Cold Gear Selection
Cold Gear Selection
Author
Discussion

ian-raw

Original Poster:

32 posts

260 months

Tuesday 8th January 2008
quotequote all
Hi all, I have a little problem I am hoping someone out there may be able to point me in the right direction.

If I leave the car in the garage for a week or more its near impossible to select a gear, with a little giggling of the gear leaver and the clutch pedal I can find a low gear, once the car is moving gear selection is notchey, and once done 10 or so miles everything goes back to normal until the car is left sleeping for any length of time? The pedal position a feel seems normal and it only a problem until the car warms up, no noise that points to the box or thrust bearing?
Searched the forums but nothing points direct to any direct solution?

Can any one help?

Many thanks

Ian

Steve_T

6,356 posts

302 months

Tuesday 8th January 2008
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Ian,

I'd check the level of the clutch fluid in the reservoir and look for a small puddle of fluid under the car. I left mine for a few weeks and found the pedal was only working for a small portion of the range. Rolled the car back to check for a leak from the slave and sure enough there it was. Checked the reservoir and it was empty. Topped it up and slowly pumped the pedal in and out and I could see the bubbles as they made their way to the top of the system. Hey presto normal operation resumed.

Steve.

fatjon

2,299 posts

243 months

Tuesday 8th January 2008
quotequote all
Could also be a the wrong grade of oil in the box. Sometimes they get filled up with thicker oil and it makes the synchro sluggish until the oil warms up and thins out. If the clutch fix doesn't work it may be worth a box oil change.

Jon

shpub

8,507 posts

302 months

Tuesday 8th January 2008
quotequote all
fatjon said:
Could also be a the wrong grade of oil in the box. Sometimes they get filled up with thicker oil and it makes the synchro sluggish until the oil warms up and thins out. If the clutch fix doesn't work it may be worth a box oil change.

Jon
Ohhhh be careful... the Oil Police will be after you. wink

ATF which is what TVR recommended does go a long way to solving this problem. However there is a considerable momentum building up that the use of ATF is a bodge, the gearbox will melt and the sky will fall down and civilization as we know it will no longer exist. My Cerbie gearbox has done 100+k miles on ATF and is still fine. It is now running in my Griff as the Griff one needed some TLC so I swapped them over while I got the Griff one rebuilt. The rebuilt Griff one is in the Cerb and I am running 75W90 in it. And yes it is notchy especially 5th and reverse. Once warm it is really nice.

But yes as you say, changing back to ATF may well be the answer.

I also had some high spots on the flywheel which caused selection problems. Ended up skimming the flywheel on a lathe. That solved that problem.

Buffoon

881 posts

234 months

Tuesday 8th January 2008
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Using my third box at the moment, and this one is the quietest by far, but changing 1st to second, and second to third cold is a real pain. Have to pause in neutral for a second or two. Failure to do this ends in a crunch, and that makes me want to cry profusely, so very carefull not to do this. Jumps out of reverse if you don't hold on to it too.

Running on ATF as far as I know.

2nd gear clears first when warm, and third when fully up to temperature. Am hoping will improve with age. Does not matter if left for a week or a few hours.

ridds

8,372 posts

274 months

Tuesday 8th January 2008
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After seeing the internals of my box after 3rd gear tore itself to pieces and the amount of play in the Input and Output shafts seen on 3 seperate boxes I'd say the T5 is a pretty shite box in all honesty.

Buffoon

881 posts

234 months

Tuesday 8th January 2008
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ridds said:
After seeing the internals of my box after 3rd gear tore itself to pieces and the amount of play in the Input and Output shafts seen on 3 seperate boxes I'd say the T5 is a pretty shite box in all honesty.
Your reassuring words have gone no end to giving me peace of mindhehe

350Matt

3,908 posts

309 months

Wednesday 9th January 2008
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The main problem with the T5 ( if you can call it that) is that Borg warner / Tremec only rate it to 300 ft/lb and TVR fitted to cars which generate considerably more than this...


Hardly the boxes fault.

It is a very old gearbox as it originally had 3 speeds way back when so its been upgraded and upgraded over the years which also explains why its so small, put it next to a tremec TKO600 and you'll see what I mean.

and yes do an oil change and put the semi synthetic 75W-90 in

With a decent lube and if built correctly these boxes are pretty reliable up to 350ft/lb, over that they need better bearings at least and better gear material.

Matt

ridds

8,372 posts

274 months

Wednesday 9th January 2008
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The really worrying thing is if you belive the Tremec site the TVR box, Tag number 1352-000-248, which I'm pretty sure mine is.

Is only rated to 231 lb/ft! Although this is on a 5500lb car (2.5 Ton so there's a little to play with I guess).

It's only teh 249 and 251 boxes that are rated to 300 lb/ft