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I'm in the process of rebuilding my Borg Warner T18 transmission from a '65 F100. I've opted to replace every gear which had straight cut gears as they all showed signs of wear and tooth damage: the 2nd Speed Synchronizer (AKA 1st-Reverse Slider), Reverse Idler Gear, and the Countershaft Cluster Gear. This was a non-running truck when I got it so I didn't have an opportunity to try the tranny out beforehand. I also replaced the Input Shaft due to corrosion pitting at the oil seal surface that I was unable to polish out. I purchased a rebuild kit which included bearings, gaskets, seals, brass rings, snap rings and such. I noted that the brass rings (referred to as Blocking Rings in the OHM) that were in the tranny appeared to be in very good condition with edges sharp and intact.
My findings:
Apparently, the Blocking Rings were modified in later versions of this tranny. The ones supplied in my rebuild kit have a larger tapered ID than the originals as shown in one of the photos below. The new Input Shaft has a thicker conical section which accommodates the newer Blocking Rings from my rebuild kit. The Input Shaft has a reduced cross section just aft of the splines whereas the original Input Shaft has a uniform cross section up to the sealing surface. I'm assuming the reduced section was done to facilitate tooling used to press the Input Bearing onto the case as opposed to schlepping the heavy assembly onto a hydraulic shop press; a task I am dreading due to the weight of the tranny and my aging back.
My 3rd Speed Gear has the smaller conical section that will not accept the brass Blocking Ring from my rebuild kit. I am forced to reuse my original brass piece.
The original spacers are slightly thicker (about 0.003-0.004in) than the ones supplied with the rebuild kit. The new rollers have slightly rounded ends whereas the old ones are flat. I'm inclined to reuse my spacers as they have no discernible wear steps and install the new rollers.
The hardest part by far so far, is removing the snap rings.
Original Input Shaft (left) New Input Shaft (right) New shaft L, Old shaft R the difference in conical section is more apparent from this angle New brass Blocking Ring L, original Blocking Ring R Mismatch between new-style Blocking Ring and 3rd Speed Gear Proper fit with original brass Blocking Ring Corrosion pitting on my scrapped Input Shaft. 17 years in the aviation overhaul business has made me super picky and sadly, added to my expenses.
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My quandary:
I've already spent too much on the tranny already but I'd like to replace my 3rd Speed Gear for one with the larger conical section to match the brass Blocking Ring. What I'm finding online are ones that are described having the smaller conical section. I guess I'll just have to get on the phone with vendors for clarification.
I'm guessing that there is a reason for the revised conical section on the Input Shaft and 3rd Speed Gear and it's probably not due to material cost. I suspect it has to due with a slight increase in contact area between the brass ring and steel conical section. All other aspects of these parts are unchanged.
Well, thats a shame the dirty no good scoundrels changed the parts on you! On the blocker ring, if you have to reuse the old one, its not only the pointy teeth that are important, but also the surface inside the cone. It should have small ribs, like threads, these hold oil. If they wear too far the blocker ring can bottom out against the gear without doing any "braking" effect, and also show as too much clearance between the syncro hub and gear.
Maybe a NOS one from ebay? or, try Fred, at South side Obsolete. He is all NOS, but mainly earlier flathead stuff, but you never know what he may have.
I had another look at the brass Blocking Rings. I confirmed that the inner serrations on the old ones are intact and appear exactly as the new ones. I suspect that this transmission received a rebuild kit at some point shortly before the truck was likely mothballed as the brass rings are in great shape. I did notice that the new style rings have machined recesses on the ID presumably to increase oil flow to that area. I hadn't really payed too much attention to that surface until it was mentioned above. This is more reason for me to update my 3rd Speed Gear.
Another observation I'd like to share; normally I dislike the idea of swapping out good 'ol American parts for the aftermarket stuff mostly available today. This includes the transmission gears I've replaced. I purchased these gears from one vendor so far and they all are made in India. The gears I've mentioned above are all visually well made with smooth machined finishes, much better appearance than the OEM gears I'm removing. Of course, I don't know whether or not the original gears have teeth that are case hardened or nitrided or such and I can't tell whether the replacements duplicated the original heat treatment as well. But I thought I should give a shout out and the fact that we can still get parts for an obsolete truck. I'm guessing that all the vendors likely source their parts from a limited number of parts suppliers. New brass Blocking Ring on the right ID of new ring showing recess within the ID original ring without machined recesses on ID Casting identification. I'm assuming the dash-1 (-1) signifies 1st iteration of the transmission.
I figured I'd update my findings so far as I'm finding some peculiarities in this rebuild. First off, I wasted a lot of time trying to install a forward snap ring on the 3rd Speed Gear that I replaced in order to use the newer Blocking Rings (AKA brass synchos) that came with my rebuild kit. I settled for one I found on eBay that I was assured came from an original T18 having OEM gears intact. I will show the differences between the two versions then describe my frustration I encountered while trying to reassemble the Main Shaft gears.
Original 3rd speed gear (L), replacement later style gear (R). Note slight deformation on tooth crown on replacement gear Inner bore of original gear showing no recess grooves to enhance oil flow. Additionally, note the shiny surface on the inner land suggesting significant contact as compared with replacement gear. Note the four grooves on the inner bore presumably for enhanced oil flow. Additionally, note the comparatively lighter contact witness marking on the inner land as opposed to the original gear shown above.
I've been using the 1966 edition of the Shop Manual with its exploded view diagram to reassemble this transmission. I have also watched as many youtube videos as I can for clarification but no one has mentioned the paradox I find myself in at the moment.
Focusing on the Output Shaft, we can for illustration purposes divide it into the rearward section which contains the 2nd Speed gears and related bits and the forward side containing the 3rd Speed gears and related bits. The two sides are separated by what's referred to as a Thrust Washer which is constrained in place by a Snap Ring on the forward side of it and the 2nd Speed Gear followed by a Snap Ring on the rear side of it. The 2nd Speed Gear can only rotate and does not slide; constrained by the Snap Rings. I am describing this in detail to help explain my current dilemma.
When I install the 3rd Speed Gear, looking at the exploded parts diagram there is apparently a Snap Ring installed directly forward of the gear, presumably to constrain it from moving laterally along the shaft. What I've encountered is that the "so-called" Snap Ring groove does not provide enough clearance to be installed. I've measured the distance from the aft edge of the 3rd Gear to the landing as mentioned in the photos above and found them to be within a thou or so of each other between the original gear and my replacement gear so I can't ascribe this discrepancy to the change in gears. So, my solution at the time and with a fair amount of effort I attempted to adjust both the Snap Ring thickness and distance between the landing and aft surface by lapping both pieces.as shown below.
Subject area of the Output Shaft showing what appears to be the location of a Snap Ring on the left hand side. However, if you look closely at the splines you might notice that the leading edge of the splines rearward of the groove appear slightly tapered. A feature that helped guide me to my ultimate conclusion about this groove. Original 3rd Speed Gear (L), note slight raised portion at the ID, about 0.035in which is absent on replacement gear on right. Photo showing aft surface after lapping in effort to decrease gear length in order to fit Snap Ring. Snap Ring held in place by magnet as I tried to reduce thickness and create flat surface on both edges from a stamped ring.
So, after a fair bit of lapping on a granite surface plate using silicon carbide sheets I was able to thin the Snap Ring and slightly reduce the gear length sufficiently to install the 3rd Speed Gear. Success! Or so I thought. The next component to be installed is the 3rd and High Synchronizer Hub (3 sync hub) which utilizes a Snap Ring at its forward end. Well, guess what?!!! The location of the Snap Ring groove was off-location by an amount which corresponded to the thickness of the Snap Ring I installed for the 3rd Speed Gear! WTF???
It was then that I realized that the 3 sync hub and the 3rd Speed Gear were BOTH constrained laterally by the aforementioned Snap Ring forward of the 3synch hub and Thrust Washer mentioned earlier. Removing the Snap Ring I worked so hard to install provided the necessary clearance to install the forward Snap Ring and the assembly still performed as necessary. I can see no reason to install that Snap Ring in front of the 3rd Speed Gear and now I am convinced that it is actually an oil channel instead.
Why did I go to all this trouble to document this? Well I'm hoping that others can be spared the frustration I went through and if there is any experienced persons out there who can provided any additional insight.
That's all for now as I'm off to adjust my new replacement 2nd Speed Synchronizer which does not slide effortlessly along the 2nd Speed Synchronizer Hub like my original one does.
The somewhat larger looking snap ring that they have in the first drawing is part of the 3rd/High synchronizer hub assembly. They are shown as being inboard of the two blocking rings in the forward section. The thin sort of yellowish snap ring seen in the picture below - there is one on each side.
In the MPC which uses the same drawing those are 7109 - one on either side of the hub. The first thing you'll remove as you disassemble that assembly.
Thank you so much for this clarification. Having the MPC illustration to compliment the Parts diagram really helps. I am embarrassed to admit that I completely overlooked or failed to recognized that those two thin snap rings, had I recognized them at the time, would have resolved "my missing snap ring fiasco". I spent more time than I care to admit trying to resolve this, but, at least I came to the right conclusion in the end. I appreciate the effort you took to clarify this for me.
Now for my NEXT issue with this gearbox:
I replaced the 2nd Speed Synchronizer because the straight cut gear teeth were chipped. At the time, last summer, every vendor I checked was out of stock on this part. It was mid-September when one of the vendors reached out to let me know it was back in stock. I purchased the Reverse Idler Gear as well, due to chipped teeth. These gears were purchased from this site: https://www.transmissionpartsdistrib.../t18-t19-ford/
The gears are from a source TPD PRO-LINE, they are made in India. In a previous post I commented that these gears appeared to be of comparable appearance and in some cases had smoother machined surfaces. Let me clarify/revise that statement. Appearance is one thing, fitment and functionality is even more critical.
My latest dilemma: My replacement 2nd Speed Synchronizer is supposed to slid freely on the 2nd Speed Synchronizer Hub as my original one did. With the Output Shaft held vertically in a bench vise I can slide the replacement 2nd Speed Synchronizer only up to a point where it binds with about 1/4 inch from the end. There is sufficient clearance between the splines of the two components but at a certain point the clearance goes away. I compared the clearances witnessed as I slowly slid the two Synchronizers down the Hub and observed that the OEM Hub showed a consistent clearance while travelling down the Hub. My conclusion is that the splines on the replacement Synchronizer slightly taper outwards toward the aft end. I have tried Dykem and hand stones to try to dress the splines but only getting a minor improvement after more than an hour of rework effort. I plan to contact the vendor to see if we can resolve this. I was thinking I may have to replace the 2nd Speed Synchronizer Hub as well and send them back my replacement Synchronizer so they can ensure a proper fit. This is becoming an expensive rebuild....
Re-reading your prior posts in this thread I suspect you may also be running into another thing that Ford did. In 1965 they renamed the T98A to be the T18 and changed a couple of internal things - very minor details that can go either way with a rebuild as long as you match parts. That was for 1965, 1966 and 1967. Then in 1968 Ford changed the T18 a bit more substantially. They still called it the T18, but it no longer shared many of the same parts with the T98A. I have a hunch some of the parts you have gathered are for the old style T18 and some are for the newer style T18. For the most part they interchange as long as you change everything involved within that section but it's a pain point they caused years ago, of course. Like the different input shaft and 3rd speed gear required the different sized blocking rings.
The rest of what you are saying seems like it is on point with what many have found over the years - in that USA made NOS parts are generally superior.
Incidentally, that frontmost snap ring with base part number 7064 at the far left of the MPC drawing with numbers - that dude comes in 4 different thicknesses. That's why the Ford small parts kit for this transmission has so many of that one size.
This kit is a great affordable way to get many of the snap rings, thrust washers, spacers and the retainer plate. Not correct for the 1968 and newer models.
I'd just like to say thank you for taking the time to document all this. It's extremely valuable information, and incredibly interesting to those of us who geek out on this stuff.
Well, I thought I should update this thread with what I've learned while dealing with the T18. My rebuild was put on hold when I could not match the replacement 2nd Speed Synchronizer (1st-reverse Slider) onto the 2nd Speed Synchronizer Hub. Transmission Parts Distributors gave me all kinds of excuses as to why my Hub was the problem and not their aftermarket gear. I went so far as to sending my Hub to them so that they could see for themselves only to have them claim my hub was rusty (it wasn't). Anyhow, after several unanswered emails I started to call them daily and leave messages, eventually they returned my hub and refunded my money. Needless to say I won't be doing business when them anytime soon.
I decided to purchase the 2nd Speed Synchronizer Hub and 1st-reverse Slider as an assembly from Novak Conversions after talking with one of their techs who confirmed that they too had fitment issues at one time with replacement Sliders. More money spent on this transmission, sigh!! Although, on the bright side it came with the ***** and springs with shifting plates already installed.
I assembled the transmission from what I thought at the time was correct and tried to press the bearings onto the shafts and case. Something wasn't right so I brought the transmission back to the workbench and reviewed youtube videos and photos I could find on the internet to discover that I had incorrectly placed the rearmost circlip on the Output Shaft. What I failed to appreciate is that the 3 shifting plates on the 2nd Speed Hub Assy need to line up with the 3 detents on the corresponding Blocking Ring. It was not obvious, and/or overlooked by me at the time. Failing to align these properly results in blocking the recess for the circlip which keeps the 2nd Speed Gear and 2nd Speed Hub from sliding on the Output Shaft. At the time, I thought the recess was just another oil passage.
I confirmed with Novak that if the synchros (Blocking Rings) are updated to the later style it is ALSO necessary to update the 3rd and High Synchronizer Hub with Sleeve and new thinner inserts.
At this point it is easier to list the parts that I have NOT replaced: 2nd Speed Gear and Output Shaft.
Align the Shifting Plates with the recess to set the 2nd Speed Hub Assy so that the circlip can be installed in the proper location. Proper location of circlip I did not mention this in the text, but I inadvertently moved the slider to the extent that the ***** and springs exited the Assy at a high rate of speed in 3 different directions. I was able to find 1 set,, but fortunately my used pieces were okay to reuse. The photo shows how I reassembled the springs and ***** into the hub while keeping it in a cardboard box to contain any errant escape of bits. This is important. Wear safety glasses just in case, too.
The trick to installing the springs and plate is to do it within a cardboard box. Remove the retaining spring shown atop the hub in the photo above so that the Plates can be slid in place one at a time while pressing the ball and spring with a suitable punch. Slide the 1st-Reverse Slider over the ball to constrain it while sliding the plate rearward to keep it in place. You should then be able to slide the 1st-reverse slider to install another spring and ball and use a punch to press it as before. Repeat for all three *****. Once installed and constrained by the 1st-reverse slider you can push the Shifting Plates forward to allow the retaining spring to be installed in the groove. I was able to accomplish this within 10 minutes or so and no foul words were used during this task.
Photo shows the 3rd and High Synchronizer Hub I purchased with the difference in width of the Inserts between the old version (wider) and the updated version, installed in the hub.
This has been quite an education for me and if these posts can clarify some of the differences between early boxes and later boxes and what is needing when updating a box then I will consider it a win. At the very least, I think I know these boxes pretty well at this point.
