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4 speed transmission questions

9096 Views 47 Replies 13 Participants Last post by  oppositelock
I am having a 4 speed rebuilt. I have new synchros and a full gasket/seal kit. Does anyone have a source for shift forks or do I have the worn areas on the forks brazed and re-machined? This is for my racecar so any other advise would be appreciated.

Also The shop that I use for all my tranny work has a Vega transmission that is fully rebuilt already with all new bearings, shift forks, synchros... It has been on their shelf for at least ten years (still bright inside) It was offered to me for $350 plus the labor to swap one of my Opel output shafts and tailshaft housings. Should i buy this for a spare?
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i thought it was the chevette trans that was the same
but if it fit id get it and you could prob tak them down because whos gonna build a vega

If it is the early Vega transmission BUY IT!!! If you don't I will. There are some differences between the Vega and Opel, but at $350 for a new transmission you can't go wrong.

For those who don't know. The early Vegas had Opel 4 speed transmissions. I think that the only difference was the input shaft was made to fit the Chevy. Many years ago I bought a "How to Hotrod Your Vega" book. The book has a detailed section on rebuilding the "Vega" 4 speed. I used it... and still use it today... all dog-eared and greasy... for rebuilding Opel transmissions. If you cross out the word Vega in all of the detailed pictures and instructions you can't tell that it isn't an Opel.
I bought one in a salvage yard once, installed it in my Manta only to find out that the drive shaft wouldn't go in the tailshaft of the tranny.

So, they are the same except the tail shaft is larger.

the vega trans probably has the same shaft size and the auto trans which is the same as a th350 and a 700r4
when i switched my powerglide out for a 700r the drive shafts splines where the same

i wonder if Stan still has that Quaiffe 4 speed you might want to check with him

also the quaiffe gear set comes with a steal synchro in third gear. that would be a great help steal synchros that is

The Quaife 4 speed has a great set of ratios... far better than the Getrag. (In fact for racing the Getrag ratios are awful... it's a "cruiser" transmission) Also, the Quaife Opel gear set is not strong enough for a high HP engine. I put one in my F-Production and it only lasted 4 races. So that means that it won't stand up at something over 150 HP. It would be great for an ITB car, but unfortunately... not legal for ITB.

I am going to try to figure a way to convince SCCA that the "sport transmission" should be allowed in ITB. I have some German documentation, and I'm digging through all the old articles to see if I can find more that shows the "sport" gear ratios. If anyone has original test articles or other documentation that shows the ratios, let me know. For you ITB folks, a word of caution... the Quaife Opel gear set costs more than a complete Quaife "rocket" 300 HP gear box.

By the way, we use Quaife gear boxes in all of our race cars. If any one is interested in it for the Opel, we can fix you up. It is not for the "faint of wallet", but if you want the perfect gear ratio for your car, the Quaife is the least expensive... and maybe the only way to get it for an Opel.

Peter (or anyone else looking for a stock 4 speed),

The OGTS does have good used 4 speeds. They went through and tested a whole bunch... actually swapped transmissions in and out. So they have all been road tested.
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i might be the only one but i have looked at the richmond six speeds and they are very strong and sompact enough for the gt this is the route im taking
TGSI, I have quite a bit of vintage articles, and some Opel specific magazines. Can you tell me what you are looking for and I will dig thru and see what I might have.

The Richmonds are very strong and have a good selection of gears. Our first approach after Quaife Opel gear set "gave up" was to go with a Super T-10. But there are some problems for the Opel. First, all of the Richmond transmissions (T-10, 5 or 6 speed) are too long. The total length of the Opel transmission is about 14" and the Richmond is about 22". With a 1" adapter plate, this means that the shifter will sit back about 9". (the driveshaft would have to be about 9" shorter too). If you can live with the shift lever moved back 9" then it would be OK.

Another problem is that they are wider and with the shift linkage, you will have to "massage" the transmission tunnel to get it to fit.

From a performance stand point there's good news and bad news. The Richmond is designed to take the HP of a high HP detroit V8. It will handle up to 450 ft/lb of torque, so you'll never break it with an Opel. The bad news is that to take that HP (torque) it has to be heavy. It weighs over 100 pounds, and most of that extra weight is in the gears and spinning mass. That's like adding about 25 pounds to your flywheel.

You will also have to have a cu$tom input shaft made... or at least have the one that comes with the Richmond re-machined. Since they are designed for Ford, Chevy & MOPAR V8s they won't work with the Opel... not just the splines of the clutch plate, but also the input shaft length and crankshaft pilot bearing are wrong for the Opel.

Last, the Richmond street gear boxes (5 or 6 speeds) cost about $2K, but by the time you are done with all the machine work and adapters, you will spend twice that... unless you are a machinist.

If you can overcome the obstacles/drawbacks, then you can build your engine 'till you hearts content. How about a Wipple supercharged Opel 2.7L CIH engine putting over 400 HP to the ground in a 2000 lb Opel GT.
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I am looking for any printed information refereing to the "sport" transmission and their gear ratios. I would be particularly be interested in anything that mentions a "sport" transmission as an available option. I think the sport transmission was an available option in Europe, but I have nothing that says it was available in the U.S.

Proof of an available option in a magazine test will probably be sufficient to SCCA. I think I have enough other gear ratio documentation on the "sport" transmission gear ratios, but mention of specific gear ratios along with mention of the "available option" will be even better.

Any original Opel materials would be best of all.
well i realize the size thing and linkage but those as well as the input are things in the r&d stage
the clutch center splines are simple to over come the linkage and shiftercan be placed wherever to fit right and i would find a used unit because of the custom work that would need to be done
also i was thinking a t5 might be a good choice they have a larger gearing selection and they use the s10 input aswell
they also have some with shifter sitting way back on the tail or in the center the internals will interchange to an extent betwen the chevy and ford models
Bob how much for a Quaiffe gear Box?

i wonder if it would be possible to get the steal synchros made for the Opel Trans

For an ITB racer that would probably be a good investment.

an ITB Opel probably wont see 150HP unless they are using a 1.5 Head ha ha

Once i herd of the T-9 setup for the Opel i but out a request to my friend back in TX to get me one out of a Merkur XR4TI (they have a big old Pick-N-Pull) it took like a year but only cost only $65

after i finally got the trans i found out you could no longer get the adapter Doh! so it just sits

72opelguy I ran a T-5 on the street for several years came out of an 87 S-15 2.5.
I think Rally Bob mentioned that a few 5 speeds would work in a GT. Man i was off and running after that looking for that 5 speed setup

I thought the T-5 worked great but i am the only one that thinks that way. then again John Curry is the only one that ever drove my street GT (rode like a buckboard)
the Getrags where running $1500 at the time

the T-5 was $450 (wanted to make sure i got a good one) adapter plate was $110 drive shaft was $40 (to get it cut down the Opel auto drive shaft was free)
the drive shaft was so short it could not be balanced

the T-5 is heavy sucker also i would guess 70lbs or so.
i did not know you could mix and match gear ratio's i love the .72 overdrive

I think the quaiffe T-9 setup would be the way to go if you can stay away from quaiffe USA the price would be cheaper also.

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Anybody know if a WC T5 will bolt to a NWC bellhousing? I'm dreaming of decent ratios and a really tall 5th so I can drive on the highway again....

The little info I've been able to find on the 'net seems to indicate that it might work.

The Quaife Rocket transmissions cost from $1450 to about $3000 depending on which transmission you go with. But then there's another $1000 - $2000 for everything to wrap around it (machine work and bell housing adapter, mounts, driveshaft, etc). So you can figure on about $3500 to get a "bolt in" set-up for and a synchro gearbox. If you want a real race (dog) transmission then figure on $5K for a bolt in.

When I say bolt in, I mean bolt in. The swap is easier than a Getrag swap. (At 3 to 5 times the cost, it had better be) Note that this is for a 4 speed not a 5 speed... but with perfect gear ratios.

If your question was about what the close ration Quaife Opel Gearset costs (to use in an Opel transmission), the last time I checked it was about $2700. You get about the same gear ratios as the Rocket transmissions, but overall they are not as strong.

As you can see... unless you are racing to win, or make over 200 HP, the Getrag is by far the best deal. And it is the only other "bolt in" solution I know of.
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I don't think a WC T-5 will work 1 inch 10 spline.

I've been on the lookout for stuff for the T-5 and if my quaiffe goes out again i could bolt in the T-5 and do what we always do drive around the problem

The Opel quaiffe is just a blast to drive, going up through the gears was like my GPZ 750 I used to have.

Bob i would be very surprised to see a non GT4 spec Opel 1.9 putting out 150HP very surprised

So that we are all the same page the Quaiffe rocket box is a T-9 with a Quaiffe gear set in it right, hope I don't have my info screwed up.

this Trans is very popular in England with the Ford rally racers so that's why quaiffe offers so much stuff for it

The Merkur XR4TI has a t-9 trans in it but its considered weak so they (the US XR4TI crowd) like replacing this trans with a T-5.

The quaiffe T-9 case is big bucks but if you had your own case you could save a lot of money by buying just the gear set
and i would go with a synchros straight cut 5 speed setup like my quaiffe 4 speed.

there was a company in England that offered an adapter to allow you to bolt up a t-9 to an Opel

Bill Davidson has one and he let John Mills us it in his GT4 Manta

i asked Bill last year if i could have the specs on the adapter plate He said yes but they where not be taking the box out just for that, but when they took it out they would get the info

So there might be away to spend a lot less money but all the ducks have to line up.

my gut felling says the T-9 Adapter plate will look just like the T-5 one (the XR4TI people like replacing there T-9's with T-5's)

Bob we got get you to spend less money ha ha

another money saving tid bit quad TB's for a Toyota and this one is high since its new

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davegt27 said:
I don't think a WC T-5 will work 1 inch 10 spline.
Getting a clutch with a different spline is the least of my worries. Besides I'd run an aftermarket 26 spine shaft anyway....

Bob i would be very surprised to see a non GT4 spec Opel 1.9 putting out 150HP very surprised

Hmmmm.... I was just on a Dyno last Saturday with my car and if I hadn't gone extremely lean at 5500 rpm due to stock fuel lines and pump I likely would have hit 150hp, 145hp at the least and with a very FLAT wide torque curve. That's with a 38 DGAS on a modified Opel intake and '75 exhaust manifold. Not exactly GT4 spec...

I'll get the fuel issue sorted out soon but I don't know when I'll have easy access to a dyno again. I was in Canada last week.

yes there are a large variety of gearsets fopr the t5 ford and gm used them in alot of different setups gm behind 4 and 6 cyl and ford had them behind a few rangers i thinkand 6 and 8 cyl stangs
there are other cars out there that have them to i think the only difference in all of them is the inputs and outputs but for different gearing they also used a different counter shaft so for perfect gear a new one might have to be machined but they is a good selection out there
i know ford changed around several times
i will see if i can find a chart of gearing available and what they come in because i want to get on because i have a street opel nmow and want as much mpg as possible
Gee.... I have a T-5 from a mid '80's S-10 sitting in my shed. I picked it up when I was planning a V-6 GT project. Dumped that idea when I picked up the '51 Olympia.
should have the right input for the clutch but it also might have a 26 spline dk came with either
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