StraightSix Posted September 30, 2021 Author Share Posted September 30, 2021 I don't know what Ford shop manual you have, but have you looked at the excerpt we have on site: Documentation/Driveline/Transmissions/Manual Transmissions/NP435? It has the page below on measuring, showing both in the case as well as on the bench methods. And later it says "When the input shaft end play has been established, re-check the synchronizer clearance. It should be 1.77-2.41mm (0.070-0.095 inch). Adjust, if required." Gary, Thanks for doing some digging! My manual is the "David Graham edition" of the 1984 shop manual. It has the same verbiage and illustrations as the one here on the site but is clearly a different edition based on the formatting. I suppose my issue is that the length represented by the brackets around "synchronizer assembly" in the top picture in figure 9 is variable depending on your treatment of the synchro assembly. Im not sure if I need to press the synchro assembly together until everything "bottoms out" or if I need to align the edges of the cups with the inside faces of the synchros themselves (as I have seen someone do before), or perhaps something other than those options. unfortunately, that difference generates a fair deal of change when we are talking about thousandths or even ten-thousandths. Thanks for taking some time to investigate! Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 30, 2021 Share Posted September 30, 2021 Gary, Thanks for doing some digging! My manual is the "David Graham edition" of the 1984 shop manual. It has the same verbiage and illustrations as the one here on the site but is clearly a different edition based on the formatting. I suppose my issue is that the length represented by the brackets around "synchronizer assembly" in the top picture in figure 9 is variable depending on your treatment of the synchro assembly. Im not sure if I need to press the synchro assembly together until everything "bottoms out" or if I need to align the edges of the cups with the inside faces of the synchros themselves (as I have seen someone do before), or perhaps something other than those options. unfortunately, that difference generates a fair deal of change when we are talking about thousandths or even ten-thousandths. Thanks for taking some time to investigate! I've not rebuilt that transmission, so all I can tell you is what I read. Sorry. But I would think that everything is supposed to fit together and "bottoms out", but that is just my thinking. And then you "MAINTAIN DOWNWARD PRESSURE ON INPUT SHAFT WHILE USING FEELER GAUGE". Just my guess. As for investigating, it caused me to realize I'd used an old way of presenting that section on the website. So I took the time to update it and now it is much cleaner and clearer. Plus, I OCR'd the file so you can search it for terms. So it was all for good. Link to comment Share on other sites More sharing options...
StraightSix Posted October 1, 2021 Author Share Posted October 1, 2021 I've not rebuilt that transmission, so all I can tell you is what I read. Sorry. But I would think that everything is supposed to fit together and "bottoms out", but that is just my thinking. And then you "MAINTAIN DOWNWARD PRESSURE ON INPUT SHAFT WHILE USING FEELER GAUGE". Just my guess. As for investigating, it caused me to realize I'd used an old way of presenting that section on the website. So I took the time to update it and now it is much cleaner and clearer. Plus, I OCR'd the file so you can search it for terms. So it was all for good. Ok Guys - I just got off the phone with a very Helpful transmission expert at Novak. His advice for synchro shims is as follows - -measure for clearance between the rear face if 4rth gear and the front face of the 4rth gear synchro cup. this measurement is similar/equivalent to measuring between 3rd gear and the rear face of the rearmost synchro shim but is much easier to do. -prepping/dressing the synchro cups to the synchros before measuring - the synchro cups need to be gently pressed onto the synchro mechanism until they start to generate light drag. this of course, is subjective in nature. once they begin to generate slight drag they are at the correct depth, but you also need to check that they are aren't crooked on the synchro rings. in other words, they don't need to be pushed farther/deeper on to the synchro ring on one side of the cup than the other. everything needs to be straight. - I was advised that the gap between the front face of the 4rth gear synchro cup and the rear face of the 4rth gear should ideally be .040"-.050". this is slightly tighter than any OE manual spec Ive seen, however the dodge manual my friend has states something to the tune of .050"-.070". Im a little afraid of eating synchros by setting it all too tight, so Ill be aiming for as close to .050" as I can get, without being tighter than .050". hopefully this can help someone down the road. Link to comment Share on other sites More sharing options...
StraightSix Posted October 7, 2021 Author Share Posted October 7, 2021 Ok Guys - I just got off the phone with a very Helpful transmission expert at Novak. His advice for synchro shims is as follows - -measure for clearance between the rear face if 4rth gear and the front face of the 4rth gear synchro cup. this measurement is similar/equivalent to measuring between 3rd gear and the rear face of the rearmost synchro shim but is much easier to do. -prepping/dressing the synchro cups to the synchros before measuring - the synchro cups need to be gently pressed onto the synchro mechanism until they start to generate light drag. this of course, is subjective in nature. once they begin to generate slight drag they are at the correct depth, but you also need to check that they are aren't crooked on the synchro rings. in other words, they don't need to be pushed farther/deeper on to the synchro ring on one side of the cup than the other. everything needs to be straight. - I was advised that the gap between the front face of the 4rth gear synchro cup and the rear face of the 4rth gear should ideally be .040"-.050". this is slightly tighter than any OE manual spec Ive seen, however the dodge manual my friend has states something to the tune of .050"-.070". Im a little afraid of eating synchros by setting it all too tight, so Ill be aiming for as close to .050" as I can get, without being tighter than .050". hopefully this can help someone down the road. Hi Guys! the transmission is done. In the end, it came down to needing either two or three shims for my synchos. My friend and I spent about 1/2 an hour trying to measure the gap and by the end of it we were only sure of two things. the first, this is a really subjective measurement and we couldn't agree on a number, the second, it was on the looser end of things with 2 shims and more "in the middle" with 3 shims. we decided to put it together both ways and conduct a shifting test to decide. 1st, 2nd, an R are pretty much guaranteed.. I dont know what you would have to do wrong to make those not work. 3rd and fourth on the other hand can be surprisingly finicky. In any case, the test procedure was to place the shifter in N, attempt to enter 3rd, put the shifter back in neutral, then rotate the input and output shafts to unlock the bound synchros. we repeated this 10 times each. Our cumulative success rate for 3rd between the two of us was 75%, and 95% for 4rth while using 3 shims. this was much better than 2 shims, so we put it together with 3. Im banking on the fact that the input and output shafts will be spinning to help with shifting into 3rd, as well as synchro break in and being truly soaked in an oil bath instead of just wetted down. I would like for it to be practically 100% like 4rth, but we only have .015" shims, and I dont even think other options are available meaning that adjustments are somewhat coarse. I think it will be fine. It was a huge asset to have a friend over who knows the shifting characteristics of the transmission. The tranny is on the garage floor under the bronco and the transfer case is on the work bench for cleanup and tear down. No news from the engine shop. Ill keep you guys posted! Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 7, 2021 Share Posted October 7, 2021 Hi Guys! the transmission is done. In the end, it came down to needing either two or three shims for my synchos. My friend and I spent about 1/2 an hour trying to measure the gap and by the end of it we were only sure of two things. the first, this is a really subjective measurement and we couldn't agree on a number, the second, it was on the looser end of things with 2 shims and more "in the middle" with 3 shims. we decided to put it together both ways and conduct a shifting test to decide. 1st, 2nd, an R are pretty much guaranteed.. I dont know what you would have to do wrong to make those not work. 3rd and fourth on the other hand can be surprisingly finicky. In any case, the test procedure was to place the shifter in N, attempt to enter 3rd, put the shifter back in neutral, then rotate the input and output shafts to unlock the bound synchros. we repeated this 10 times each. Our cumulative success rate for 3rd between the two of us was 75%, and 95% for 4rth while using 3 shims. this was much better than 2 shims, so we put it together with 3. Im banking on the fact that the input and output shafts will be spinning to help with shifting into 3rd, as well as synchro break in and being truly soaked in an oil bath instead of just wetted down. I would like for it to be practically 100% like 4rth, but we only have .015" shims, and I dont even think other options are available meaning that adjustments are somewhat coarse. I think it will be fine. It was a huge asset to have a friend over who knows the shifting characteristics of the transmission. The tranny is on the garage floor under the bronco and the transfer case is on the work bench for cleanup and tear down. No news from the engine shop. Ill keep you guys posted! I suspect you've done a more thorough job than most people do on them, and I'll bet it shifts nicely. Link to comment Share on other sites More sharing options...
StraightSix Posted October 8, 2021 Author Share Posted October 8, 2021 I suspect you've done a more thorough job than most people do on them, and I'll bet it shifts nicely. Thanks Gary. As Ive said atleast once before, your calm cool confidence helps more than you may know. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 8, 2021 Share Posted October 8, 2021 Thanks Gary. As Ive said atleast once before, your calm cool confidence helps more than you may know. Happy to help. Link to comment Share on other sites More sharing options...
StraightSix Posted November 5, 2021 Author Share Posted November 5, 2021 Happy to help. Hey guys! I just finished up the np208. Overall Id say it was easier than the transmission and the transmission was easier than the rear axle. There were no real surprises, read the shop manual and you will pretty much see it all. Pulling the old bearings out was easily the hardest part. Take really good detailed disassembly photos, youll be glad for it later. The engine is going pretty slow :( Im going to swing by the shop tomorrow to check it out, hopefully there will finally be some progress. Im starting to get the "bronco blues" about how long its been out of comission but Im keeping that tempered with plenty of work to do. Next Ill focus on cutting out me new brackets and gage panels. If I have enough spare time I may rebuild my front hubs. I hope everyone is doing great, staying safe, and enjoying the fall. -John Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2021 Share Posted November 5, 2021 Hey guys! I just finished up the np208. Overall Id say it was easier than the transmission and the transmission was easier than the rear axle. There were no real surprises, read the shop manual and you will pretty much see it all. Pulling the old bearings out was easily the hardest part. Take really good detailed disassembly photos, youll be glad for it later. The engine is going pretty slow :( Im going to swing by the shop tomorrow to check it out, hopefully there will finally be some progress. Im starting to get the "bronco blues" about how long its been out of comission but Im keeping that tempered with plenty of work to do. Next Ill focus on cutting out me new brackets and gage panels. If I have enough spare time I may rebuild my front hubs. I hope everyone is doing great, staying safe, and enjoying the fall. -John John - Glad the t-case went so well. Mine turned out good, but I was nervous as I'd not done one before. But, they are fairly simple, so... New gauge panels? Are you doing custom gauges? Link to comment Share on other sites More sharing options...
StraightSix Posted November 5, 2021 Author Share Posted November 5, 2021 John - Glad the t-case went so well. Mine turned out good, but I was nervous as I'd not done one before. But, they are fairly simple, so... New gauge panels? Are you doing custom gauges? Just the AFR and mechanical oil pressure Gauge! Link to comment Share on other sites More sharing options...
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