Clio 200 third gear crunch ( ktec rebuilt 7 months ago)

[Hsustyler]

Gearbox had work done by K-Tec Racing July 2025. Invoice shows:

• 3rd gear synchro ring replaced
• 4th gear synchro ring replaced
• 3rd and 4th synchro hub replaced due to crunching
• New genuine Renault slave cylinder
• Filled with Millers 75W90 FS

Car has covered under 7kcmiles since.

Now it’s doing this:
Consistent slight crunch going 2nd to 3rd.
Consistent slight crunch going 4th to 3rd.
Everything else is clean.
Engine off it goes into gear perfectly.
If I rev match, it reduces the crunch.
It's only ever 3rd gear engagement.

- Before I start pointing fingers, I’m going to drop the 75W90 out and put the correct 75W80 GL4 in.

Those who know these boxes:
Does this just sound like 3rd synchro again?

Has anyone seen 75W90 cause this specifically on 3rd?

Anything else worth ruling out before assuming internal?

Would you bother checking cables or clutch hydraulics given it is gear specific?

Looking for experience based input.

 

[Clio_fool]

@NorthloopCup will probably confirm your suspicions. No wonder K tec shut their workshop 🙄.

 

[NorthloopCup]

It’s worth bleeding the clutch to rule that side of things out first, but it’s a good chance the synchro is goosed again.

 

[RSRowe]

Has anyone seen 75W90 cause this specifically on 3rd?

Yep. Had this happen and seen it happen.

It’s worth bleeding the slave, but the damage has been done now. In my opinion, if it was an issue with the operation of the clutch, chances are it would affect every gearshifts (not just the ones into 3rd).

Fuchs sintofluid made a significant difference to the crunchiness of my original gearbox. I got an additional 12 months out of it on track before it got really bad again.

 

[Hsustyler]

It’s worth bleeding the clutch to rule that side of things out first, but it’s a good chance the synchro is goosed again.

Appreciate the feeback, will try that first and see how it goes.

 

[Matt Cup]

Surely if it’s less than 12 months they are obligated to fix it?

Don’t parts have a 12 months warranty?

 

[Hsustyler]

Surely if it’s less than 12 months they are obligated to fix it?

Don’t parts have a 12 months warranty?

You'd think so right? But they don't offer a warranty on TL4 Gearbox synchro rebuilds.

Their exact words-
"Unfortunately the time has expired on gearbox warranty.


Our workshop has now been closed so we are now unable to inspect or repair vehicles.


Millers 75W90 is the gearbox oil we used in all our gearbox builds for the last 10 years."

Now they are blanking us after we mentioned their statutory obligation under Section 49 of the Consumer Rights Act 2015 for repair work to be done with reasonable care and skill and to be durable for a reasonable time, regardless of any voluntary warranty.

durable for a reasonable time.. Now it's crunching after less than 6k miles. Ktec aren't even interested in taking a look.

 

[Ant1]

That sucks

Never been a fan of Ktec.

 

[Matt Cup]

If you paid by CC then maybe section 75 will be able to help recover some funds?

 

[Hsustyler]

That sucks

Never been a fan of Ktec.

Same. Only ever dealt with their online shop and they had a habit of delaying or messing up orders. Real shitty attitude towards customs..bill here for over 3k less than 8 months ago and they have no interest in hearing about it.

 

[Hsustyler]

If you paid by CC then maybe section 75 will be able to help recover some funds?

Good idea but was with debit card.

 

[NorthloopCup]

Put some of this in the box.

Cera Tec

High-tech ceramic wear protection. Reduces friction and wear through ceramic compounds offering high chemical and thermal resistance. Prevents direct metal-to-metal contact, thus increasing the assembly service life. Reduces fuel consumption in gasoline and diesel engines thanks to the...

www.liqui-moly.com

 

[Hsustyler]

Put some of this in the box.

Cera Tec

High-tech ceramic wear protection. Reduces friction and wear through ceramic compounds offering high chemical and thermal resistance. Prevents direct metal-to-metal contact, thus increasing the assembly service life. Reduces fuel consumption in gasoline and diesel engines thanks to the...

www.liqui-moly.com

Nice.Just ordered some

Elf NFX 75w80..add a whole bottle of Cera Tec?​

 

[NorthloopCup]

Nice.Just ordered some

Elf NFX 75w80..add a whole bottle of Cera Tec?​

Whatever it says on the instructions for it mate. I’ve never used it, but I’ve heard of others that have and it’s worked.

 

[koksracing]

so I can’t comment on ktec specifically but a crunch in a newly rebuilt gearbox isn’t that uncommon. It’s bloody frustrating though..I had my box rebuilt (not northloop just to be clear) twice in a season last year and threw pms shifter, clutch, oil, slave at it each time. Crunched straight out at cadwell - 1st gear change…..also ran millers, other oil.

It could be the clutch or slave cylinder - both I have had issues with before even despite being new. One turned out to the clutch needed re-bleeding and the other the slave leaked brand new…

@NorthloopCup has just rebuilt both of my tl4 031 boxes (someone else did them before)and they have the black line diff in. The ceratec stuff I have had recommended by people so I am going to try this in my racecar alongside the standard elf oil and will report back.. thanks

 

[koksracing]

Btw I think the oil does impact it. As I ran oil like you had above and it crunched worse than when I use gl4 specific oil 75w80 oil. However it still crunched so didn’t fix the problem all together.