Faulty diesel auto after MOT

F.G

My turbo diesel automatic went for MOT last Monday, unfortunately it failed the smoke test.
The garage put an additive in the fuel and told me to use the car all week (car not usually used much in the summer).
Car went for retest on Friday and passed but it now has delayed gear changes and is particularly rough from 1st to 2nd (4 speed box) with a noticeably jerk into 2nd.
All oil levels were checked before MOT, gearbox oil is still pink and in the same place on the stick.
As you can probably imagine I am not happy:mad:, the gearbox on this car is usually very smooth with barely noticeably gear changes.
I cannot get hold of the garage (don't work weekends).
Wondered what you guys think of this and how I should approach the garage Monday morning.

Hammyman

Sticking in the fuel additive has absolutely nothing to do with the gearbox going faulty nor anything to do with anything that happens during the MOT. Its merely co-incidental..

When you checked the gearbox oil level, was it with the engine running? Most auto boxes require you to have the engine running when checking. Certainly your problems sound like low oil level but it could be caused by a blocked oil filter as much as a low oil level.. The fact it is still pink doesn't mean a whole lot. If its a couple of years old/done 25,000 miles it'll probably want changing, including the filter.

somech

nothing the garage has done im afraid

mikey72

How does the car run, does it idle ok, accelerate ok etc?
Whay year is it?

F.G

Thanks for your replies.
The gearbox oil was changed a year ago, the car does very low mileage.
Its 1996 but drives like new or it used to before it's MOT.
The reason I think it might of been damaged at the garage is because it failed it's smoke test and so will have been revved hard many times to try and get it to pass or because the car was cold when collected by the mechanic and was probably driven hard to try and clear the smoke before it got to the test station.
Either way it's a hell of a coincidence that it's been damaged whilst being MOT'd.
The oil is always checked hot with the engine running.

sp00nz73

its in neutral or park when the smoke test is done so dont think it could have been done during the test. If anything it would be engine damage but they dont need to rev it that hard for the emissions test

Rolandtheroadie

Ok, so how would revving a car (in neutral) affect the 1st to 2nd gear change?
If its been caused by a mechanic that picked it up, it's because it was ready to go and would have happened anyway.
Does an MOT not follow specific instructions for reving the car during an emissions test? They dont "rev it more/harder" to get it to pass?

johnnyroper

scotsman4th wrote: »

Ok, so how would revving a car (in neutral) affect the 1st to 2nd gear change?
If its been caused by a mechanic that picked it up, it's because it was ready to go and would have happened anyway.
Does an MOT not follow specific instructions for reving the car during an emissions test? They dont "rev it more/harder" to get it to pass?

the garage will use a specific method for smoke testing,you will also find mot test centres have disclaimers regarding diesel smoke testing.
but as said the mot will not cause the transmission to play up,it is a coincindence.

F.G

Automatic transmission
When testing vehicles fitted with automatic transmission care must be taken to avoid overheating the transmission system.
Do not carry out unnecessary engine acceleration or prolonged high rewing of the engine. Reference to vehicle manufacturers instruction may be necessary
Recording Emissions Test Results
Record the results of the test Via the VTS Device. (se introduction paragraph 3 at the beginning of this inspection manual)

I found the above information relating to the testing of automatics, why would this info be provided for test stations if there was no chance of the gearbox overheating during the test?

Wee_Willy_Harris

I think you're barking up the wrong tree. The garage have run a fuel additive through the system to clean the fuel system and make the car run as it should. This may be more responsive than it previously was. It may also run much smoother than it did. Both of these factors may lead to a slightly harsher feeling gearchange than before, which will be particularly noticeable between 1st and 2nd. It would require some serious abuse to overheat the gearbox.

F.G

The car runs no differently since having the additive put in apart from the sh!te gear changing of course.
It's the serious abuse bit that worries me!
The mechanic also managed to use £10 of diesel doing about 8 miles.
Serious abuse,hmmmm:(
I know I will never be able to prove anything but I will be taking my cars somewhere else and will also do while you wait MOT's in future.