Swapping Transaxles in a SC

[pbs911]

In my apparent never ending quest to do more to my 78SC, I am thinking of moving to a 7:13 R&P transaxle. I've done a search but have not been able to find a straight forward answer.

Can an early transaxle that has the 7:13 R&P just be swapped into my 78SC? Did these come with limited slip? If so, what years/trans numbers came with the 7:13 and which also came with limited slip? Will everything else hook right up (i.e. speedo, halfshafts, shift linkage)? Will I have a problem with the stength of the early transaxle with the basically stock 3.0?

Much thanks.

[addictionMS]

I don't know the answer to your question, because I too have the same question, I have not done any research yet, but one place where I can hepl is it really is 7:31 not 7:13.

I hope this will bump the thread and some one will same me a lot of reading and know the answer....


Jim

[pbs911]

I discovered the 7:31 was only availabe in the 901 transaxles. So it is not a viable option. Oh well so much for relatively cheap upgrades.

[addictionMS]

don't give up so easy, I race with bunch of p-cars here in the Bay Area and many of them are running 7:31 RP in 915s, and if you read Bruce Andersons book he has grear ratios for a 915 w 7:31.

their out there, we just have to find them....


jim

[Early_S_Man]

All '72-'74 915's, and the '75-'76 ROW 2.7 Carreras had the 7:31 ring & pinion gears. The transaxle type numbers with 7:31 would be all 915/08 and lower. None had the sensor for the electronic speedometer, but there are ways to take care of that during a rebuild. Or, you could use an optical pickup trigger mounted externally on the transaxle, and a 'shutter wheel' mounted on one of the CV-joints.

[pbs911]

Thanks Warren and Jim. I thought I had heard the 915's came with 7:31 R&P. I was actually reading BA's Handbook last night and the thought occured to me that it may make for a nice mod since I have a couple drops of blue goo finding themselves on my garage floor recently. Now to only find one.

[Bill Verburg]

The one that is difficult to find is the stronger 8:35 part # 915 302 911 01

I contacted all of the usual suspects w/ regard to this r/p. It was once available but alas seems to be NLA.

[CamB]

Paul

Bear in mind they are also magnesium cased, and may be weaker because of it.

Also, the 7:31 may not be 100% reliable under extended track usage (ask Jack).

If you are rebuilding anyway, as an alternative you could swap in a 7:31 ring and pinion to your current transmission. I have enquired about them before and they are available (reasonably $$$), but worth looking around.

All 915s can be had with an LSD, you just have to look hard enough. An LSd can be added too ($1200-1500ish).

[john walker's workshop]

ok, hot tip here. the '76 912E trans has a 7:31 R+P, along with an electric speedo. now that the word is out, you better get them fast, before they disappear off the wrecking yard shelves. they have the small 901 size mainshaft splines, and 4 cylinder gearing, so you have to pirate the R+P and install it in your 76 and later electric speedo trans.

[Denis54]

What is the price of a new 7:31 R&P?

[82SC]

any one got leads on this mythical 915 electro speedo and low R&P

also how hard is it to convert a early 915 to an electric speedo in terms of cost...and DIY

MJ

[CamB]

For new R&P - I think I once enquired from:

www.phii.net
www.carquip.com

based on adverts in Excellence. Not sure if they quoted me new or second-hand price.

For secondhand, I would try and find a whole 915 with poked synchros. Wayne reckoned you could get 915s for $500.

Obviously buying privately is cheaper than buying new.

Or shortening your 2nd through 4th - $500 per gear please. Plus labour.