Odd gearbox problem

Hi All,

Well, the gearbox from the crashed SVX has been fitted to my car, and it seems to have been a 1 for 1 swap (no wiring issues).

The problem my mechanic is having is that under load, the gearbox won't change up above 2nd gear - could this be a TCU issue?

He believes that the gearbox changed up through the complete set of gears whilst in the air on the ramp...

To be honest, we're both a bit confused.
Any advice would be greatly appreciated.

L.
--

[Earthworm]

It almost sounds as though the high-clutch is no good in this tranny. It would go through all the gears in the air because there's no load to cause the clutches to slip.

[svxistentialist]

Yeah, a seized clutch would be my guess also.

I presume you have warranty from the scrap yard, but getting your money back won't pay you for the effort of bolting up the dud box. I did advise you it might be simpler to rebuild earlier.

Just to be sure, you should send a PM to Harvey [Down Under], he is an engineer, and well clued up on the boxes. Ask his opinion. Ob Au is his title.

I will check the tranny troubleshooter for you and revert back if there is a simpler routine you can check before you have to bite the bullet and take it off again.

Sorry you are having this trouble Jason.

Joe

[svxistentialist]

OK Laz,

This is what the manual says to check when the symptom is "No shift occurs from 2nd to 3rd gear"

Lower numbers indicate most likely problem, good news in your case:

2: Control unit [aka the TCU ]
22: Control valve
38: High Clutch
43: One-way clutch [3-4]

The last two are inside the box, must dismantle to check or fix.

Ring the dismantlers straight away, tell the guy you want the Transmission Control Unit, or else you will be looking for your money back. It is pretty easy to install, and if the newer TCU works all 4 gears for you, then you're laughing.

Regards the Control valve, I don't know exactly which one they mean here, but Harvey would. These valves are in the gearbox sump, there is a cassette with maybe 6 of them there. The good news is, if the ones in your old box are OK, it is easy to drop the sump, and install your cassette of valves into the new box. Again, if this works, you are laughing.

Both of these things above are pretty easy to do. If neither works, then it will mean a clutch is gone and the box has to come out.

Joe

I would be looking for that TCU pronto!

[oab_au]

Originally posted by Lazarus
Hi All,

Well, the gearbox from the crashed SVX has been fitted to my car, and it seems to have been a 1 for 1 swap (no wiring issues).

The problem my mechanic is having is that under load, the gearbox won't change up above 2nd gear - could this be a TCU issue?

He believes that the gearbox changed up through the complete set of gears whilst in the air on the ramp...

To be honest, we're both a bit confused.
Any advice would be greatly appreciated.

L.
--

Hi mate, you say it won't change up above 2nd gear, What happens then, does it just stay in 2nd and drive along, or does it slip and rev up without driving.

If it is the first, it could be the shift solenoid No.2 won't turn off. This would prevent 3rd and 4th from being selected. it should show a code if it is electrical, won't if it is stuck or jamed.

If it is the second, then the high clutch is slipping or not operating.

Harvey.
Suffering connection blues. 7.2k to-day.