PSI Powerbox. Damage auto box?

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alfaitalia

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I have read on here (and other forums) a couple of times that fitting a PSI powerbox or similar to a DSE can damage or cause wear to the auto box by the extra power generated. Is this true or just biased nonsense put out by petrol drivers and people who have not got PSIs on their diesels!!? How would you know if the box was going to fail anyway even if you had not fitted the PSI. Seems unlikely to me as the power gained is not that great and I assume the box design is similar to the more powerful V8s. Like others opinion and experiences though. Cheers.
 
My auto box failed on mt DHSE at 103K miles, it has had a power box fitted for the last 50K. I think from my investigations that the ZF4HP22 is close to the limit of it's torque handling capability with the diesel. The power band is also unlike the V8 with a turbo induced surge of power at 2500rpm which stresses the one way clutches. Add a remap or a power box and I think it is likely that it will shorten the life of the box. It may of course just be that I'm unlucky that mine has failed at such a low mileage. In the past I have had ZF auto's still going strong at close to 300K miles.
I'm looking at the possibility of eventually replacing mine with the ZF4HP24 that was used for a short time on the 4.6 V8 and which has a higher torque rating. The box is longer but the spacer that connects to the transfer box is shorter to compensate so it looks possible.
 
Datatek said:
My auto box failed on mt DHSE at 103K miles, it has had a power box fitted for the last 50K. I think from my investigations that the ZF4HP22 is close to the limit of it's torque handling capability with the diesel. The power band is also unlike the V8 with a turbo induced surge of power at 2500rpm which stresses the one way clutches. Add a remap or a power box and I think it is likely that it will shorten the life of the box. It may of course just be that I'm unlucky that mine has failed at such a low mileage. In the past I have had ZF auto's still going strong at close to 300K miles.
I'm looking at the possibility of eventually replacing mine with the ZF4HP24 that was used for a short time on the 4.6 V8 and which has a higher torque rating. The box is longer but the spacer that connects to the transfer box is shorter to compensate so it looks possible.
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If its true and it does shorten the life of your gearbox it wont make me take my PSI box off... its just too dam nice to drive with it, and mines done 144,700 miles, but dse boxes are only £250 Second hand, must admit i thrashed the ****e outa mine having fun in the snow.:D
DATATEK did you find out the problem with yours?? or did you just fit your "dog" box.
 
Mike v.t.s said:
If its true and it does shorten the life of your gearbox it wont make me take my PSI box off... its just too dam nice to drive with it, and mines done 144,700 miles, but dse boxes are only £250 Second hand, must admit i thrashed the ****e outa mine having fun in the snow.:D
DATATEK did you find out the problem with yours?? or did you just fit your "dog" box.
Click to expand...

I proved it was not electrical, now I'm waiting for 2 things, the weather to get warmer, minus 3C here at lunch time, and my mate to create a service pit in my barn so I can work on it comfort.
General consensus seems to be that the front overun clutch has failed. When I get it out, my current plan is to see if I can fix it with an overhaul kit. I'm having trouble finding a good reapir manual.
 
Datatek said:
I'm looking at the possibility of eventually replacing mine with the ZF4HP24 that was used for a short time on the 4.6 V8 and which has a higher torque rating. The box is longer but the spacer that connects to the transfer box is shorter to compensate so it looks possible.
Click to expand...

I thought all 4.6s had the 24 box?

Guy
 
Someone will correct me if I'm wrong, but as far as I can ascertain the torque rating of the ZF4HP22 is 300Nm. The max torque of the 4.0 V8 is 250Nm, no problem. The max torque of the M51 diesel is 280Nm, more than the V8 but still inside the gearbox max torque rating. Fit a power box and the max torque goes up to 319Nm, well over the max torque rating of the gearbox. If those figures are correct, it is not surprising the gearbox fails eventually, especialy as there is a surge of power at around the speed the box wants to shift. For comparison, the ZF4HP24 would appear to have a max torque rating of 500Nm.
 
wammers said:
Diesel type 22. Petrol type 24. According to my RAVE. Circa 2000/2001.
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Diesel type 22. 4.0 Petrol type 22; 4.6 Petrol type 24 with a reversion to type 22. I will have to look it up again.

RAVE 2000/01 Workshop Manual Vol 1; Section 44 Auto box description and repair; page 4. This page does not mention the reversion to type 22 for the 4.6, still got to find that.
 
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I just know someone will shoot me down in flames, however, a question that occurs to me is what effect the sport button might have. After all, if a power chip has a detrimental effect on the gearbox surely the sport mode will also. If the sport mode doesn't develop enough torque to effect the gearbox what is the point of it?
 
enery8 said:
I just know someone will shoot me down in flames, however, a question that occurs to me is what effect the sport button might have. After all, if a power chip has a detrimental effect on the gearbox surely the sport mode will also. If the sport mode doesn't develop enough torque to effect the gearbox what is the point of it?
Click to expand...

Sport mode has no effect on torque, it only affects the point at which the box will change gear, in fact on the diesel I have a feeling that changes at higher revs might actually protect the gearbox a little.
 
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