741 Upgrades for a 716 transmission

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JERRY LANDES
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741 Upgrades for a 716 transmission

#1 Post by JERRY LANDES » Tue Jul 05, 2016 2:21 pm

I'm getting ready to rebuild a 716 transmission that came to me with the later throw out bearing. I faintly remember someone telling me once that there other upgrades found in later 741 transmission like the shift rails or the selector that I might consider doing.

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Re: 741 Upgrades for a 716 transmission

#2 Post by Jon Bunin » Tue Jul 05, 2016 3:49 pm

Jerry,

If this is going into an A car with stock shift linkage, you cannot use 741 shift rails or selectors in the transmission.
The 716 is a 356A transmission. Make sure that you don't confuse an early 741 as a 716, as Harry Pellow and others have done. The transmission type is stamped into the bottom of the maincase.
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Jacques Lefriant
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Re: 741 Upgrades for a 716 transmission

#3 Post by Jacques Lefriant » Tue Jul 05, 2016 6:07 pm

depending on the year 741s had a stronger 1-2 fork, a thicker 1st gear, a 12 bolt diff, needle bearings in 3-4, idler shaft lube mod, bushing in idler locked
 

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Re: 741 Upgrades for a 716 transmission

#4 Post by JERRY LANDES » Tue Jul 05, 2016 7:33 pm

Now I remember Jon, We had a conversation some time ago about transmissions. I thought at the time that you were talking about 716s vs 741 but maybe you were talking about early 741s vs later ones. We bonded over a transmission that you built for my S90 roadster that I sold to Aziz in Davis. He drove us both crazy! That transmission was done perfectly and drove great.

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Al Zim
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Re: 741 Upgrades for a 716 transmission

#5 Post by Al Zim » Fri Jul 08, 2016 10:18 am

I believe that the engagement teeth that are attached to the pinion shaft gears are slightly longer on the 741 transmission. This would enhance the "hold in" of the gear to the operati9ng sleeve. If you are installing a C transmission it would be best to use the reverse gear shaft from an earlier transmission that has the trough for the oil. This can be identified by not being circular. Use a strong Locktight on the bushing in the reverse gear idler. Clean the gear with either (starting fluid) and let the Locktight seep into the gear around the bearing do one side then the other. Read your shop manual, good luck al zim
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Re: 741 Upgrades for a 716 transmission

#6 Post by JERRY LANDES » Fri Jul 08, 2016 11:42 am

Thanks guys for the information. I have another question since Jon suggests that the 716 and 741 are different. Can I put a 741 4th C gear in my BBAB 716 to make it BBAC. I have a friend that has done this with a 741 with good results. My motor with its modifications should work fine with this set up. I do like the A third gear ratio.

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Vic Skirmants
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Re: 741 Upgrades for a 716 transmission

#7 Post by Vic Skirmants » Fri Jul 08, 2016 12:20 pm

You can put the 741 4C in your 716 trans; BUT. What is the trans serial number? You mentioned BBAB gears. The conv Ds that were built with BBAB gears still used the 644 gears. The ones built as real 716s used the 716/741 gears.

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Re: 741 Upgrades for a 716 transmission

#8 Post by JERRY LANDES » Fri Jul 08, 2016 12:57 pm

Vic, Although the trans # is 23379 which according to my spec book falls in the 644 group not only my COA says that its a 716/2 (under options), but it says that on the transmission. I believe that the spec book is off which has been known to happen. Now your opinion in my experience has always been correct so what do you think? I'll probably be calling you to buy a 4th gear so we would have been going through this discussion anyway. Interesting enough I have a 59 coupe with the exact same production completion date of 02/18/59 as the Conv. D but its transmission is # 26114 and says 716/1 on it. That's 2,735 difference. Now its motor #73038 and the D's is 73094 which is only 56 numbers off!

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Re: 741 Upgrades for a 716 transmission

#9 Post by Vic Skirmants » Fri Jul 08, 2016 7:51 pm

Yep; the good old conv D trans conundrum. 23379 is a 644. You need a 644 4C.
26114 is a 716; different synchros; same as 741.

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Larry Coreth
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Re: 741 Upgrades for a 716 transmission

#10 Post by Larry Coreth » Sat Jul 09, 2016 3:25 pm

Vic,
Are you saying that a 716/2 (as stamped) and since it is also stamped with BBAB gears means the it has 519 gears in it, like a 644? Or did I misunderstand ?


Jerry
Secondly since you are planning to rebuild said trans and step "A" after removal from the car is to pull the intermediate plate with all the gears attached, One glance at the synchro ring of any of the 4 gears will tell you what kind of gears you have !
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Vic Skirmants
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Re: 741 Upgrades for a 716 transmission

#11 Post by Vic Skirmants » Sat Jul 09, 2016 5:32 pm

The 716/2 would indicate it should have 716/741 gears in it.
However, the serial number puts it in the series that still used the 644/519 gears.
Jerry; what is the casting number on the left side of the housing: 644xxxxxx or 716xxxxxx?

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Re: 741 Upgrades for a 716 transmission

#12 Post by Larry Coreth » Sat Jul 09, 2016 8:52 pm

I suspect a miss-reading of the serial # !
Jerry , are you sure it is not 25379 or even #26379 ?
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Re: 741 Upgrades for a 716 transmission

#13 Post by JERRY LANDES » Sun Jul 10, 2016 9:34 am

Since the transmission is a couple of hours away let me get back to you guys after I can take a closer look at it. I know for sure that the COA says 23379 and I'm pretty sure that I checked that number when we first took it apart 10 years ago. I'm going to take a couple of pictures just to confirm what is going on here. I do remember 716/2 on it but I don't remember if it had the gear ratio also stamped on it. I should know by the end of the week.

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