Transmission Specialist

[Bellow]

Like a quick thrash around the block at 30 MPH away from the customer gaze and anxiety, and then you shove the bloody thing into reverse a few times to blast the galleries clear & the system internals go into a mechanical "Lahlah land" . Often works as an instant fix.
Of course it was a standard operating test after rebuilds on Borg Warner transmissions in 1970's Jags @100 mph on Gaydon aerodrome & shove it in reverse.
(lovely sound of a Jag 3,8 or 4,2 "blaggers" S types on song unforgettable )
Same with the older Landrover/ Range Rover hydraulic series ZF's , Go from D to R at 30 mph, guaranteed to stir its internal phagocytes & clear it out for smooth shifting .

Seriously - you can select reverse while travelling forwards and it not kill the box? (Genuine question - not sarcasm!)
This is of interest to me not least as I'm shocked that my 4L 80E has no inhibitor to prevent selecting reverse when still travelling forwards - at any speed AFAIK.

 

[Tuercas viejas]

Yes !
In hydro/mechanical boxes the mechanism is built into the design, to allow for inadvertent or deliberate reverse selection when in forward motion; it would be crazy to construct such a fluid style gearbox without it as a feature ! The governor controlled dump of operating pressure takes place so that there can be no speed selection when revere is selected in forward speeds .
In short most of these types traditionally use an hydraulic governor on the output shaft to control upshift and downshift pressure points according to road speed..
Here's an MB example & look for item #680.

722.5 Transmission parts, repair guidelines, problems, manuals

Parts for 722.5: compare prices for Overhaul Kits, Friction Kits, Bushings, Bearing, Solenoid Kits, Valve body, Torque converters, Planetary Gear kits, Filters, Gaskets, Seals, Pressure Plates, Differentials, Sensors, Valves.

go4trans.com

With electro hydraulic boxes as we have today, the speed controls are managed by electronic logic paths so its unlikely you can deliberately select reverse as it with the older boxes.
Tuercas viejas

 

[Bellow]

With electro hydraulic boxes as we have today, the speed controls are managed by electronic logic paths so its unlikely you can deliberately select reverse as it with the older boxes.
Tuercas viejas

GM missed the memo.
On the 4L 80E box there is no inhibition. It's down right scary that there isn't.

 

[Tuercas viejas]

GM missed the memo.
On the 4L 80E box there is no inhibition. It's down right scary that there isn't.

I think you will find that the transmission is controlled by its electronically control strategy as GM puts it.
Its not our usual fare specializing in MB ,L/Rover/Jag and some limited platforms makes like Toyota Hybrids. plus light/medium duty diesels.
But if you want a full or better explanation I can get it from Sonnax
Tuercas viejas

 

[Bellow]

I think you will find that the transmission is controlled by its electronically control strategy as GM puts it.
Its not our usual fare specializing in MB ,L/Rover/Jag and some limited platforms makes like Toyota Hybrids. plus light/medium duty diesels.
But if you want a full or better explanation I can get it from Sonnax
Tuercas viejas

It is a GM 'control' strategy (programmed into the ECU that also controls the engine and with some aspects re-configurable with the correct tuning software) and it beggars belief that there's an (apply footbrake) interlock to prevent shifting out of park but nothing to prevent selecting reverse at any forward speed. This is confirmed by guys who know this transmission well and from my own experience.

Thanks for the offer of asking Sonnax (I'm aware of who they are) but no need. All I need to know is to keep my hand away from the selector when on the move.

I am trying to get the tuning software to work. If it permits inhibition of reverse at speed - it will be worth the effort for that alone.

While I have your attention.... I don't suppose you have a source for good quality brake master cylinder seals for a GMT400 do you? 1.25''bore, I have all the other dimensions also.

 

[Tuercas viejas]

It is a GM 'control' strategy (programmed into the ECU that also controls the engine and with some aspects re-configurable with the correct tuning software) and it beggars belief that there's an (apply footbrake) interlock to prevent shifting out of park but nothing to prevent selecting reverse at any forward speed. This is confirmed by guys who know this transmission well and from my own experience.

Thanks for the offer of asking Sonnax (I'm aware of who they are) but no need. All I need to know is to keep my hand away from the selector when on the move.

I am trying to get the tuning software to work. If it permits inhibition of reverse at speed - it will be worth the effort for that alone.

While I have your attention.... I don't suppose you have a source for good quality brake master cylinder seals for a GMT400 do you? 1.25''bore, I have all the other dimensions also.

Yes I can source it for you but how's about a complete new M/cylinder?
The GMT 400 was in production for about 10 years .
I had a quack scoot about on some web sites and called a few of my suppliers.
Basically most stuff is available.
If you shoot me your vin # to "[email protected]" I will get you some quotes for a kit and or an M/Cyl . (genuine and/or aftermarket)
Cheers Tuercas viejas

 

[ray_hennig]

quack scoot

Sorry sir, can't follow your banter.

Cabbage crates over the briny ...

R

 

[Bellow]

Yes I can source it for you but how's about a complete new M/cylinder?
The GMT 400 was in production for about 10 years .
I had a quack scoot about on some web sites and called a few of my suppliers.
Basically most stuff is available.
If you shoot me your vin # to "[email protected]" I will get you some quotes for a kit and or an M/Cyl . (genuine and/or aftermarket)
Cheers Tuercas viejas

New MCs are easily available but I'm having problems and one suspect is the seals in the Chinese manufactured MCs hence looking for better quality. Two new MCs haven't permanently solved the problem and while they may be the problem, returning them for warranty claim isn't viable due to shipping costs. If I had seals, I could rebuild any of the three (original and two new) MCs I have here.

The problem though could be in the HydroBoost or an ABS bleeding issue. Working through these but having an MC with known to be good seals would help. The Chinese (IMO) do some things well - but not elastomers. I really need something like Girling, Lockheed, etc - and only the seals. The piston just adds to the shipping costs.

They are for the JD7 braking system on a 1999 C2500 Suburban with HydroBoost.. I think GM’s part number for the MC is 18029968. After market MC replacements have part number 390257.

Photo of the seals I need below. Having measured them, I have full dimensions. Most obvious one is they are for a 1.25'' bore MC. If anyone knows of a source in the UK....

 

[Tuercas viejas]

OK
I get the picture with some of the info you have given.
I have access to genuine OE parts so I will give my supplier a jingle and see what they have available
Tuecas viejas

 

[Bellow]

OK
I get the picture with some of the info you have given.
I have access to genuine OE parts so I will give my supplier a jingle and see what they have available
Tuecas viejas

Thanks.
What I'm after is if someone has good quality seals, pop them in an envelope/Jiffy Bag and air mail them to me here - and a method of paying them for that.
Do you want the VIN?

 

[Tuercas viejas]

Thanks.
What I'm after is if someone has good quality seals, pop them in an envelope/Jiffy Bag and air mail them to me here - and a method of paying them for that.
Do you want the VIN?

I might need the Vin#, but I' m familiar with what you are looking for and I don't buy stuff made in China if I can help it. (especially hydraulic brake parts) .
Given me a few hours and I will make some calls.
As for paying I have paytrace etc, being a merchant & auto repair shop.
Tuecas viejas

 

[DSM10000]

Sorry sir, can't follow your banter.

Cabbage crates over the briny ...

R

"bally ten-penny ones dropping in the custard"

 

[Tuercas viejas]

I might need the Vin#, but I' m familiar with what you are looking for and I don't buy stuff made in China if I can help it. (especially hydraulic brake parts) .
Given me a few hours and I will make some calls.
As for paying I have paytrace etc, being a merchant & auto repair shop.
Tuecas viejas

OK I have established that its a special order and I have found at least one in Billings Montana from the Napa auto chain store.
Looks like this.

https://www.napaonline.com/en/p/UBP1737

it would take me about 2 days to get it.
They can't tell me where its made only that its a Napa brand part.

Now on Monday I can chase down factory spec parts from trade wholesalers
Of course the first question that always pops up is why not buy a new one?
Part number M2903

https://www.napaonline.com/en/search?text=m2903&referer=semantic&se=1&txtUser=

From that you can visually confirm if your M/cyl looks like this. (posted for reference only)
Hang tight and I will search some more for you on Monday.
Cheers
T/V

 

[Bellow]

TV. Seals only. If the piston is included, you're right, I'd be as well with a new MC.
As it is I only want to rebuild my existing MCs in case they are the problem - and have them on standby. The problem may lie elsewhere.
If I decide on a new MC I can get from Rock Auto - but a different brand this time.

 

[Bellow]

OK I have established that its a special order and I have found at least one in Billings Montana from the Napa auto chain store.
Looks like this.

https://www.napaonline.com/en/p/UBP1737

it would take me about 2 days to get it.
They can't tell me where its made only that its a Napa brand part.

I think that is a different one from mine (see pic below). I think the NAPA one is what's known as the 'quick take-up' MC as the larger diameter piston (not resent on mine) pushes the pads in before the real braking begins.
The NAPA MC appears to have the large bore section also.

 

[Tuercas viejas]

Then I will need the Vin# to identify the correct part(s) using the OE trade wholesale systems I have at hand in the parts buying programs.
T/V

 

[Fitchy]

Questions for whoever you approach.

I’d ask them do they have a genuine Mercedes Star/Xentry diagnostic system.
Other ‘generic’ systems do not interrogate the systems far enough to always get a reliable diagnosis, nor maybe have access to the latest software updates.

Have they much successful experience of this particular gearbox.

How many miles has it done, and has it had ATF changes done?
How long ago?
How does the current ATF look & smell?
Is the fluid level correct.
Any leaks underneath?

what is the actual problem, (a) difficult to move lever? (b) thumps into gear? (c) long delay in gear changing when selector moved?

once moving are the changes smooth?

all these may help someone give you a steer on what possible causes are.

hope it’s an easy fix

My clk 280s automatic when the engine starts I can't get it to move in drive or reverse any ideas what this might be anybody thanks

 

[Fitchy]

My clk 280s automatic when the engine starts I can't get it to move in drive or reverse any ideas what this might be anybody thanks

 

[DSM10000]

My clk 280s automatic when the engine starts I can't get it to move in drive or reverse any ideas what this might be anybody thanks

Start a new thread after using the search function.

Do not add to an existing thread as you may not get the specific answers you need.

 

[Tuercas viejas]

Well 1st order of the day is to verify the fluid level, then select a gear with someone in the seat and see if the propshaft is turning.
Confirm, that FIRST!
Tuercas viejas