3rd gear crunch, only when cold.

3rd gear crunch, only when cold.

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Benbay001

Original Poster:

5,794 posts

156 months

Saturday 12th April 2014
quotequote all
The 3rd gear on my 97 MR2 grinds/ crunches when i try to change up or down into third but only when the box and engine are cold.
When i bought the car the box was find, no issues at all.
Shortly after buying it i replaced the clutch and gearbox oil at the same time.
Since then ive had the crunch.

Initially i used some cheap gear oil. I then tried some expensive fully sinth castrol and then, due to a drive shaft popping out when doing the cambelt, i had to replace it again (used more expensive castrol)

Short of an expensive gearbox rebuild, is there anything i can try to try and fix the issue?

Thank you.


GavinPearson

5,715 posts

250 months

Saturday 12th April 2014
quotequote all
Bleed the clutch. Check you are getting full pedal travel - i.e. full disengagement.

Benbay001

Original Poster:

5,794 posts

156 months

Saturday 12th April 2014
quotequote all
GavinPearson said:
Bleed the clutch. Check you are getting full pedal travel - i.e. full disengagement.
My dad says, if that was a problem it would happen on all gears.
Is he wrong?

S0 What

3,358 posts

171 months

Saturday 12th April 2014
quotequote all
It would be more noticable in reverse is it was clutch drag, normaly cold shift crunching happens in 2nd as it's the more stressed gear (usually) so wears first, did you use the correct grade oil ? expensive meens nowt if it's the wronge grade oil?

GavinPearson

5,715 posts

250 months

Sunday 13th April 2014
quotequote all
Benbay001 said:
GavinPearson said:
Bleed the clutch. Check you are getting full pedal travel - i.e. full disengagement.
My dad says, if that was a problem it would happen on all gears.
Is he wrong?
Yes. If you have enough synchro capacity in the other gears they will not crunch on incomplete disengagement.

As somebody who has worked in the OEM Manual Transmission arena, and trained the 'experts' that the dealers go to when they can't figure stuff out my recommendation is always to check the oil level, bleed the clutch and check that the gear cables on FWD vehicles are correctly adjusted before undertaking any work on a transmission that works in a subpar way.

Benbay001

Original Poster:

5,794 posts

156 months

Sunday 13th April 2014
quotequote all
Deffinately the correct grade oil.
Ill try bleeding the clutch. (probably next weekend now) and get back to you.
Would a clutch with air feel any different?

buggalugs

9,243 posts

236 months

Sunday 13th April 2014
quotequote all
Nah, the bite might be right at the bottom, or past it! Mine always crunched into 2nd, fancy oil made it a lot better. I just lived with it and it didn't seem to get any worse in the 5 years I had it.

Benbay001

Original Poster:

5,794 posts

156 months

Sunday 13th April 2014
quotequote all
My biggest worry is selling it.
Which will be at the end of this year.
Im happy to live with the crunch.
But i worry that if someone test drives it the crunch will be enough to put them off buying. Would like to get it sorted.
Whats the likely cost of a rebuild?

Heaveho

5,279 posts

173 months

Tuesday 15th April 2014
quotequote all
I've had the same issue with my Evo into 2nd when cold for ages. I tried Millers nanotech in the correct grade, which only made things worse. It now runs Redline GL4 75/90, which has greatly improved the shift generally. Worth a try for £50!

Benbay001

Original Poster:

5,794 posts

156 months

Tuesday 15th April 2014
quotequote all
Heaveho said:
I've had the same issue with my Evo into 2nd when cold for ages. I tried Millers nanotech in the correct grade, which only made things worse. It now runs Redline GL4 75/90, which has greatly improved the shift generally. Worth a try for £50!
Ive heard that from others too!
Will get some