1975 P6b Transmission issue?

D

Duane

Member
Hi All,

I am in the process of restoring a P6B that has been off the road for 15 years. Engine seems sorted now (revs nicely with in park), but when you accelerate in drive or reverse, the engine bogs right down to pretty much idle and there is no power. I haven''t touched to transmission at all yet.

Any clues? There is plenty of fluid in the transmission and it looks clean, but it will have been in there for a long time not doing anything.

I assume it is a BW65.

Or am I chasing the wrong thing here?
 
Hi Duane

Doesn't sound like a transmission issue to me. If it was the transmission and it was somehow binding, that won't stop your engine from working hard. I can't see it making it bod down. More likely the engine, as Steve indicated.

What have you changed on the engine so far?

Ron
 
Hi Team,

So I have now confirmed I have a knackered BW65 transmission. I pulled the oil pan off to find very little oil (I'm sure there was oil of the dipstick before I took it for an initial drive, before it stopped altogether), but otherwise very clean with no sign of metal filings, so cleaned the filter and put the pan back in. Refilled the trans with fluid and found I seem to have reverse now (albeit with the wheels off the ground so no load on the drivetrain), but no forward gears. There isn't even a sound when selecting forward gears.
Someone has told me it could be the front pump or a sticky relief valve. The car has was last on the road 15 years ago so likely any seals are knackered at least.

So the box has to come out. Question I have is that the Haynes Manual only seems to refer to the BW35 which says to remove the trans leaving the bellhousing in place. I read somewhere on the forum that the BW65 come out bellhousing and all.

Any tips on the removal sequence would be appreciated.
 
With the wheels off the ground all you could do is load the transmission by trying to drive with the handbrake and footbrake applied, ie a stall test. See what you have then, if you have no forward drive that's normally a failed front clutch. If you have no forward drive but some reverserse it can't be a failed pump because that would affect forward and reverse drive equally. Make sure the selector cable is correctly set. The 65 box has to be removed complete with the bellhousing and converter, and it's heavy.
 
Would anyone know what model or serial numbers of BW65 transmissions would have been used in a P6B. My local club has a couple of boxes but they could be out of SD1s. Apparently the SD1 variant is quite different.
 
Only two series numbers I can find are 013 & 6061 and I can't be certain of those. If you can get pics of the tail shaft housings of the boxes I can tell you what they are.
 
013 serial code for P6B
Anything else is likely to be SD1 ( which won't fit directly without swapping things and or machining things )
 
Thanks guys. Also did some research and found 013 for P6 and 6061 for SD1. Obviously these boxes were used in a lot of other cars too.

Am going to pull the box and take it to a local old school trans specialist to get the original one reconditioned. I don't see the point in gambling on a second hand one that has been sitting in a warehouse for years.
 
I'm sure some cars came with the GM auto, at least out here. but that should be obvious by the label. The Aus BW boxes which I have seen in some P6Bs are built stronger in the drivetrain than the english boxes as they were used on the 4.4 Leyland engine plus similar sized Chrysler and Ford engines.
 
Hi Team,

The transmission reconditioner has come across a problem with the BW65 torque converter. The drive hub splines are very worn so he has asked if I can source a replacement. I know the local club has some BW35 ones in the parts store...are these the same as the 65? 65s are like hens teeth here in NZ. He did say he can cut a converter open and just use the hub if they are the same.

He has had advice that the 35s and 65s are different.

So a) will a BW35 converter fit on a BW65 box

and b) are the specs the same re stall speed, number of splines, shaft diameter, etc.

It is a New Zealand assembled 1975 P6b.

Thanking you.
 
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They are interchangeable.

As long as the 35 converter doesn't have the cooling shroud. Splines are the same.
 
Thanks Harvey.

So presumably as BW65 torque converter from an early SD1 V8 is also compatible? One of the car clubs here has a reconditioned one that could be an option.
 
Hi Guys,

So I finally have the transmission back from the reconditioners (NZD $3300 later), and listed it back into the car this morning. One head scratcher though...this bracket that the selector cable locks into, was not refitted to the box, and I can't figure out which way round it goes.
The selector lever is pointing up (which may be the problem if he refitted it up instead of down), which means that if I fit the bracket to keep the angle straight to the lever it is way too far forward for the locking nuts. If I fit it so the locking nuts sit right, the cable angles downwards which would mean a huge bend to get to the lever.

If the selector lever was pointing down it would probably make sense.

Anyone got a photo?
 

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