Trans questions (intermediate to expert??)...

[tsteiner61]

A few fun trans questions for the experienced rebuild guys. All help is greatly appreciated...

1) According to my Chilton's Trans. Manual , the reaction shaft assembly, oil pump housing, input shaft, and output shaft for 727s were significantly changed from the 1973 model year to the 1974 model year (parts not interchangeable). How can I tell the difference? Part #s?? identifying orifices??, shape? etc.

2) Same source says rear clutch piston and Belleville (wave) spring also will not service prior models for same years. Again, how would I be able to tell the difference?

3) Same source says rear servo cushion spring and plug not interchangeable with prior year (73 to 74)? Same question, by visual inspection or part number, how do I tell the difference?

4) Have you ever tried to put 5 front clutches in? Do I need an extra steel as well to do this? My shift kit instructions suggest putting a 5th clutch plate in to get performance type shifts? Whattya think?

5) Where can I get NEW sprag and rollers for an overrunning clutch, also 727? And what is the best way to chamfer them? Can I buy them pre-chamfered?

[tsteiner61]

Have I stumped everyone? No old Mopar tranny techs out there?

[plmczy]

To answer your sprag question. A&A Transmissions sell a bolt in rear sprag for both 904's and 727's. I installed one in my 727, I've had no problems yet. It comes complete w/springs and rollers. Their phone # is (317)831-3066. They can probably answer your other questions.

[451Mopar]

#1) I don't know of any big change in the '73 to '74 years, but the pre 1967 input shaft has a different spline count so converters won't interchange.

#2) Not sure, but I haven't seen the chiltons book, I have severak FSM's and I don't see any difference.

#3) the servos did change durring different years, but if you install a shift kit the kit will tell you how to set it up depending on the servo assembly you have.

#4) I have done the 5-clutch front drum thing, but it dosen't make much of a difference. The Charger with the 451 stroker is just using a 4-clutch setup without any problem.

#5) I think the A&A bolt in would be a good upgrade, I think it costs about $100?

[tsteiner61]

The help is appreciated. Thanks.

The rear sprag is a definite buy, given the fact that I don't want to tear THIS transmission apart anymore.

As for 5 clutches, do they fit with the plates from a trans originally equipped with a 4 clutch setup, or do you have to find one that had 5, like maybe a 904 and then swap? And could you find a flat snap ring for the front clutch drum. I have a Mr. Shift (TransGo) shift kit, and it recommends I do this.

As for the wave spring, I may have put the wrong one in. I noticed a lot (about .150") of end play between the piston retainer, which is splined to the input shaft, and the wave spring in the rear clutch retainer drum, even after the cushion spring is installed in the groove. It's supposed to fit snugly, isn't it?

I think I'm just going to go pull another one and gut it at Pick N Pull. I need some thrust washers and snap rings anyway.

When I'm done, I'm going to post a web page with some helpful hints on this stuff. I let everyone know. Thanks again.

[451Mopar]

To put 5-clutches in a 4-clutch drum you need one extra disk, plate, and an extra rear clutch apply? plate.
To get the extra room for the fifth clutch, you need to remove the old thick clutch plate on the front pack and use the rear clutch plate that is thinner where the retainer ring goes. This is the inside rear clutch plate.
Also if you have a lathe you could turn the front clutch plate outer edges so it sits more towards the rear giving clearance for the fifth clutch. I went to a local transmission shop with my dial calipers and they let me puck out several different thickness of retainer rings for $1 each

The Hemi transmissions came with a special 5-clutch front drum, and I have seen some replacements, but they are really expensive.

[Madness]

I just asked ATI about adding the extra clutch disc & plate. I was told I didn't need it & it would slow the car. I always believed it was needed to increase the transmission's power handling capacity by about 20%.
Also, how about some experienced opinions about using the Torrington roller washers?
Im using a 66 case (727-B) with a ATI rebuid kit, manual reversed valve body, rollerized rear governor support, & bolt in rear sprag. I expect 550-600 hp in a 3400# 64 Spt. Fury. Any suggestions?

[tsteiner61]

Just pulled a second transmission as a parts donor, and I have answered some of my own questions. Thought some of this information might be useful, so I'll share.

Input shaft: Compared a 73 to a 77. There is definitely a difference. The lubrication holes in the front clutch area are in different locations. Both will fit, but I would have to say they are not interchangeable.

Rear clutch drum: I'm glad I caught this or it would have killed my rebuild. In 1974, the wave spring for the rear clutch drum was modified, the new spring has a shorter overall height. Therefore, when using a newer model spring, you must use a newer model servo piston. If not, your endplay at this point will be ridiculous (about .175). When I measured the endplay in the correctly assembled donor, it was .010. This, no doubt would have caused rear clutch apply problems. Doubt it would have moved the vehicle.

Output shaft: Output shafts aren't compatible between 73 and 77 either. In 76, they changed the front planetary pinion tooth angle. It's really hard to notice because and older pinion carrier will fit onto the newer shaft, but not vise versa. I found a good way to check pinion carrier to shaft compatibility is to check the tightness of the carrier to the shaft. A mismatched unit has just slightly more play when doing this.

Hope this is helpful.