L322 L322 Gearbox Reverse Problem please help

Bemble said:

Okay Tony, I've got your address and I'll email you. You might want to delete your email address from your post now so that you don't receive loads of spam.
Phil

Click to expand...

Ok Phil,

Look forward to ur mail

Tony

Tony Kerr said:

Ok Phil,

Look forward to ur mail

Tony

Click to expand...

Hi,
I have exactly the same problem with my L322, TD6, 2006 with 140,000 mile.
Did it turn out to be a Seal in the C Clutch circuit? And can you tell me what the ball park cost was to get this repaired?

Thank you,
Paul.

Bemble said:

If you select 1st gear in manual (steptronic) mode do you get engine braking? (showing that the F-clutch is working properly)
If so, it does sound like you have an internal leak in the C-clutch circuit, which unfortunately would mean that the transmission would have to come apart to fix it.
Phil

Click to expand...

Hi, albeit quite an old thread, but what would be the conclusion if there is no 1st gar engine braking?
Thank you in advance,
Tomo

For the ZF 5HP24 transmission, if the vehicle doesn’t move in reverse and there’s also no engine braking in Manual 1st gear, then the F-clutch/brake is faulty.

Phil

Bemble said:

For the ZF 5HP24 transmission, if the vehicle doesn’t move in reverse and there’s also no engine braking in Manual 1st gear, then the F-clutch/brake is faulty.

Phil

Click to expand...

Phil,
thank you very much for the reply. Would you be able to advice on the following problem and how to sensibly proceed?

- The car: L322, 2006, TD6 with GM5L50, had transmission rebuilt done by previous owner 4 years/40,000km ago (probably w/o changing or upgrading the valve block)
- The problems/symptoms: No 1st gear engine braking, reversing uphill gave "trans failsafe mode", and accelerating from standstill seems sluggish, else seems to drive ok,
- IIDTool error codes: LCM-Light Control: 0x59 Transmission emergency program fault ...and ... TCM-Transmission GM: 0x20 Output shaft speed sensor fault: General fault
- What I understood so far: valve blocks seem notoriously prone to leakage, thus burning up the clutches, and that the above failure codes don't tell much (at least to me)

Well, from here I don't know how to proceed, because I still don't understand the most likely cause of failure. Would a valve block swap/upgrade suffice? Would it make sense to do that first and if problem still exist have the tranny rebuilt. Any test I can perform to narrow down the problem?

Tomo
PS: a sonnax.com page lists one cause of "loss of reverse at high pressure" as "wear valve body cross leak"...that is the thin hair I'm clinging to....

The common factor would appear to be the Low & Reverse clutch as it provides engine braking in 1st gear and is also used in Reverse. Its function is to ‘earth’ the inner race of the Low Clutch sprag.





The clutch receives its hydraulic pressure from the Reverse Lockout Valve. I wonder if it might be worth removing the valve body assembly and checking both clutch feed holes with air pressure to see if the seals have failed?





Phil

Bemble said:

The common factor would appear to be the Low & Reverse clutch as it provides engine braking in 1st gear and is also used in Reverse. Its function is to ‘earth’ the inner race of the Low Clutch sprag.
The clutch receives its hydraulic pressure from the Reverse Lockout Valve. I wonder if it might be worth removing the valve body assembly and checking both clutch feed holes with air pressure to see if the seals have failed?
Phil

Click to expand...

Phil,
again thank you. Am I correct to understand, that if I air pressure test both feed holes they should hold a certain pressure, or in other words there may be no air cross flow? Which would confirm tight seals, thus no problem there, which would point back to a leaky reverse lockout valve in the valve body?
Cheers

Yes, exactly.
Phil