P51 trannys

[merc-blue]

G'day
I may have come into some RA28 GTV parts, a minimum of a rear end with LSD and a P51 tranny im wondering if anyone knows the ratios so i can double check if its the real deal, also some of the 18RG SSTs
google failed me because all i get is planes

[river]

Hi,

P51 ratios are as follows....

1st - 3.525
2nd - 2.054
3rd - 1.396
4th - 1.00
5th - 0.858
Reverse - 3.755

Diff should be a 2-pinion F series LSD with a ratio of 3.909

seeyuzz
river

[merc-blue]

next question is what they worth?

[jeffro ra28]

They are worth alot!

[merc-blue]

yeah but is it the sorta thing i should put into the car for its close ratios (its a serious hillclimb car) or sell it to someone like river who would hump it regularly for its sexy GTV nature

[jonra23]

Put it in your car (may pay to keep river away from it in public places).

Is there any Celica related facts that he doesnt know?

[river]

Hi,

The P51 design uses synchro-bands (C-bands) instead of your normal synchros. It was built under license by Toyota, as the P51 is obstensibly a Porsche/ZF patent gearbox. A similar box was used in the 911 Porsche in the early to mid 70s. Toyota only put the P51 gearbox into their GT/GTV 18R-G powered Celicas and GT 18R-G powered Coronas from 1973 to 1977. I don't think it went into the RA40 or later Celicas - they got the W50 across the 18R powered range of vehicles. But as the RA40 is beyond 1st gen Celica, I can't attest that I'm 100% accurate on that one. Someone know the answer to this?

They're a very tough steel-case gearbox and mate perfectly to the 18R-G with the 3.909 LSD for good acceleration and nice cruising. The P51 was over engineered for the loads it would take and it was a more expensive box to build than the W50. The W50 can sit behind the 18R-G without a worry and therefore the P51 was dropped.

These boxes are very rare and only a mere handful of parts are available from Toyota - mainly the bearings (which can be got from other sources) and the 3rd gear synchro-band. So, if you break your P51 then it's almost game over, unless you spend the big dollars in getting a gearbox artisan to overhaul it and get the parts custom made for it. Therefore, it's not the type of box you want to break often. Furthermore, I doubt that many, if any, gearbox repairers would have the repair manual for the P51 - unless they get one from me.

How much? It depends on how much the buyer is willing to fork out. As most Celicas, even those with the 18R-G, can be used with the W50 box, I cannot see a normal Celica owner wanting a P51 - unless of course that owner happens to have an original GT/GTV and wants one for originality. Don't forget the W50 will bolt straight into the RA25/RA23/RA28 and RA35 GT/GTV Celicas as easily as the P51, and the gear ratio is close enough for the vehicle to perform just as well as if it had a P51. Furthermore, you can buy W50 boxes, they're cheaper for parts, parts are available and repairers can fix them.

So, you need to ask yourself..... do you offer the price to someone like me for a fair price, knowing it will be used for an original GT, or do you capitalise on the fact that 'cos it's rare you can squeeze as much money out of someone like me?

seeyuzz
river

[airfireman1]

Great info River now I would like to know how you would identify a p51 gearbox if I happened to stumble accross one at a wreckers or bolted to an old import motor.can you please put up details of external differences.
It would be a shame to let one of these slip by, because we did not know how to identify one.
cheers

[river]

Hi,

Rather than duplicate the diagrams, go and check out a previous thread I did with diagrams of the various gearboxs..... http://www.toymods.net/forums/showthread.php?t=4965

You'll notice the W50 and P51 are described together for the outer casing. So, telling them apart is not easy at all. However, I'm sure there must be some small thing somewhere that could assist. I'll check my EPCs 'cos I vaguely remember one of them showing some slight difference between the two. Furthermore, if someone has a W50 and can take a few pics - top, bottom (important), front, back and both sides then I can take some pics of the P51 and we can put them up on a thread and also use it for comparison.

I'd do it, but alas I do not have a W50 box to photograph.

In the interim, I'll check up my EPCs and see if there's anything that stands out between the two.

seeyuzz
river

[airfireman1]

I just happen to have a couple or three spare w50 boxes in the shed, give me a little time and I will take some pics. By the look of the diagrams it will be a chalenge to pick the difference. There must be a few floating around that came attatched to early import motors one would think.
Cheers

[airfireman1]

Ok have pictures of the W50
Cheers

[river]

Hi,

I checked my oldest EPC and it shows that the W50 and the P51 had a slightly different shape from April73 to August73. The main housing didn't have that little ramp/slope towards the bell housing end. However, both boxes had this.

When the ramp/slope bit was introduced from Sept73 onwards, it was applicable to both boxes. So, there's nothing obvious with their shape - they are the same - to help point out any W50/P51 external differences.

However, the retainer is slightly different between the two. However, the EPC diagrams are not detailed enough to show the exact difference. Refer to the following pic....



Notice the circular retainers at the top right of the pic - there's a different one for the W40, the W50 and the P51. Now, that would be about the only way you can tell you have a P51, but it means pulling it out to see. What do you think?

seeyuzz
river

PS: Check the case on your W50 with a magnet. The P51 casing is steel and a magnet will stick to it. If the W50 is an alloy casing I would assume the magent may not stick. Try it on one of your W50 boxes and let us know. That may be the quickest and easiest way to tell?

["Z" UTE]

Question to River regarding the difference between W50 and P51 boxes. I vaguely remember that 1 of the many "W50 boxes that i pulled out of cars had a very different gear lever. Most had the nylon bush on the oily end, however one had a selector which was highly reminiscent of a "T" selector, nice round steel ball without the nylon bush, and yes the diameter of the steel ball and nylon bush was the same.

River could you remove your centre console and pluck your gearstick out, and check the oily end please. If it proves to be different, this may be a quick visual check to see which box is which.

cheers Chuck.

[merc-blue]

So I should buy it keep it in the shed until you blow somthing on yours and you need spares

[river]

Hi,

No need. The spare P51 box also has the selector, and it has the steel ball end. Hmm, I'll check the EPC or my gearbox-diagram thread and see if there is any difference with the selectors.

Thanks for the W50 pics. I'll get some of the P51 tomorrow and put them up.

seeyuzz
river