What Transmission?

There's a plethora of What Car threads, so how about a What Transmission thread?

Bench race with me for a moment. Say you were using an engine never offered with a manual transmission in RWD form, and it doesn't share a bolt pattern with any other transmissions. However the automatic transmission that came behind it has a removable bellhousing; so it's an adapter plate and mix & match of flywheel (from a closely related FWD version of said engine) and clutch parts from having a RWD manual transmission behind it.

What transmission would you use given these parameters:
- Manual
- Over Drive
- 5 speed OD, 6 speed single OD, 6 speed double OD doesn't matter
- OD needs to be ~0.7 or numerically lower
- Easy to adapt, i.e. removable bellhousing
- Relatively easy to come by, and cheap, think Challenge budget $400 or less, Pick-n-Pull, CL etc.
- Capable of living with 375-400 Lb. Ft. at the rear wheels with minimum/no mods and appropriate to slightly higher levels of hoonage on small but sticky tires.

I discounted the T5 because anecdotal research, everything on the internet is true, shows even a WC T5 won't be happy in the above bench race exercise.

I'd probably be all over a Getrag 265 if they had a better OD and/or I could find one.

The Toyota R series transmissions should work, the R154 looks about perfect on paper, but the RWD 'Yota folks seem to covet them, want lost of monies for them, and they are pretty thin on the ground round these parts. The Truck R150(1) would probably live, but the gearing and OD suck. The W58 has potential, but I'm not sure it'd fair much better than the T5.

A T56 would probably be ideal, but working one into the budget isn't likely to happen short of buying an entire LT1 F-Body to part out, but only being able to recoup $1007.50 (assuming $2015 rules are the same as $2014) will make that quite the feat.

I've looked at other stuff too. The TR3650 looks great on paper, allegedly rated at 360 Lb. Ft., awesome OD, but has an integral bellhousing. There's kits to adapt an SFI bell housing to them but not realistic budget wise.

How bad of an idea is a Doug Nash 4+3? Worse than a T5 probably, I've just come across a few of them cheap-ish.

How about ZF transmissions? As far as I know all the BMW ZFs don't have removable bellhousings. Is there anything besides the C4 Vette's 6 speed that might work?

I'm sure I'm overlooking something. Any other thoughts? Should I just use a WC T5 and keep a couple spares in the garage?

I'm kind of shying away from the grafting of 2 different bellhousings together, or engine block/bellhousing adapters for the moment. I think that adapting the original auto's bellhousing to the transmission is going to be most cost effective and perhaps sketchy but realistic option with my tools/skill set.

That got kind of long...

TLDR:

What manual, OD, transmission with removable bellhousing, that can handle 400 Lb. Ft. and being driven like a teenager, can be had for peanuts?

• Lee

a 4l60e/4l80e and a manual valve body.

RX7 turbo trans?

Or maybe a ZF-5 the ratios prob arnt ideal as it is a truck tranny

Gear:

1. = 5.72 : 1

2. = 2.94 : 1

3. = 1.61 : 1

4. = 1.00 : 1

5. = 0.76 : 1

R Ratio: 5.24 : 1

Yeah, I would guess that most 'murican 5sp early 90's 3/4 or 1 ton truck trans's would meet the torque, number of gears, and removable bellhousing requirements, but not sure they would be reasonably shiftable without a 3 foot lever or weigh little enough to be of any interest.

Maybe something from the mazda b-series trucks?

If you want a cheap junkyard trans, there's always the 4+3 from the early C4s. I've seen one or two show up at the local yard. Who knows? you might get lucky. Also, I've seen T-45s out of SN-95 mustangs work well under similar conditions.

In reply to rcutclif:

The B series (larger engine B series anyway) are the same trans as the RX7 Turbo.

375-400 ft/lbs isn't a problem for a T5, it's the additional 400+ ft/lbs stored in the spinning crankshaft/flywheel assy that's usually the problem. Here's a challenge friendly DIY fix to minimize that, helped me get the power for 1.4sec 60's thru a Saginaw 4 spd...

Clutch Tamer 2 Stage Clutch Slip Controller

Challenge Friendly DIY Version

wvumtnbkr wrote: In reply to rcutclif: The B series (larger engine B series anyway) are the same trans as the RX7 Turbo.

Well then you beat me to it. ha!

I've seen a lot of Fox body guys runs 11's and 12's on T5's, and they don't seem to be sweeping transmission shards off the track after every launch.

weedburner wrote: 375-400 ft/lbs isn't a problem for a T5, it's the additional 400+ ft/lbs stored in the spinning crankshaft/flywheel assy that's usually the problem. Here's a challenge friendly DIY fix to minimize that, helped me get the power for 1.4sec 60's thru a Saginaw 4 spd... DIY clutch tamer

This is sweet. Major kudos to that guy for making one adjustable.

I've seen a lot of t5s bite the dust, but for a challenge car who cares, they are cheap and plentiful. Stick a T5 in it and maybe the diy clutch slipper and go to town. Of it breaks it breaks.

T56 is the obvious answer but like you said they aren't cheap and the plentiful ones in Fbodys aren't super strong, I broke one at a little over 300 at the wheels that is the exception not the rule. Good thing is they are gold and hold their value. Buddy sold a few as cores for 650.

an oe clutch with a little slip can really help drive train parts survive. I broke mine with a pretty aggressive clutch, I know people leaving way harder than me on a less aggressive parts that aren't hurting anything, even the stock 10 bolt

Pretty sure BMW ZF 5 speeds have a removable bellhousing. I didn't remove the bellhousing from mine when I changed the clutch, but it sure looked like it could unbolt.

NV3500 from a 4.3 S10 might work, though that's 3.49 1st, might work ok depending on your rear end gears.

In reply to wvumtnbkr:

This intrigues me, looking at gearing, it could work, some Googeling shows them living behind 500 HP+ spinning triangles, not sure what their torque rating is yet. What's 500 HP spinning triangle's equivalent torque, 35 Lb Ft? There's actually a $150 RX8 6 speed that allegedly needs a new input shaft that's been on CL for over a month. I researched them a bit, but they don't have a removable bellhousing, and seem to have failure prone synchros.

In reply to MrChaos:

Holy first gear Batman. Dad's got an old Scotsdale with an SM465 in it if I need a granny 1st.

In reply to rcutclif & wvumtnbkr:

Can you shed some more light on this? B Series Mazda = Ford Ranger no? My Google Fu hasn't been very successful, assuming it would be from a V6 truck, but the pictures of the transmissions I've seen don't appear to have a removable bellhousing, though I'm not certain that I'm looking at the correct transmission.

In reply to G_Body_Man:

I've considered the 4+3, it doesn't have a whole lot of fans giving it glowing recommendations. The T45 doesn't appear to have a removable bellhousing, I've looked at it, I like the ratios, and OD on it though.

In reply to weedburner & Streetwiseguy:

I've read the entire spectrum, "don't drive like an idiot and you'll be fine," "I make eleventybillion torque powers in my super-turbo 875 big blog with a T5, no problems," "I looked at my T5 funny and it broke," etc. More bad than good for sure, I don't have any first hand experience. See I want to be able to "drive like an idiot" when warranted, and not worry too much.

In reply to Opti:

Basically, I plan to keep the car post competition, and don't want to go through the R&D of multiple transmission swaps. I'm not tripping over T56s at the Pick-n-Pull, and even junk on CL is going for $1300+.

In reply to MadScientistMatt:

I've read it a few places during my search that they aren't, you can trust everything you read on a BMW forum right? Might be like the TR3650 I mentioned earlier, you can remove the bellhousing, but when you do that, there's nothing to support the bearings/shafts on the front end of the transmission. You just wait, you'll get plenty of grief from me when it comes time to Megasquirt this "beast."

If I've missed anybody, it's because you posted while I was writing this post.

• Lee

about the B series. The pre 94 Mazda b series trucks share nothing with the rangers they were badged rangers after 94.

In reply to Kenny_McCormic:

Bellhousing, I looked at the Jeep NV3550 too. I think it would be fine in my potential application power wise though. The Joe Gibbs Silverados had NV3500s behind super charged 4.8ls right?

In reply to MrChaos:

Gotcha, I was looking at later models.

• Lee

I believe the ranger/b series uses an M5OD-R1 transmission in most of the trucks (and manual aerostars/explorers ) and the M5OD-R1HD is in the fancy ranger/explorer model with the 4.0 SOHC. Not a removeable bell housing on the M5OD-R1 (I've pulled them too many times lol) and I haven't seen an HD one but I doubt they have a removeable housing.

Looking at the B2600i transmission, they've got kind of truckish gearing and not that great of an OD.

1st 3.730:1
2nd 2.158:1
3rd 1.396:1
4th 1:1
5th 0.816:1

Actually, I say it's "truckish" but it's got almost exactly the same ratios as the Getrag 265 that the BMW fanboys like so much.

Am I putting too much weight on the OD? The 0.816 would put me at 3300 RPM at 70 MPH in 5th and a theoretical top speed of ~126 MPH at 6000 RPM. Changing rear end ratios would be just one more expense.

In reply to bigdaddylee82:

you could always find a used gearvendors od unit.

Are you gonna run faster than 126 mph in the 1/4? Otherwise the gearing might be a benefit in the challenge at least. Swap to a different gear after if you like.

But depending on you motor, 3300 at 70 doesnt sound bad at all.

You might be able to find a sub 2k lt1 t56 car with problems if you have little time. Saw one last week at 1800, guy said it needed a fuel pump and I saw a real ratty one that went for 900, sold quick though.

Or you could look at the mid 80s and early 90 Japanese turbo cars that aren't loves as much as the gen 4 supras.

Gen 3 supra, Turbo II & 300zx

Seems like the easy button is t5 since they have been adapted to everything and are so darn cheap. If none of the Japanese options pan out I'd probably go that way. I was always told when you put serious traction to them they blow third gear apart, something about them being hung off the main shaft. Put a soft clutch in it and don't flat shift it and you'd probably be fine, the cheapos are even putting them behind ls swaps

I think the 4+3 works rather well. The 4 is just a T10, pretty bullet proof. The O/D is tough, but has to be used correctly. Do not shift under load, push in the clutch like you are shifting the 4 speed. Do not allow it to kick down on its own either. I ran mine for many years autocross and track days, never had an issue.

Downsides are:

1. O/D parts are getting hard to find.
2. The package is rather big and heavy.
3. You'll have to get creative with mounting. The rear of the O/D is built for the Vettes C-beam. There isn't a crossmember.

I like the TR3650. When it was in the V8 Mustangs, everyone acted like they wanted a T56, but in many ways the 3650 was perfect. On a good quarter-mile run, you'll shift it twice and will just be crossing the redline going through the traps.

That doesn't really make much difference for a car you're building, but I did think it was cool how Ford engineered the car as a whole system (and would not have wanted a T56 and the extra shift that would presumably come with it). Of course, one could make the same argument about 4.11 gears...

The TR3650 seemed pretty durable to me. It has a tendency to crash into 2nd if you're un-gentle on a cool morning, but overall it's a smooth-shifting unit. It's far better for clutchless shifting than a T5. I pretty much only used the clutch to start off when I had my 3650, and it never complained or broke.

T5 with a GForce gearset and 9310 output shaft upgrade.....

That will "live" behind 700 boosted hp for awhile. You just need the right clutch.