LT77 gearbox 5th gear crunching

LT77 gearbox 5th gear crunching

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Discussion

JJREED

Original Poster:

56 posts

108 months

Monday 16th May 2016
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So, A problem with 5th gear. Always been there since I've had the car but might be getting worse. 5th gear crunches BADLY. Sometimes cannot engage.

If I'm very quick it goes in with a little crunch. If very , very slow, it mostly goes in.

However changing gear normally is crunched very badly - I'e' like not disengaging the clutch at all.

The odd factor is that it slots in beautifully ant the crunches when I let the clutch out. No crashing at all with the clutch depressed, only when the clutch is lifted, so I'm not sure it's synchro rings.

It seems to shift 'OK' mostly below 40 mph, and above that if I shift into 5th but move the lever to the left so I'm almost selecting 3rd after I go through the gate, then I can get it to shift cleanly every time.

Almost like it's selecting 3rd and 5th at the same time.

Ideas?

rev-erend

21,412 posts

284 months

Monday 16th May 2016
quotequote all
The bushes in the linkage probably need changing.

Also - gearbox oil needs very regular changing.

JJREED

Original Poster:

56 posts

108 months

Monday 16th May 2016
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Done the oil but no better - I had hears about the bushings, is it possible to strip these out and change them without dropping the box out of the car?

blitzracing

6,387 posts

220 months

Tuesday 17th May 2016
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If the TVR is the same as my car, this is worth a read. Get the spring loading wrong on the gear lever that allows it to drop into 5th easily could prevent it meshing into 5th properly. Im my case I cut a hole in the transmission tunnel to allow access to the mechanism and then re glassfibre'd it afterwards, otherwise its an engine and gearbox out job.

http://www.gomog.com/allmorgan/remoteissues.html

carsy

3,018 posts

165 months

Tuesday 17th May 2016
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The remote linkage that TVR used on the Griff and Chim LT77`s differ considerably from those used on the typical SD1`s and Wedges. As such there are no rubber bushes to change. Its a metal casting that just bolts hard up onto the gearbox.

You mention it goes into gear fine if you alter its natural path and go more towards 3rd. This would indicate that the syncro is fine and it may just be an alignment problem.

Have a read here re setting up the lever gate and alignment.

http://www.gomog.com/allmorgan/remoteissues.html


On these boxes there is also a plastic sort of cup which the lever sits in. This can wear and cause problems. You can get a new one from Tvr Power. Fidly to fit but can be done with the box in situ.

http://www.powersperformance.co.uk/store/slug/gear...


Hope this is of some help.

rev-erend

21,412 posts

284 months

Tuesday 17th May 2016
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These guys are very good for advise and rebuilds..

http://www.gearboxman.co.uk/

JJREED

Original Poster:

56 posts

108 months

Wednesday 18th May 2016
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Thanks all - Took some advice from Ashcroft transmissions and will adjust the lever centre point.

rev-erend

21,412 posts

284 months

Tuesday 24th May 2016
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Did it work ?