RS6 C5 Gearbox issues - Help!

[sheffielder]

I'm new to the forum, but have had my beloved C5 for 5 years.

It's done just over 100000 miles and has recently developed the dreaded gearbox problems. My symptoms are the car disengaging during acceleration, revs shoot up, then an awful clunk into gear. Its worse once its warmed up, and under more load (uphill, strong acceleration) Its worst 3rd to 4th, but also seems confused 1st to 2nd and back to 1st in slow traffic - the clunk is there but just not as marked as the speed is so slow. 2nd to 3rd and 4th to 5th are still perfect.

TBH, symptoms have been there for a bit of time. It clunked just once a number of months ago, then no more problems for a while. Then did it again and eventually started doing it more often. However, its not doing it all the time and I have learnt how to drive it carefully to minimise the symptoms. Strange thing is its actually got better recently, but I only drive it for 10-15 minutes at once and only very carefully, and I know if I put my foot down, it will jolt into gear again, which tends to bring on the symptoms for another week or so. I don't understand why it's inconsistent and not problematic all the time, or why its got better, and wonder if its more likely an electronic than manual problem.

Obviously the time has come to bite the bullet and get it fixed. I want to sell it once its done, but i want to be able to say to a buyre its genuinely fixed. I've read a lot of the posts already on here about it, and have seen there's various problems it could be, eg just ATF fluid or pipe, or more serious things like torque converter, EGT or Oxygen sensors, valve body. I don't want to pay a fortune to get it fixed if it turns out its just a fluid issue (there is a small oil leak but I can't identify exactly where it is coming from, and come to think of it there was a similar small leak a number of months ago which seemed to clear up without a defintie fix, so i don't know if that may be linked). However, if it needs the full works, I want to get it sorted.

It sounds like Grizz at Unit 20 is top of the list to go to, but any advice, recommendations welcome.

Cheers

[amanda1]

I have bitten the bullet and had my gearbox fully strengthened by Trans 517 in America ..... Not cheap but mine is a keeper

Link here

http://www.517trans.com/catalog/11a.php

[chunky79]

Either go to Unit20, MRC or put it up for sale saying it needs a new box. That way the new owner can decide what to do. 517 is really only needed for modded cars.
Oh, and FON.

[RustyBucket]

Some people on here have had a result from having the fluid and filters changed and in addition to MRC and Unit 20 there was also a guy on here who used AMD in Essex http://www.amdtuning.com/product.detail ... eID=167585 and was delighted with the result. Where are you based?

[Keaney]

Yip, take to MRC or unit20 for a gearbox service. Might fix it, otherwise they might be able to tell you if the clutch packs have went... You will however still need to pay for the filters and service etc etc

Worse case scenario gearbox refurb 5k+
Best case gearbox service £300ish

Good luck, depends if it's a keeper to go through the pain. Personally I'd sell it before getting it done if you were going to but it would need to be at a reduced rate

[sheffielder]

Cheers for all input. Rustybucket, I'm in Northampton area.

Would a gearbox service identify for example a cracked ATF pipe? If so, I think I'll sort out where the current leak is from and try a service first.

Is it really possible that the serious clunk gearghanges (and slight delay before gear engages at slow speeds) could be down to a cracked pipe and leakage of ATF?

[Nobby]

To check the level the car needs to be brought upto temperature and the fill plug removed. If a tiny bit leaks out then the level is ok.

When the ATF is serviced the oil will be drained which will remove possibly half of the oil - there will be some left in the remaining passages of the gearbox and torque converter which is harder to drain. MRC might have tools to do this fully though. Remove the sump pan and replace the filter (which will show the tube which can crack) and check for any swarf inside the pan indicating wear to parts such as the clutch packs or casing etc.

General ATF colour and smell should indicate whether it is burnt or not too - it probably won't come out crystal clear anyway. Similarly if its black, thick and sludgey then its not good news.

An ATF leak shouldn't really happen from that many different places. There is obviously the sump gasket, the sump plug and drain hole (would be fairly obvious is the leak was from there), the feeds lines to the cooler and the cooler itself. All other leaks would likely be engine oil or DIFF oil such as rear output seal and driveshaft seals.

[sheffielder]

Mmm

There has been a real burning smell just in the last few days after a short (10 minute) drive. I wasn't sure whether it was the leaked oil as its heated up or linked to gearbox problem!

[ahoooga]

Don't mess around, any element of doubt suggests you should get onto MRC at Banbury and get their expert opinion.
Edited due to originally replying on a phone

[RustyBucket]

A quick blast down the A43 to MRC is your best bet and the chaps there to have a look

[jimes256]

mine was leaking as i think someone had reused gasket on sump. also found they had not used an o ring between strainer and gearbox! new oil, o ring, strainer and gasket and all is fine. theres a guy in bristol who is mustard on these gearboxes and will fix with maximum bill of under 2k depending on the fault. Alex 07791493915

[bilko1]

Mmm

There has been a real burning smell just in the last few days after a short (10 minute) drive. I wasn't sure whether it was the leaked oil as its heated up or linked to gearbox problem!

When my rear output shaft seal was leaking I got the burning smell but that is not ATF fluid. Also if your cam cover gaskets are leaking this normally drops on to the exhaust manifold giving a lovely burning smell to.

[Weiß-sechs]

I personally love the smell of burning Quantum 5W30

[mavada]

Mmm

There has been a real burning smell just in the last few days after a short (10 minute) drive. I wasn't sure whether it was the leaked oil as its heated up or linked to gearbox problem!

When my rear output shaft seal was leaking I got the burning smell but that is not ATF fluid. Also if your cam cover gaskets are leaking this normally drops on to the exhaust manifold giving a lovely burning smell to.

mine smells to, but only after giving it the beans...

[Shoppinit]

Are you talking about your car or your ass?