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Cold Gearbox


darren f

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Surprising.. the average G'box only gets a few degrees over ambient Temp.. unlikely it will EVER feel warm to your touch (unless it's ready to sieze:-) Warming up is no longer a genuine concern (this IS the 21st century, not the 19th after all)

Respectfully suggest you dump whatever sludge oil is in the poor thing and refill with HONDA MTF.. this has proven to be superior to Redline and Motul as a Gear lube.. besides Honda prices on the stuff is MUCH less . IF this does not "fix" the problem.. then it's time for a 'refund' for the faulty design box ;-)

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Although not a Caterham, I have a 1988 BMW that had a difficult gearbox when cold, I recently switched to redline MTL, what a difference it made. The Gearbox shifts very nicely now even when cold. I started out with redline in my 5 speed that is in my Caterham.
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Thanks for the replies, the consensus would seem to be that it is a common problem- one of the quirks that give Caterhams their character I suppose *cool*.

 

It is a bit embarrassing when having started up and alerted everyone in the vicinity of your presence, you pull away with a less than impressive 'baaaaarp, clunk, kerrrunch' (if you know what I mean *confused*).

 

I think I may try some of the Redline MTL recommended (...after the warranty period of course *eek*).

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How much oil does the gearbox take ? I plan a change before this Saturday's Llandow.

Also, is Redline MTL off the shelf at Cafco or Halfrauds ?

Andy Mac C7 GON

😬 Team Langoustine. Hard Core Prawn here 😬

 

Edited by - ALLEGRO on 25 Mar 2003 12:25:42

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"Surprising.. the average G'box only gets a few degrees over ambient Temp.. unlikely it will EVER feel warm to your touch (unless it's ready to sieze:-) "

 

What a load of cobblers - My boxes on my sevens & MG regularly feel warm - on a long trip like down to Le Mans the heat conducts up the gear lever eventually. Whether this is heat generated in the box or conducted from the engine is another matter. Wherever it comes from it thins the oil.

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Gearboxes that don't select gear well until they warm up have been around for a long time.

 

This was always considered to be a classic Ferrari trait and I had a 1600HF Fulvia that was exactly the same.

 

It was always easier to change from 1st to 3rd when it was cold.

 

As most gearboxes lose about 1.5 - 2% transmitted power per mesh engaged it would be a miracle if they didn't warm much above ambient and you couldn't run the car on a really cold winter day as the box would never reach operating temperature. (Minimum probably about 40 degC to give the right clearances) If the oil is too cold you would certainly get quite poor scuffing performance and quite bad wear.

 

I would guess most Caterham boxes run at around 50 degC and maybe even hotter given a real good thrashing. In the limit with really powerful engines in race cars transmission coolers may not be a bad idea.

 

Has anyone put a temperature measuring strip on their car and taken readings?

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I've also had exactly the same problem with mine. I adopted the change from 1st to 3rd method until warmed through. However I think I will try Redline MTL after reading this thread as it clearly seems to make an improvment. Looks like DT will be doing some good trade over the next few days!

 

Phil, frustrated ☹️ it's on axle stands at the moment!

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