Pinging those who know auto-boxes.

Your right foot and over 300bhp, you crazy scouse!

(c:

On or around Mon, 18 Feb 2008 23:27:49 +0000, Douglas Payne enlightened us thusly:

I'm afraid I might have to agree... if it's the ZF 4HP22 I'm not sure it's rated for 300 bhp.

Badger's the expert on these, though.

Sounds terminal, almost as if some of the clutches are well worn down to bare metal!

At a guess, your engine.....?

And I reckon a V8 with a turbo is probably more than 300lbft, not to mention the rate at which the torque increases as the turbo(s) spool(s) up....... Basically, your autobox just isn't designed to cope with the abuse it's been getting fed...... have you considered the early rangie 3-speed autobox? Needs the right transfer box to give a decent top speed/rpm but it's a bloody strong box the old chrysler torqueflite. Badger.

On or around Tue, 19 Feb 2008 17:47:07 -0000, "Badger" enlightened us thusly:

I wondered about that. is the ZF 4HP24 rated any higher?

the other 'box I've heard is tough is the GM 400, dunno what sort of job it'd be fitting it though.

It would be a right pain in the arse but is certainly possible, but if I was going to that effort I'd be using the GM 700R4 which is the 4 speed evolution of the TH400. They cope happily with 450+lbft of torque in their standard form.

I managed to get another ZF4HP22 off ebay and I'm going to fit it and cross my fingers for now. The GM Torqueflight option does sound like it could be a plan.

I take it the ZF transfer box won't fit the GM auto.

The gearbox was most probably killed when we were setting up the engine, the ZF box takes badly to the engine being revved whilst in neutral I later discovered. The original box lasted 107k miles, and the replacement has done 48k miles so I'm hoping I might not have to replace this one for 40-50k.

Other thing, how much is a GM box + transfer box likely to cost me?

Nope.

Transfer box in neutral, autobox in "D", handbrake on. Saves all the "A" clutch wear........

Pass, never dealt with them. Be aware though that the TH700R4 someone mentioned has a history of lock-up issues, and a common mod in 'Merika is to inhibit the lock-up. TF727 fits straight to your engine and uses an LT230 transfer box, just a pity it's a 3-speed though. Badger.

Did you hear that noise then? The slapping one? That was my hand hitting my forehead at high velocity. Why the hell didn't I think of that?

It's got the torque to pretty much ignore the number of gears...