Ooo transmission..

Themoog2 · Post by **Themoog2** » Tue Sep 14, 2021 12:31 pm

Well well.. Ive noticed a gear shift problem over the last week on the Zf24 5hp on the 4.4
On gentle acceleration there is a sort of lag changing gear followed by a slight thump as it changes.
Im not sure which gears its between (I think 3 to 4) but all the others are ok.
More aggressive on the throttle and its OK as is the manual shift and even sport mode non manual.
It doesn't do it all the time and I don't get that lurch everyone talks about when stopping.
Could a solenoid be to blame?
What do you think chaps? Fluid / filter change to begin or has anyone had this symptom and can enlighten me?
It shows no codes on my c113 scan tool but that doesn't mean to say there are some stored that it can't read. I may get a proper scan on it.
I hope it's not a major job as I've just decided to keep the car after hunting all over the place for a Cayenne..
Get your ideas in.

henrym3 · Post by **henrym3** » Tue Sep 14, 2021 9:47 pm

First move has got to be oil and filter. I know the proper stuff is expensive but if you don’t use it you’ll always wonder if it doesn’t fix it would the proper stuff have worked

Themoog2 · Post by **Themoog2** » Tue Sep 14, 2021 10:28 pm

Well it's had Comma MV ATF plus in it for 5 years and I've done it twice.
Ive been researching and what I have can be a symptom of low atf so yes it will be a service first.

X5Sport · Post by **X5Sport** » Wed Sep 15, 2021 8:28 am

Low fluid certainly worth a check as it's all gears. Could also be (if not all gears) sticky solenoids as the system uses 'overlapping' the transfer the load smoothly between gear sets - one clutch opens slowly as the second on closes at the same speed. If one of those solenoids is a bit 'sticky' then the smoothness of the overlap gets a bit thumpy....if that makes sense.

When my first box (6 speed) was rebuilt there was an issue where the overlap wasn't right and the engine speed would pick up before the new gear was fully engaged - a bit like clutch slip on a manual box. In that case the issue was found to be in the Mechatronics unit and it had to be replaced. I don't think the 5sp has that unit and the servos are all repairable/replaceable individually.

As you say, service first, then delve deeper.

There is a gearbox specialist at Biggleswade - A1 Premier Transmissions - if that's of any use. Not cheap, but they know their stuff. They've rebuilt two of mine and even found the fault in the E46 box that BMW denied wasn't there - dodgy baulk ring on 2nd - so it now drives properly.

Themoog2 · Post by **Themoog2** » Wed Sep 15, 2021 2:28 pm

I know A1. There's one even nearer to me at Baldock and I was there less than a year ago as I thought my torque converter was knocking (which turned out to be the vanos) and the engineer there said that the 5hp24 is a really good trans as long as they are serviced at least every 50k.
Job for next week then..

Themoog2 · Post by **Themoog2** » Thu Sep 16, 2021 5:48 pm

Arrgh. I'm getting mad now. I did a full lock reverse to the right yesterday and noticed that the front n/s driveshaft was clacking like crazy so a new on of those is on the cards too.

Themoog2 · Post by **Themoog2** » Sat Sep 25, 2021 5:30 pm

Ok here we go..
Ive done a full trans service today - fluid and filter. Did the test drive and the thud from 3 to 4 is gone as far as I could tell on that short trip.
The gear changes are all smooth as now but...
When i took the sump off I found some chunks of metal stuck to the magnets.. Not a good sign. See photo.
The magnets had a bit of fur on them but nothing major. Fluid was dark red and didn't smell too bad.
When i refilled it and ran thru the gears in manual it would not stay in 4th.
1,2 3 and 5 all ok.
Anyway, its all back together but I may be living on borrowed time although it's driving ok.
We will see.

Themoog2 · Post by **Themoog2** » Sat Sep 25, 2021 5:32 pm

Oh, and another thing..
I could twist the driveshaft as though the transfer case chain is slack - is that normal?

X5Sport · Post by **X5Sport** » Sat Sep 25, 2021 9:40 pm

That’s not good! At least they’re caught by the chip collector magnet and aren’t on the loose in the mechanisms now, but….. 4th gear uses the A & B clutch packs only so these could be from the drums around those clutches rather than the clutch material as the size and shape looks like part of a drum. Sadly I think you’re right, chunks of metal are not a good sign. Some images of parts here….I did look to see what might be a close match to the source of the bits.

https://www.automaticchoice.com/en-gb/b ... -catalogue

The only way to find out is surgery

Leslie · Post by **Leslie** » Sat Sep 25, 2021 10:51 pm

Trouble ahead by the looks of it

Themoog2 · Post by **Themoog2** » Sat Sep 25, 2021 11:18 pm

I've sent an email to Stevensons engineering near Ware to see what a rebuild will cost but in the meantime there is nothing I can do but use it.
Who knows - there may be chunks of metal in lots of gearboxes on cars that the owners know nothing about..
Like I said, 4 th gear was not selectable as I was cycling through the gears after putting fresh fluid in but when I drove it all gears were usable.
What about the transfer case chain apparent slack? Thoughts anyone.

Leslie · Post by **Leslie** » Sun Sep 26, 2021 9:41 am

The transfer chain will always have a bit of slack when the miles stack up if it's driving ok when going slowly from lock to lock in a car park I wouldn't worry about it.

X5Sport · Post by **X5Sport** » Sun Sep 26, 2021 10:03 am

Themoog2 wrote: ↑Sat Sep 25, 2021 11:18 pm Who knows - there may be chunks of metal in lots of gearboxes on cars that the owners know nothing about..

The scary thing about that is you’re probably right. It’s why aircraft have warning circuits on their chip detectors…..OK the consequences tend to be a smidgin more serious when their gearboxes go……but it’s only a sensor that brings a warning light on and the magnets are already there anyway.

Themoog2 · Post by **Themoog2** » Mon Sep 27, 2021 2:02 pm

I've been going about in it today with no probs. Smooth gear shifts.
Quote from Stevensons is between £2009- 2509 + vat depending on parts required.. Hmm

X5Sport · Post by **X5Sport** » Mon Sep 27, 2021 7:56 pm

Ouch. Hard call given the age of yours, but if it’s running OK at present just enjoy it. From memory, a big chunk of that is the labour. I think A1 used 18 hours to remove, rebuild and replace. The cost (without the Mechatronics Unit) was £2,200 in 2008 on a 6sp ZF. Came with 12 month warranty and a full gearbox service after 1,000 miles.

BMWs quote was £7k +VAT for a remanufactured (not new!) box. They didn’t, and still don’t repair them. The current 8sp box for my X6 is almost £13k for parts alone (new). Add a day’s labour @£200/hr and ouch! Even the clever rear diff is around £10k (new), and this is why it still has a warranty on it.

XSeries-forum

XSeries-forum