Gearbox failure

[Bobgriff]

Hi chaps,

Gained approval from 'the boss' indoors' to go for an extended drive this morning which unfortunately on lasted 30 mins. Whilst driving along I sensed that something was not quite right so took it steady. I started getting a grinding/ knocking noise that at first I couldn't pinpoint, after a few miles it was getting worse so I turned for home. During the drive home it became more apparent that the noise is mainly whilst in 5th gear but a fainter noise can be heard in 4th, so it sounds like a gearbox rebuild to me .

Just wondering if anyone has experience a similar scenario and if so what did it turn out to be?

The car was only serviced last month (250 miles) ago and I'm wondering if the wrong fluid being used could have contributed to the failure. Is this plausible? or would the rapid onset of the problem rule this out? just a though!

Anyway, some calls to be made tomorrow to find out when I can get it fixed, no growl for me this year unfortunately, shame as I was really looking forward to it. I'm sure you'll all have a great time

Any thoughts or advice welcomed.

BobGriff

[griffdude]

Is the noise definitely from the gearbox area? I've just had a CV joint fail & the noise seemed to be more prevalent in higher gears/speeds.

[A900ss]

Bad news Rob. Sounds like both Paul and you have problems.

Hope they are both sorted quickly and cheaply.

Karl.

[Bobgriff]

Griffdude, thanks for the info, I will be glad to be proven wrong but I do think its gearbox as I tried different gears at different speeds and it always seemed to be 5th and moderately in 4th. I'm not sure if these two gears are interconnected in any way, certainly hope your right as I'd prefer to spend the money on other (shiney) stuff. Will get it into a garage for diagnosis as soon as I can.

Karl, hope you had a great day today thundering through those tunnels. Hopefully we can all get the cars running for a north wales blast at some stage.

[5.0ltr]

T5 or LT box?

[5.0ltr]

T5 or LT box?

[Bobgriff]

Sorry chaps, for clarity it's a T5

[5.0ltr]

T5 is a strong box, but some parts for the LT are getting rare so slightly good news if it is gearbox. My garage does gearbox fluids change on 12k only for info.

[Pete Mac]

Bobgriff said:

Sorry chaps, for clarity it's a T5

Rob

Not sure if you are a DIY man or not but there is quite a lot of stuff on here for your info:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

There seems to be a lot more stuff and expertise in the US than in the UK on the T5. This is only a guess but it sounds more like a bearing than an actual gear and it might be an idea to drop the oil to see what comes out with the oil...! As someone else says, the T5 does have a reputation for being a tough old box.

I guess, unless it is something obvious, it means a 'gearbox out' job and once you've got the box stripped down, you may as well replace all the bearings anyway. Plenty of good kits from 'fleaBay'.

Sorry I can't be of more help, Pete

[pjac67]

Sorry to hear this Rob - hope its not off the road too long...definitely up for a Welsh trip (when I have a car...).

Regards, Paul.

[Number 7]

I believe 5th gear in the T5 is a weak point - I've heard of a few failures. A company that has rebuilt my LT77 told me years ago that in the Griffs / Chims its because of the lack of support around the gearbox.

[Bobgriff]

The car is being picked up on Friday by a local garage that has recently done another 'grief' Gearbox. They recommended not to drive it as it could do more damage, hopefully it's just a bearing and no further damage.
I will let you know the outcome, fingers crossed all the gears are in good nick.

[Bobgriff]

The car is being picked up on Friday by a local garage that has recently done another 'grief' Gearbox. They recommended not to drive it as it could do more damage, hopefully it's just a bearing and no further damage.
I will let you know the outcome, fingers crossed all the gears are in good nick.

[A900ss]

Hope all goes well Rob. I'm up for a trip to the Triangle in July if you and Paul have working cars.

I've also managed to get another days holiday (long story) so potentially could go on a weekday as well if others prefer.

[Englishman]

Yes, 5th gear on a T5 box has caused me problems twice in different TVR's. First time just lost 5th, the other time gearbox locked solid, hence rear wheels locked solid on a motorway and put me into a spin (not a pleasant experience!). Both down to 5th gear coming adrift due to a circlip failing I was told.

[phazed]

Englishman said:

Yes, 5th gear on a T5 box has caused me problems twice in different TVR's. First time just lost 5th, the other time gearbox locked solid, hence rear wheels locked solid on a motorway and put me into a spin (not a pleasant experience!). Both down to 5th gear coming adrift due to a circlip failing I was told.

Me to, just lost 5th while cruising at about 60, no load at all.

I was on my way to Shakespeare raceway for a drag day and still completed 17 runs.

I didn't know then that damage could be done by a floating gear

[Pete Mac]

Bobgriff said:

Hi chaps,

The car was only serviced last month (250 miles) ago and I'm wondering if the wrong fluid being used could have contributed to the failure. Is this plausible? BobGriff

Rob, it might be complete coincidence but my understanding is that if you use ordinary gearbox oil in the T5 instead of the recommended automatic transmission fluid (ATF), it is too viscous to reach all lubrication points and particularly one of the bearings and they tend to disintergrate - there is a lot on the web about this. Could be complete coincidence that you have just had the car serviced but.......

I might be taking you down a 'rabbit hole' and you are just unlucky but well worth checking. This is one of the reasons why I like to do my own servicing on my Griff, at least I know what I am putting in the car. Pete

[Bobgriff]

Pete Mac said:

Rob, it might be complete coincidence but my understanding is that if you use ordinary gearbox oil in the T5 instead of the recommended automatic transmission fluid (ATF), it is too viscous to reach all lubrication points and particularly one of the bearings and they tend to disintergrate - there is a lot on the web about this. Could be complete coincidence that you have just had the car serviced but.......

I might be taking you down a 'rabbit hole' and you are just unlucky but well worth checking. This is one of the reasons why I like to do my own servicing on my Griff, at least I know what I am putting in the car. Pete

It has crossed my mind and is deffinately an area for investigation. The car is service by a reputable TVR competent garage but you just never know so will be getting it checked out just in case.

I will let you all know the progress.

Thanks guys.

[Pete Mac]

Pete Mac said:

Rob, it might be complete coincidence but my understanding is that if you use ordinary gearbox oil in the T5 instead of the recommended automatic transmission fluid (ATF), it is too viscous to reach all lubrication points and particularly one of the bearings and they tend to disintergrate

In fact it was in my previous thread. Memory is short, it must be the alcohol or old age or both.....Pete

ATF for a T5 is really just for the World Class T5 that has a unique sychronizer that gear lube cannot squeeze in to lubricate. The syncros like light oil where the gears like heavy oil. The bearings are fickle too, they don't get any oil if the oil is too heavy.
• The WC T5 has papercone synchros and roller bearings on the speed gears. These tiny rollers need the thin oil for lubrication. They were designed for ATF and work well with it.
• W/C T5's have needle bearings under gears #1, 2, &3.
• The lubricant required for W/C/ T5's is automatic transmission fluid (ATF).dexron111
• W/C t5’s must use ATF dexron111 and penrite Lubrizol
• you absolutely HAVE to run the right fluid in the WC units. If you use gear oil in one of those, it'll ruin the clutch material in the synchronizers. The synchro clutch material is the same as the clutches in an automatic trans, hence the reason you have to use ATF in them

[Bobgriff]

So, looks like I've been proved wrong! The gearbox and diff oil was drained, gearbox oil was fine but the diff oil contained lots of slivers of metal, on further inspection I am told at least one of the gear teeth is missing and there are other score marks in there.
Now to decision time.... Do I get it reconditioned (gkn diff) which I recon will cost a bomb as it will require new gears and parts for these are like hens teeth, buy a second hand one with the risk it will not last, or buy a BTR diff and new mounts from central. I'm thinking that the new one is probably the best option but they're a grand and have been sitting around in a humid environment in Malaysia for the last 10 years.

I'm also still a bit worried about the gearbox as my diagnosis was based on the fact that I only had rumbling/ grinding noises whilst in gears 4 and 5. Worst case scenario is both need replacement, really hope it's just the diff or the kids could end up getting thinner. Any thoughts chaps?