oil. I put Penrite oil in my gearbox 5 years ago and its been fine. Think it was this...

https://www.penriteoil.com.au/products/trans-gear-75w-80-semi-syn#/

I believe MTF94 is not disimilar to a fully synthetic API GL-4, but I wouldn't say they are the same as there may be differences - eg MTF94 may have protective properties for the plastic parts used in the PG1 gearbox. You have to get the correct viscosity as well.

The 75W90 spec is right for the IRD I believe.

Nodge68 said:

What engine? good plan.
No

That's correct.

No. It's completely incorrect and not compatible.
A 10W40 engine oil is a close and suitable emergency oil to use.

An oil that's too heavy will reduce the effectiveness of a weak synchromesh cone, which is what it sounds your gearbox has.

Try replacing the current oil with Dexron 2 or 3 automatic transmission fluid for a while. This has similar properties to MTF94, but also contains a powerful detergent, which will clean the synchromesh rings.

Click to expand...

Hi Nodge,

Thanks for coming back to me.

Its a 2005 TD4 engine.

What I think I will do is drain the box and replace the oil with 10W40 engine oil to tide me over till the weekend and get some MTF94 on Saturaday.

Thanks.

GrumpyGel said:

I would be surprised if Halfords don't have any MTF94 oil.

Even over here I can go to the car parts store and get MTF94 oil. I put Penrite oil in my gearbox 5 years ago and its been fine. Think it was this...

https://www.penriteoil.com.au/products/trans-gear-75w-80-semi-syn#/

I believe MTF94 is not disimilar to a fully synthetic API GL-4, but I wouldn't say they are the same as there may be differences - eg MTF94 may have protective properties for the plastic parts used in the PG1 gearbox. You have to get the correct viscosity as well.

The 75W90 spec is right for the IRD I believe.

Click to expand...

The Halfords where I live doesn't have the greatest selection of anything, I went in looking for MTF 94 and was told the MVMTF Plus 75W90 was perfectly acceptable for the job.

Lesson Learned: don't listen to the halfords sales assistant when it comes to substitute oils.

Caseymi said:

Its a 2005 TD4 engine.

What I think I will do is drain the box and replace the oil with 10W40

Click to expand...

A TD4 box can use 80w90 or MTF94. However it sounds like the synchromesh rings are worn or dirty. So I'd definitely run it with Dexron 2 or 3 for a few hundred miles, to clean the box of contaminants.

Then replace with MTF94, once the shift quality has returned.

Nodge68 said:

A TD4 box can use 80w90 or MTF94. However it sounds like the synchromesh rings are worn or dirty. So I'd definitely run it with Dexron 2 or 3 for a few hundred miles, to clean the box of contaminants.

Then replace with MTF94, once the shift quality has returned.

Click to expand...

Thats exactly the info ive been looking for

I had the same problem in my TD4 and someone here suggested doing an oil change and filling it with ATF. After a hundred miles or so the issue disappeared and for the next thousand or so miles that I owned the car it was fine. I Did another oil change after around 200 miles and refilled it with ATF again as it seemed to be fine with it.
I'm not saying it will work for you but it did for me.