TH350 Drive-shaft Yoke fits (or doesn't) a Getrag 240 (was "Mystery solved!")

[BQS4]

I just dropped off a GT 4-spd driveshaft, along with an automatic yoke to be made over for a 5-spd conversion, and while there, the guy behind the counter said that the auto yoke looked familiar. He said it looked like a STOCK GM TH350 yoke, and to prove it, he pulled a new yoke off the shelf, and went and got a TH350 output shaft and it slid PERFECTLY into both, I watched as he did it. Sooooo, in the future, with auto shafts running dry, here's the proof positive that you can get a new one off the shelf.

[neuropel]

Has you confirmed that the TH350 yoke works on the Getrag? I thought it was Bill Hoffman and/or Gary that confirmed this would not work? I remember this thread...

[David McCollam]

Gene,

The illustration you gave about the fit is absolutely correct and undeniable! An automatic yoke from an Opel driveshaft will fit on a TH350 output shaft.

However, when you put the the TH350 yoke on the Getrag you will need 3 pound hand sledge and a lot of luck. It will not fit! There is a minute, i.e. the difference between metric and English measurement for the spline width, difference. It will allow an English to metric fit, from metric yoke to US output shaft, but not the other way.

I had a transmission shop use the same logic on me and I spent an hour and a half attempting to get the TH350 yoke on the Getrag output shaft. It never worked.

Dave

[anastosmotors]

Dave is correct. Bill H. try to fit the 350 yoke on the getrag output shaft and did not fit properly. I did not work.
Pete

[RallyBob]

I agree with this as well, I worked on a car that had a Getrag tranny with a TH350 yoke fitted.

I had to hammer the driveshaft to get it out of the tranny...there was NO slip fit. All the fore-aft motion was occurring at the torque tube spline into the rear axle!

[BQS4]

Well, I can't argue with this many people, except to haul the getrag to the driveline shop and borrow his TH350 yoke. But, why wouldn't the output shaft from a TH350 not jam when slid into the Opel auto yoke? I mean, he slid it in and out with two fingers (all you nasty minded people hold your thoughts, especially you Roy) if the yoke from the 350 won't go on the getrag, wouldn't it be the same the other way around? He did mention that there were several different types of the TH350 yoke, but, I didn't get the number of the one he pulled out.

[BQS4]

Alright, just got off the phone with the shop, and got them to give me the number off the box that had the GM TH 350 yoke. It's made by NEAPCO # 3R-3-6081X with an internal "C" clip

[BQS4]

I'm not trying to prove anyone right or wrong here, but, just to settle some questions, mostly mine, I will take the trans with me when I go to get the modified GT drive shaft, and no I didn't get them to install the TH350 yoke, I just want to get a picture for future reference, and I won't force the TH350 yoke on the trans, I just want to see for myself.

[Anonymous D]

Experience has shown that although the OD seems the same (when simply eyeballed), that only a high-mileage TH350 driveshaft may fit correctly (a new shaft is too tight and won't fully seat into the trans, due to tolerance variation of about .00025" in the splines).

[blancojp]

Originally Posted by BQS4 I'm not trying to prove anyone right or wrong here, but, just to settle some questions, mostly mine, I will take the trans with me when I go to get the modified GT drive shaft, and no I didn't get them to install the TH350 yoke, I just want to get a picture for future reference, and I won't force the TH350 yoke on the trans, I just want to see for myself.

The TH350 yoke does not fit well and has to be hammered in after the first 10mm travel. You can either find a 5-sp BMW and remove the driveshaft or buy an after market unit from this place:

Automatic Transmission Accessories

I have dealt with them in the past and they give fast service on all orders. You can also find this part in your local RICE shop since the conversion is very common on the Toyota Supra and other japan made RWD cars. Hotrods use the 240 or 265 as well when coupled to a 4-6 cylinder engine.

I might be able to get my hands on a few pieces.

[Gary]

Gene - I heard in the exact same thing about the GM yoke when I had my GT driveshaft welded.

The GM yoke does not fit the Getrag.

I think the answer is in the machining of the Getrag. There is a radius or bevel in the splines in the Getrag tailshaft that the GM yoke does not have.

[GTJIM]

If the TH350 yoke is too tight but can be hammered on this merely means that there is a tiny bit too much metal somewhere that interferes with the sliding fit. Too much metal means that it can be removed - with a diamond coated needle file if necessary. The big problem only occurs when there is too little metal as putting tiny bits on is heaps more difficult.

If the interference is at the root of the splines then the corners may need to to eased off the internal ID of the spline inside the yoke. It can certainly be made to fit - that is what engineering 'Fitters' do ...

I made a Jaguar MkII 3.8 yoke fit into an R11 Borg-Warner overdrive unit by turning down the OD - the internal splines were the same. Got the near new overdrive unit for $100 because no one could find a yoke - sold it for $2,800 with the made-to-fit Jag Yoke! It went into a 1951 Lincon that had a blown unit and destroyed yoke ....

[dallasmanta]

so no one mentioned the Chevy Vega as an option.

If memory serves me well the early Vega 4 speeds had a larger output shaft on the back of the Opel transmission to handle the added engine torque, I remember a shop telling me that the 4 speed Vega yoke was the same as the Opel automatic yoke. Never tired this but always wondered. Ron

[Bill Hoffmann]

I have to weigh in here. As stated by previous posts, the THM350 yoke will not fit the Getrag. Yes, it's the same number of splines, and the same diameter, and indeed the Opel automatic yoke will fit a THM350 spline and vice-versa, but the THM350 yoke will not fit the Getrag! The reason is the shape of the splines. One is rectangular and one is trapezoidal. Believe me, I spent hours with a needle file trying to make it happen. It won't.

Bill

[blancojp]

Originally Posted by Bill Hoffmann I have to weigh in here. As stated by previous posts, the THM350 yoke will not fit the Getrag. Yes, it's the same number of splines, and the same diameter, and indeed the Opel automatic yoke will fit a THM350 spline and vice-versa, but the THM350 yoke will not fit the Getrag! The reason is the shape of the splines. One is rectangular and one is trapezoidal. Believe me, I spent hours with a needle file trying to make it happen. It won't. Bill

Then I believe to be safe than sorry, buy the correct part from a retailer and be done with.

[itb gt]

I have a vega trans in one of the race cars,I had to have a drive shaft made. If it helps I can give you the part numbers.If it helps Jim

[GTJIM]

Must be an Inch/Metric thing as the Opel TH180 autos were made in the (old!) GM Transmission plant in Strasbourg, France - probably metric specs.
Whereas I guess the TH350 Yokes were made in the US of A (or Mexico!) to inch specs .. and probably with different techniques.

Now, Suzuki used TH180 autos right up into the 1990's so I wonder which specs they used? After all they were part of (old) GM before it became 'Government Motors' recently.

The other possibility (Nihil Desperandum) is to make a broach from a hardened section of Getrag spline and use it to machine the interfering bits out of the TH350 yoke - if the 'real thing' can no longer be found.

[BQS4]

Originally Posted by GTJIM The other possibility (Nihil Desperandum) is to make a broach from a hardened section of Getrag spline and use it to machine the interfering bits out of the TH350 yoke - if the 'real thing' can no longer be found.

Jim;
This is why I'm trying to something else to work. Even though the Samuri/Trackers used the TH180 trans, majority of those were manual trans, so the automatic yokes are getting in the "harder to find" range.

[RallyBob]

Maybe we need someone with good access to a junkyard to go on a walkabout and gather up some driveshafts from other vehicles that have used the TH180. I know they were used in Opels, Chevettes in the US, Fiat Spiders, Samurai/Trackers, and US postal delivery vans.
I have heard rumor they were used on at least one model of Volvo as well. Any other applications I don't know about?

[BQS4]

Well, I didn't get to try the TH350 yoke, as the shop was swamped with truckers trying to get their rigs back on the road, so, I just got the shaft I brought in and left. (Yes I did pay for it, total $75) But, Bob's right, we need to get a good comprehensive look at what can substitute for the Opel auto shaft.
BTW, Doraville Drivelines does great work....

[blancojp]

Originally Posted by BQS4 Jim; This is why I'm trying to something else to work. Even though the Samuri/Trackers used the TH180 trans, majority of those were manual trans, so the automatic yokes are getting in the "harder to find" range.

Gene:
According to my Master replacement guide, the yoke from a 2002-2005 Cadillac CTS 5-spd will fit the Getrag 240 transmission. It is also used on the 2004 Holden (new GTO) and the early (1999-2001) Volvo C-70. They are easy to find and should be available in a few U-picks and Ebay. I have located a few (14) at several retailers and verified fit information above, they are after all widely used on Hot Rods when a 4-cyl is installed. I have two complete Getrag 240's and three yokes in stock however they are all spoken for. I also have two complete Opel auto transmission drive shafts and three incomplete.

Let me know if there is any interest since I will be in the area next week were the parts are at.

[blancojp]

To further the info line on the transmission, I got this from a factory BMW Engineer:

"BMW does not use yoke in reality for the Getrag. It has a 3 bolt flange on tailshaft that bolts up to something called Guibo; which is a rubber doughnut that has 6 holes, 3 for transmission and 3 identical sized for front end of drive shaft. The splines are similar as those of a GM auto transmission and with a little tampering and elbow grease, you might be able to use a GM yoke on it. You used something similar on the Silver series Rolls Royce which coupled the transmission via shaft to the center bearing. Cadillac also uses the same yoke/shaft on the smaller models with manual transmission but I believe it is a 260 model and not the 240. The Getrag 240/260 has become a very popular upgrade on 4WD trucks and Japan made RWD vehicles like the Supra. You might want to try a few of the clubs or if you really need to use a yoke on your application, all 6 cylinder Jaguars from 1979 to 1985 using the GM200 auto transmission have a usable part. I will send you a drawing, usage chart and the tech notes on the 240/260 transmission as soon as I get to the office."

Right from the horses mouth, can't beat that!

[GTJIM]

Originally Posted by blancojp all 6 cylinder Jaguars from 1979 to 1985 using the GM200 auto transmission have a usable part. I will send you a drawing, usage chart and the tech notes on the 240/260 transmission as soon as I get to the office." Right from the horses mouth, can't beat that!

So, I wonder if the all the TH200 auto trans uses the 'Getrag' type spline as many GM used that trans in 'light-duty' use - worth checking to see if the TH200 yoke is different from the TH350 spline.

[Lindsay]

Originally Posted by GTJIM So, I wonder if the all the TH200 auto trans uses the 'Getrag' type spline as many GM used that trans in 'light-duty' use - worth checking to see if the TH200 yoke is different from the TH350 spline.

Two different length of yoke for the 200R4 transmission, (4.5 and 5 inch long) What is the Getrag yoke length?

Note: 200R4 yoke is the same 27 spline yoke used on aluminum Powerglide, TH350, 700-R4, Muncie, and Saginaw transmissions. But, the 200R4 is considered GM METRIC, automatic transmission.

Previous commet would be the best selection:
Master replacement guide: the yoke from a 2002-2005 Cadillac CTS 5-speed will fit the Getrag 240 transmission. It is also used on the 2004 Holden (new GTO) and the early (1999-2001) Volvo C-70.

[GTJIM]

Originally Posted by Lindsay Two different length of yoke for the 200R4 transmission, (4.5 and 5 inch long) What is the Getrag yoke length?

I was refering to the predecesor of the four-speed TH200-R4
- the TH200 three-speed that is an uprated TH180 design.