Tip Trans Computer Change

[tatzoo]

recently purchased a 2001 C4 Cab, turns out the car is a total basket case...

took the car to a local pcar specialist who advised changing the tip computer. 3rd has serious slip under any power conditions. if I shift past 3rd the car wants to go back to 3rd and slips and smells like burning clutch... sometimes the car will flash 4th gear light and "d" light locking it into limp mode until you turn off key and restart car.

I ordered used tip computer, but need to know location of it to swap out the old one to see if its the computer or the actual trans thats bad. From my reading the computer does not need to be programed and should plug and play... anyone have any insight to the location of the tip computer?

Thanks

[Loren]

:welcome:

What were the fault code(s)?

Without them he is just guessing.

I assume he is talking hydraulic control unit (with all the valves)?

If so, then there are two type of units and you need to replace it with a like unit (part number).

[tatzoo]

:welcome:

What were the fault code(s)?

Without them he is just guessing.

I assume he is talking hydraulic control unit (with all the valves)?

If so, then there are two type of units and you need to replace it with a like unit (part number).

Thanks for the welcome and quick response Loren :)

I wish I had the fault codes to share with you, however the pcar specialist who saw the car has yet to return my phone calls to tell me anything or deliver my detailed repair estimate after calling for 2 1/2 days and leaving messages...

All I was told was to start with the trans computer, so I ordered one from specialized german recycling in Rancho Cordova, Ca. I received the computer yesterday and have free time to try and swap it and see if it works. The part I ordered was an electronic computer module or TCU transmission control unit..

Edited September 4, 2013 by tatzoo

[tatzoo]

if anyone has any idea where the unit is located I would be a huge help to have a general idea where to look for it...

[tatzoo]

Loren..

I pulled the code myself this morning P0734 "gear 4 ratio incorrect"....

Any suggestions?

[Loren]

P0734 Gear monitoring, 4th gear - signal implausible

Solenoid valve does not operate despite correct electrical triggering

Possible causes:

- Solenoid valves (Sticking valves, Mechanical damage to pressure regulator 4, Open circuit, short circuit to ground, short circuit to B+)

- Valve chamber

- Transmission

Step 1 - make sure the transmission ATF has been properly topped up (full). Clear the codes and try again.

If the transmission fluid is very old (or black) change it and clear the codes - try again.

[tatzoo]

Loren, are the solenoid valves internal or external?

[Loren]

Loren, are the solenoid valves internal or external?

They are in the pan submersed in ATF.

[tatzoo]

Loren, are the solenoid valves internal or external?

They are in the pan submersed in ATF.

The car just had the trans fluid changed and they put in redline trans fluid, fluid is full, cleared the code and tried to drive it, still a major slip under power in 3rd, but no check engine light. I'm going to change out the TCU trans control unit and see if there is a change. Assuming no change, drop the trans pan and have the valves cleaned, new filter new fluid... no change, Im ordering a used trans on Monday...

[Loren]

The valve body can be changed.

[JFP in PA]

This happens to be from a VW Tiptronic, but the principals are the same:

And this is the actual valve body out of a 996 tip:

[Richard Hamilton]

Is Redline ATF compatible? You have to be careful mixing ATF, as when you drain the system, only about 50% actually comes out. You also have to be very careful filling it, as you should plug in a Porsche tester to monitor the fluid temperature.

[tatzoo]

I took the car to another specialist, took a sample of the ATF... BLACK...I mean black black...

found out the previous owner bought the car with 3rd out of the car and instead of fixing it the idiot just kept driving the car... the clutches in the tranny are toast... so motor and trans came out yesterday...

Next Question...

What should I have them do to the motor to service and preventative maintenance while its out? new water pump? reseal the motor? new drive belt??

Suggestions?

[JFP in PA]

Rear main seal, IMS upgrade, water pump, oil fill tube, 160F thermostat, new AOS at a minimum.

[tatzoo]

Rear main seal, IMS upgrade, water pump, oil fill tube, 160F thermostat, new AOS at a minimum.

I ordered a complete seal/gasket set, mechanic suggested resealing the motor... exhaust gaskets, valve cover gaskets, spark plug tube seals, timing chain seals, cam seals and so on... ordering new water pump, drive belt, thermostat.... whats the AOS?

[JFP in PA]

Rear main seal, IMS upgrade, water pump, oil fill tube, 160F thermostat, new AOS at a minimum.

I ordered a complete seal/gasket set, mechanic suggested resealing the motor... exhaust gaskets, valve cover gaskets, spark plug tube seals, timing chain seals, cam seals and so on... ordering new water pump, drive belt, thermostat.... whats the AOS?

Air Oil Separator, with the car apart, it is a simple install, when together (especially on a Tip car) it is a royal pain. And there are no cam cover (or oil pan) gaskets, they used a Loctite sealant, and there are no timing chain seals as the chains are entirely inside the engine.

[jjb7]

Sounds like the fluid is way low. Just had the same problem. But it should have thrown TIP code 0040. Did the shop know how to properly fill the transmission? The ONLY two aprroved fluids sold in America is ESSO and Pentosin. I used Pentosin.

When you dump the fluid only 3.5 of 9 liters comes out. ZF has transmission service shop in the US.

It is not the TCU. The valve body can be rebuilt. But you may have burnt the 3rd gear clutch pack. There are 7 clutches in the Tiptronic.ZF has service centers in the US.

[jjb7]

Tatzoo,

Sorry to answer this so late. Your tranny was probably low on oil. it slips in 3rd under hard acceleration when low. This happenned to me at the track. Flashing 4th is limp mode. Totally normal. The tranny is trying to save itself.

There is a precise fill procedure, perhaps the shop did not follow it.

Is redline compatible? ZF publishes a compatiblility listing. Use the Pentosin.

Only 3.5 liters of the 10 liters comes out during filter change.

PS: ZF makes most of the shiftable autos today. The 5HP19 series tranny's went into many cars. Getriebe is a subsidiary of ZF.