Vibration in 5th Gear Only
Discussion
wilksy61 said:
told me that all T350's vibrate through the chassis in 5th gear.
Ahh...the good old "they all do that sir". Back in the day it was the TVR factory's favourite explanation for everything 
I've never heard of it before. Have you tried phoning another specialist (e.g. James Agger) for an opinion?
The gearbox in these cars is a Borg Warner/ Tremec T5. Quick search on T5 vibration in 5th comes up with:
https://www.jalopyjournal.com/forum/threads/chasin...
Seems to be a known problem and requires a gearbox rebuild.
https://www.jalopyjournal.com/forum/threads/chasin...
Seems to be a known problem and requires a gearbox rebuild.
It's wrong. It isn't right. Back it.
TBH the gearbox is unlikely to be the cause, it may be that the overdrive 5th is allowing drive shaft whip to show up in the extra gear lash when in 5th, which you can then hear/feel when on light load at speed. The whip can come from the misalignment of diff Vs gearbox, the two need to have their shafts aligned to parallel lines (although trial and error adjustment is often still needed). You may get a clue if it can be encouraged in 3rd on mild acceleration and high speed overrun.
All a bit techy but if the diff mounts are shagged it will rotate slightly as torque is applied, altering the angle relative the gearbox/engine centre line. Could be the gearbox is low at the tail, or even the engine mounts hanging so tail high but suspect tail of box/diff. So it needs a proper look over before the T5 is condemned. Doesn't take much misalignment, I had similar and added C washers to the gearbox mounts, crunched the box up hard and squeezed them in, the 1/4 inch lift cleared the vibration.
Doubt a regular hourly paid "part numbers mechanic" will sort this, sadly.
TBH the gearbox is unlikely to be the cause, it may be that the overdrive 5th is allowing drive shaft whip to show up in the extra gear lash when in 5th, which you can then hear/feel when on light load at speed. The whip can come from the misalignment of diff Vs gearbox, the two need to have their shafts aligned to parallel lines (although trial and error adjustment is often still needed). You may get a clue if it can be encouraged in 3rd on mild acceleration and high speed overrun.
All a bit techy but if the diff mounts are shagged it will rotate slightly as torque is applied, altering the angle relative the gearbox/engine centre line. Could be the gearbox is low at the tail, or even the engine mounts hanging so tail high but suspect tail of box/diff. So it needs a proper look over before the T5 is condemned. Doesn't take much misalignment, I had similar and added C washers to the gearbox mounts, crunched the box up hard and squeezed them in, the 1/4 inch lift cleared the vibration.
Doubt a regular hourly paid "part numbers mechanic" will sort this, sadly.
The 5th gear is a known weak point in the T5 gearbox, as suggested by @Adrian speak to John at Readman racing
taken from another site:
"One thing that can cause a rattle in fifth gear is loose counter shaft bearings.
Fifth is the only gear that applies lateral pressure to the counter shaft beyond the rear bearing. all of the other gears apply the pressure between the front and rear bearings, so in fifth, the geometry is different."
taken from another site:
"One thing that can cause a rattle in fifth gear is loose counter shaft bearings.
Fifth is the only gear that applies lateral pressure to the counter shaft beyond the rear bearing. all of the other gears apply the pressure between the front and rear bearings, so in fifth, the geometry is different."
Thanks for all your replies, I to am of the opinion that if a vibration is only in 5th then there's a fair chance its 5th gear as I also searched for T5 5th gear vibration.
The company the car was bought from, and is currently at, is a specialist but it seems they cannot detect this 5th gear vibration and have told me there is no vibration, equally strange bearing in mind the comment "that they all do this", which has now been retracted by the salesman.
The quandary I'm in is what to do next, the previous garage that worked on the car (for the previous owner) and myself have felt this vibration, the company selling it cannot.
It around a 200 mile round trip for me from deepest Essex to the home counties something that I don't want to do too many times and certainly something I didn't think I would be doing after just 100 miles.
The car was bought on finance and the finance company have been kept in the loop by myself.
The company the car was bought from, and is currently at, is a specialist but it seems they cannot detect this 5th gear vibration and have told me there is no vibration, equally strange bearing in mind the comment "that they all do this", which has now been retracted by the salesman.
The quandary I'm in is what to do next, the previous garage that worked on the car (for the previous owner) and myself have felt this vibration, the company selling it cannot.
It around a 200 mile round trip for me from deepest Essex to the home counties something that I don't want to do too many times and certainly something I didn't think I would be doing after just 100 miles.
The car was bought on finance and the finance company have been kept in the loop by myself.
PuffsBack said:
Given you are in Suffolk I would take it to either Scole Engineering (Diss) or Mat Smith (Downham Market) Either is highly respected TVR specialist and get their opinion.
Good advice, my old Tamora was vibrating more than usual when 5th gear was on its last legs at 24k miles, worse still it would graunch when changing from 4th to 5th gear at anything over 3k revs, the gearbox was sent away to be reconditioned and would have cost in the region of £800 at the time, luckily the warranty covered the parts and labour costs and the box was good as gold afterwards 
Gassing Station | Tamora, T350 & Sagaris | Top of Page | What's New | My Stuff