1989 740 HPT
Cav (@goodenough)
SE QLD
When it rains it poors!!
First off the gearbox needs help. Hates shifting down to second and overdrive is ok when cold but disengages when it’s warm. Am I looking at a rebuild or replacement? What is everyone’s experience with this?
First off the gearbox needs help. Hates shifting down to second and overdrive is ok when cold but disengages when it’s warm. Am I looking at a rebuild or replacement? What is everyone’s experience with this?
Comments
The od stopping working is clutches heating up and failing, the solenoid usually just will not work. Though it could be the relay but that's a long shot.
That makes sense. The old guy said he cooked the clutch because he turned up the boost or something.
How much for a box?
My mate has an m47 for a 240. Is that a good option and where can I get an extension to suit a 740?
Should not be difficult to extend the shifter bracket of a 240 one.
Haha! I couldn’t part with her just yet.
Just got her up to 140km/h (legally on a road that has a 140km/h speed limit) in 4th gear. The thing hammers. Went to engage o/d but it didn’t engage or maybe I was already going to fast. Didn’t notice much difference. Gearbox is still very usable just hates shifting down to 2nd when going over 40km/h.
I don't know much about the inner workings of the overdrive but from what little I understand high torque / boost shouldn't be applied with the overdrive engaged.
What happens when you double de-clutch? Does it go into 2nd then?
Sheer age and incorrect oil would kill the od clutches.
Just tried that and yes a litttle better!
Yeah I have thought about m90 in the past but what VQ said if I get a dud box I’m back to square one minus 1500 dollars. I might just use an m47 in this one. I’m not looking for really big power. And yeah I’ve heard that the m46 o/d is not a power gear. I can go more than fast enough in 4th anyway haha
Straight forward swap no fekin about.
And being a volvo box no need for engineering approval.
I'm sure the T5 is good for many swaps (and easier to rebuild) but being a rare vehicle I'd keep it all Volvo / M90 if it were mine. I believe the M47 was never used on turbo cars?
Unlikely one of the M90s mported off a parts car was the reason it was taken off the road - however having purchased a couple of these there's no history on mileage so you could get a nice tight one or a very tired unit off a high mileage car, lucky dip. Still worth the chance IMO.
That would suggest that your synchos are worn. Unfortunately M45/M46 synchos are NLA from Volvo, last time I checked anyway.
All is not lost, since Planetman from Turbobricks (Eric at High Performance Auto in Torrence CA) has a supply of them.
For sure. If I go ahead with it I won’t be scrapping anything
Is he sure he cooked the clutch and not the cone clutch in the box? I did a pull in the 245 at 20psi and it ate the cone clutch. Even with a new turbo clutch it still slips in every gear.