Druken

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WackyRotary

I can't advice about the 79-80 tranny or S5. Never seen one actually to compare. But a 81-85 5spd can be compatible with S4 n/a for sure by removing the tail housing and swapping.

79rx_7

Can anyone tell me if the 79-80 tranny is different from 81-85. I realy want to swap to a S4 or S5 GXL tranny which has the best gearing for fuel economy I think

Stock 79 gears: 3.647 - 2.218 - 1.433 - 1.00 - 0.825
S4 or S5 GXL : 3.476 - 2.002 - 1.366 - 1.00 - 0.697

This tranny only came on the second gen 87-91 GXL

Rogue_Wulff

The trans will physically fit, with a couple minor issues.
1. The shifter is about 4" further rearward on the FC (86-91) trans compared to an SA (79-80) trans. The FB (81-85) trans shifter is about 2" rearward of the SA. This will require modding the floorboard and console.
2. The trans mount is different on the FC trans. You will either need to obtain an FB tailshaft housing, or fabricate a custom crossmember to mount the trans.

Felgar

Quick question for the guys who've done this...

When removing the S4 tailhousing, how did you seperate the housing from the front of the tranny without removing the block from the end of the shift rod?

For my S3 tailhousing the block was just held on by a bolt so I took it off then slid the housing over the shift rod. But the S4 block is held with a roll pin which is a problem esspecially with the tranny half taken apart. Any ideas?

(if I punch the roll pin through it looks there might not be enough room in that little enclosure, and I was also unable to verify that the shift rod is drilled all the way through)

renns

Felgar,

I just disassembled one a few days back, and it punches out no problem. The FSM shows it clearly as well.

Jeff20B

iTrader: (13)

So you just tap it all the way through?

renns

Jeff,

If you remove the other bits as shown, you can knock it straight through. Also, check you PM's

Jeff20B

iTrader: (13)

So it's a little more complicated than the FB bolt type, but is doable. Thanks!

trochoid

iTrader: (6)

The pin is not hard to knock out, but the orientaition must be right to get enough clearance to push the rool pin all the way out. If not, the pin hits the wall and stops. Flat bottom drift works well, a pointed on jambs the pin.

Felgar

Yup, understood. Thanks guys.

caddy83

I need an SE tranny but very difficult to find. Parts for rebuilt are not all available. Who can post up the most recent write up to install a 2nd gen non turbo tranny into a 1st gen SE. Turbo 2 tranny to much modification. Need a simple 2nd gen swap. Anyone in the Los Angeles Area done this swap. Need help. Thanks

Rx-7Doctor

iTrader: (13)

You are looking at the thread that answers your question. The S4 Non-turbo transmission with the listed tail shaft swap is a direct bolt in. Remove old transmission, perform swap and install.

Is their other information that you need besides this?

The S5 non-turbo transmission is not a direct bolt in.

caddy83

Thanks RX Doctor? S4 non turbo trannies are from what exact years of a 2nd gen. rx7. These trannies are readily available, correct? Where can I have an S4 tranny rebuilt? Or an 85 SE tranny rebuilt near Cerritos, CA. Who can do this modification for me(L.A, CA area). Any recommendations of an affortable rotary mechanic.

trochoid

iTrader: (6)

S4, 86-88. Parts between the SA and any 2nd gen tranny are no compatable, parts from the S5 are not compatable with the S4, when swaping tail housings. What may be confusing people is the terminology The tail housing is the rear 1/3 of the tranny case/body. The shifter housing is the part that bolts on the top of the FB and newer tailhousings, which is the part that positions the shifter location. Section 7A of the FSM has a complete teardown and rebuild guide for trannys. I suggest that all those asking questions read and familiarize yourselves with that section.

caddy83

Section 7A of the FSM where can I find this. I'm not familiar with this search forum. Help

trochoid

iTrader: (6)

Link for the online FSMs is in my sig. Download the 85 and 87 manuals as they are the most extensive manuals for the S3 and S4 models. The 87 manual covers mostly the TII tranny, which is quite different than the NA one. There isn't much difference between the FB and FC NA trannys, but some of the differences make swapping parts incompartable. The bearings in the S5 NA tranny don't allow for the tailshaft swap with the earlier NA trannys.
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locopr1

I think I understand this but need a point of clarification. If I take an S4 trans, add an FB tail housing, will I need to cut the floorboard on my SA and if so by how much? Also, what flywheel and starter would you use? I imagine 2 inches rearward is where you woulde end up?

caddy83

WHo can rebuilt my S4 tranny and my SE tranny? I live in cerritos, CA. Need help

locopr1

Find a quality trans rebuilder. Rebuilds are EXPENSIVE. Old car trans rebuilds are MORE expensive, they know they got u over a barrel. But for the expense u are better off finding a reputable person on this site and buy it used.

trochoid

iTrader: (6)

Use the SA flywheel, starter and clutch. There may be a differenece in the number of teeth between the S4/SA starter, if so you may need to use the S4 starter. You may not have to cut the tranny tunnel at all, but the shifter will be a tight fit on the rearward end of the hole. You may have more trouble with the shifter boot and cover plate than anything else. I have not done this particular swap, so don't hold me to the tunnel clearance issue.

mpk490p

will my S3 clutch slave work or do i need to swap for a S4?

Hyper4mance2k

iTrader: (40)

s3 slave works. I've done this swap twice now. I love the huge 5th gear.

mpk490p

sweet thanks, in which case i have everything i need! looks like a nice easy swap

Jeff20B

iTrader: (13)

I've done the swap too. The taller 1st didn't bother me at all using an RB aluminum flywheel on a 12A.