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The input shaft and low ratio countershaft assembly out of a donor T-18 can be swapped into the T-18 to make a low ratio or 6.32 1st gear Transmission . The ford input shaft is shorter with a different diameter spline and nose diameter. You can get a different pilot bushing for the crank to allow the ford input shaft to work.
I think the difficulty you are having is that you are trying to replace the input shaft on a Jeep specific T-18 with the 4:1 ratio. The Ford input shaft only works with the low ratio countershaft. The input gear must mesh with the drive gear on the countershaft.
You can probably find a ford T-18 in a Transmission boneyard to get the parts. If you want to keep the original Jeep input and the 4:1 ratio, I have a set of these parts leftover. The 6.32:1 ratio is the way to go if you can get the parts.
There are several sites on the web about this T-18 work. You may want to contact PartsMike.com for info and some parts. He is a good resource. Also Novak conversions has a good website for info and parts.
Well I guess I am assuming now you do have a Close ratio ( 4.02 low) Jeep T-18 that you wish to convert to the 6:32 low gear? As Johnbilt has mentioned to get to the 6:32 Low gear the Input & Counter shaft has to be changed.........and that's where it gets sticky between the Jeep & Ford versions although both built by Borg Warner and some parts do interchange.
The 6-1/2" length Ford input shaft for the 6:32 has 17 teeth and 1-1/8" x10 spline (so if you make the swap you need to use a Ford Disc.)........the correct counter shaft that goes with the 17 tooth input is a 43-36-27-16 There was also some difference's in input shaft Bearing size that I remember running into between the Jeep & Ford versions Although I believe Novak makes a bastard input shaft that somehow fixes that.
Also I'm thinking maybe the First/Reverse sliding gear may also have to be changed to a 40 tooth if it does not already have one in there.
I remember years ago playing with a Jeep T-18 could have even been a T-98 and were successful in making a 6:32 Low gear version out of a 4.02 but we had tons of parts scattered on the bench and several donors Transmission gear sets to work with. Sorry memory on this stuff is cloudy!
Novak in Utah would be a good one to call.............see if you can talk to there Gear Guy in the back..........I think his name is Brian..........works with this stuff daily. Smart Guy.
Lets forget about everything except the first paragraph.
you have replaced the input shaft and countershaft assy in a jeep T-18 with a wide ratio ford input shaft and counter shaft and ended up with a 6.32:1 jeep transmision with a short input shaft.
That is teriffic!! I have not heard of this being done before and I have not found any web pages discussing it. Was your jeep T-18 a CJ or J-10 Transmission ?
If I could replace a few parts in my close ratio and end up with a wide ratio with a Dana 20 on it rather than buying an adapter for a Ford truck T-18 to mount a Transfer Case it would be a very cool thing.
The input shaft and low ratio countershaft assembly out of a donor T-18 can be swapped into the T-18 to make a low ratio or 6.32 1st gear Transmission . The ford input shaft is shorter with a different diameter spline and nose diameter. You can get a different pilot bushing for the crank to allow the ford input shaft to work.
I think the difficulty you are having is that you are trying to replace the input shaft on a Jeep specific T-18 with the 4:1 ratio. The Ford input shaft only works with the low ratio countershaft. The input gear must mesh with the drive gear on the countershaft.
You can probably find a ford T-18 in a Transmission boneyard to get the parts. If you want to keep the original Jeep input and the 4:1 ratio, I have a set of these parts leftover. The 6.32:1 ratio is the way to go if you can get the parts.
There are several sites on the web about this T-18 work. You may want to contact PartsMike.com for info and some parts. He is a good resource. Also Novak conversions has a good website for info and parts.
I have performed this on two different T-18 's. The first was a long input shaft version out of a J series FSJ. The second was a 1976 CJ7 factory T-18 4:1 Transmission .
FSJ Version: I modified it to install in my 73 CJ5 . I swapped in a short ford input shaft, which mated perfectly with the existing gearset and bearings in the T-18 . I matched the clutch disc splines with the input and installed the larger pilot bushing. I think the Ford is 1-1/16" diameter. The Jeep input shaft version is 1-1/8" with a larger nose and slightly longer.
76CJ Version. I tore down my 76 CJ T-18 for a rebuild and discovered it was a 4:1 ratio. I found a donor ford T-18 at a local Transmission shop minus a top cover. I swapped the input shaft and countershaft gear to complete my Jeep T-18 . I don't recall if I had to swap the 2nd and 3rd gear units on the mainshaft. The 1st gear and reverse unit were the same. The overall ratio change is controlled by the input gear and countershaft speed. The smaller input gear drives the countershaft at a lower speed and therefore produces a lower gearing across the gearset range, except 4th gear. The 4th (final) gear slider drives the mainshaft directly and produces a 1:1 output, regardless of input shaft gearing.
Novak is a great resource. I've done two of these. Novak has done thousands. They will know all of the different configurations.
I am guessing you used a ford disk with the Jeep pressure plate?? what clutch did you use that is 10.4 inches in diameter, or whatever the jeep is??
Parts mike does say that this is possible and that the counter shaft would need to be replaced, Novak on the other hand seems to suggest that you shy away from the jeep T-18 all together.
the part number for the jeep bearing set and the ford bearing set are different, was there a problem with the input shaft bearing in the swap??
At this point I am wondering how interchangeable the parts are from ford to Jeep and how much creativity this gives you in gear combinations.
I have performed this on two different T-18 's. The first was a long input shaft version out of a J series FSJ. The second was a 1976 CJ7 factory T-18 4:1 Transmission .
FSJ Version: I modified it to install in my 73 CJ5 . I swapped in a short ford input shaft, which mated perfectly with the existing gearset and bearings in the T-18 . I matched the clutch disc splines with the input and installed the larger pilot bushing. I think the Ford is 1-1/16" diameter. The Jeep input shaft version is 1-1/8" with a larger nose and slightly longer.
76CJ Version. I tore down my 76 CJ T-18 for a rebuild and discovered it was a 4:1 ratio. I found a donor ford T-18 at a local Transmission shop minus a top cover. I swapped the input shaft and countershaft gear to complete my Jeep T-18 . I don't recall if I had to swap the 2nd and 3rd gear units on the mainshaft. The 1st gear and reverse unit were the same. The overall ratio change is controlled by the input gear and countershaft speed. The smaller input gear drives the countershaft at a lower speed and therefore produces a lower gearing across the gearset range, except 4th gear. The 4th (final) gear slider drives the mainshaft directly and produces a 1:1 output, regardless of input shaft gearing.
Novak is a great resource. I've done two of these. Novak has done thousands. They will know all of the different configurations.
Please understand that I am providing my personal experience and that I would never attempt to mislead or give you bad information on purpose. I have been successful with both of my Jeep T-18 's. Not sure why Novak would prefer to steer away from the Jeep units. It is probably true that the Ford units are more consistent and that the Jeep is the oddball unit in the field. My situation is that I had Jeep T-18 's to work with, so that is what I used.
The pressure plate is a standard Jeep part. In my case, I have a 73 AMC 360V8. This is a 10-1/2" plate which bolts to a standard Jeep flywheel. Mine is a 3 finger Borg and Beck style. Throwout bearing is standard Jeep part.
The pressure plate is a matching 10-1/2" clutch disc with a Ford 1-1/16" spline. The hub dimensions and all else appear to be the same as the Jeep 1-1/8" unit.
The pilot bushing is a special part. It has a different outer diameter and inner diameter from the standard Jeep/AMC part. 1) The inner diameter is bored to fit the Ford input shaft. 2) The outer diameter is larger which fits into the large recess in the crankshaft. It provides a bearing surface for the shorter Ford input shaft. These are available from Partsmike and I think they are in the 4WD hardware catalog also. I have bought several and they are readily available.
Both T-18 units that I used matched the bearing size of the ford input shaft. I am not sure which bearing difference they are referring to. In my view, there would be a couple of critical points. 1) The main input bearing is a pressed on roller unit that must match the input shaft diameter and also fit the T-18 case. The bearing retainer fits around this and bolts to the case. There is a large snap ring (about 3" diameter)which fits around the outside of the bearing cage and this fits against the case to set the depth of the input shaft. 2) The input shaft is bored to accept large needle bearings which forms the bearing surface for the mainshaft. The mainshaft fits into the input shaft with the needle bearings upon assembly.
To my knowledge, the T-18 mainshaft input diameters are the same for all configurations. The differences are in the tailshaft configurations. Of course, we want the short tailshaft which is configured for our Jeep rear bearing retainer with the Dana 20 Tcase pattern. In my case, both Jeep T-18 's already had this shaft. My Ford donor T-18 had a longer shaft, which I did not use.
The gear configurations are fixed. For instance, the 4:1 and 6.32:1 1st gears units are identical for both configurations. This may seem odd at first glance. The gearing difference is in the input shaft and countergear ratio. The 6.32 ratio countershaft has a much larger gear which is located at the front of the case. This makes the 6.32 input gear a smaller diameter to match this. Remember, the shaft centers remain the same. In other words, the center of the countershaft and the mainshaft are fixed by the case design.
The end result to all of this information is that it works! If you can find a donor Ford T-18 for a decent price, I would suggest that you tear them down amd match up the parts. I think you will find that you can convert your T-18 to a 6.32 ratio successfully.
I reviewed your earlier post with the photos again. My bellhousing bolts directly to the T-18 . However, the small adapter shown in your photo will probably work fine if the bellhousing fits your motor. It does not appear to have the really long FSJ input shaft.
Are you certain this T-18 is a close ratio or 4:1 version? If it is a 1979, then I thought these were all the 6.32 version. It is ready to go as is! Put in 1st gear, mark the shaft with chalk, spin and count the input revolutions to get one turn at the output.
I thought the 4:1 ratio Jeep T-18 's were all early units 1972 - 1975 plus some 1976 units.
your input has opened up a whole new relm of possibilities with the T-18 and I do appriceate your contribution.
As to the particulars of my configuration, the part number on the case may be indicating a wide ratio 1979 model but I am at this moment 90% sure that it is a close ratio and the adapter may prove this out.
Right now the only thing I am reasonably sure of is that it is one of the 16+ variations that novak refers to for the Jeep T-18 .
I need to measure the input shaft on the Jeep T-18 that I own to see if the ford will be long enough if I am required to use the adaptor plate to connect to the bell housing.
The T-18 project is schedualed for this winter so this is still part of the voyage of discovery.
your input has opened up a whole new relm of possibilities with the T-18 and I do appriceate your contribution.
As to the particulars of my configuration, the part number on the case may be indicating a wide ratio 1979 model but I am at this moment 90% sure that it is a close ratio and the adapter may prove this out.
Right now the only thing I am reasonably sure of is that it is one of the 16+ variations that novak refers to for the Jeep T-18 .
I need to measure the input shaft on the Jeep T-18 that I own to see if the ford will be long enough if I am required to use the adaptor plate to connect to the bell housing.
The T-18 project is schedualed for this winter so this is still part of the voyage of discovery.
Well I guess I am assuming now you do have a Close ratio ( 4.02 low) Jeep T-18 that you wish to convert to the 6:32 low gear? As Johnbilt has mentioned to get to the 6:32 Low gear the Input & Counter shaft has to be changed.........and that's where it gets sticky between the Jeep & Ford versions although both built by Borg Warner and some parts do interchange.
