Do i need steelsplined gears in 800 hp, 2800 lbs, transbrake?
Háve anyone with more hp or weight used a standard 3 gear planetary for hundreds of runs?

I talked to Joe at Tranzact about his opinion on the 3 pinion vs 4 pinion planets setup.
He told me that they actually had trouble with the 4 pinion setups. Went back to the 3 pinion setups and the problem went away.
This was in a blown puller application using a 727 making some serious HP...
I

there is one member here who has stripped the splines out of the aluminum ones , forget who it was , maybe he will jump in

got a steel one in mine

more or less you need the steel capped planet because you risk stripping the spline out of the aluminum

I run a 4 gear with a steel hat (splines). We have ran it for about 5 seasons now off the t brake and we are currently pushing approximately 800hp in a 3200# vehicle. I think it is a good idea in your case to run one with steel splines! I think john cope CRT has a 5 pinion that is all steel not just a steel hat added to an aluminum carrier.

I had it happen here to. Found it after an inspection after a rear failure at the line. I put a steel one in and forgot about it.

at 800hp ...yes you need steel.
call protrans and ask Dave

This is a no brainer.
I am gonna order one.

We use stock 3 and 4 gear planetarys in all our trans unless steel is requested.We have logged thousands(yes thousands) of runs in my car and others with no problems.My current trans has been in my 65 for 10 years and seen duty in Curt's 3700# Challenger before that.I personally broke one planetary in all my years of racing,Ron McCelland tore out the splines in his similar trans a few years ago when he broke a rearend(1968 stock set of Dana gears)the only thing hurt was the front planetary.I would rather that happen than have more damage that would have occurred had that been a steel set.

I have an old coffee can half full of gears removed from stripped aluminum front planetaries, and this was in the days when there was only one spline on the output shaft so spline mismatch wasn't the problem.

The factory offered a steel front planet carrier as far back as '66 so it's been a known weak point nearly since day one. Thus the two changes in spline angle to try tp prevent spline failure.

A picture is worth,,,,,,,,the paper it's printed on

Udder side

Post deleted by 540dust

I wouldn't buy anything from Rick Allison ,,,over prices rebuilt stock junk !!!!!!!!!

Hi Moparts,

Doing some 727 work for me/mates, when I realised one of them was a 76 model S/B.
On close inspection I was unhappy with the planetary gear excess play!
I could see from comparing it with an earlier trans that the gear set seemed indentical but the ring gear was different.
Different spline angles and much lower heights as well.
Even so the gear mess was excessive.

Am I right in thinking the ring gear is right but the planetaries has been changed.
I thought the earlier ones do not fit on the later 75-on shafts?

Do the A518 4-5-6 gear planets fit the 76 727 shafts???

many thanx in advance Gtxxjon

Welcome to the board.

There are three different spline angles in the 727 front planetary.

The spline included angles are as follows:

'62-'75= 90°

'76-'93= 75°

'94-on= 60°

The spline angles are sometimes expressed as the pressure angle which is half the included angle (45°, 37.5°, 30°)

Each change affected the diameter of the splines so smaller shafts will fit in larger planetaries but the loose fit will lead to early failure.

Annulus gear diameter is unchanged.