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20 Posts
So, I just pulled my transmission thinking I had bearing issues, but there are no signs of bearing problems that I can see.
The history is, I've had the truck twelve years now, always took good care of it (wait, everybody says that...). I've upgraded the HPOP and injectors, chipped it, done a full exhaust upgrade (including bellowed up-pipes), gone through most wear items (a few failures, but more preventive maintenance). I'm at 235,000 miles, give or take, mostly highway. About six years ago, I decided to upgrade the clutch and go thorough the transmission. It came with a DMFW setup that was easy to slip with the upgrades, although nothing else particularly wrong with it. The transmission tended to grind on downshifts sometimes (particularly 5-4 and 3-2, as I recall), but that was probably partly due to a worn pivot bushing; I know I replaced it once, but it took a few years before I got wise and did the heim joint mod.
Anyway, I wonder if I should have ever gone into the transmission in the first place, since there was nothing terribly wrong with it. The syncros probably had some wear; the reverse collar and gear showed the most wear, and it's sometimes finicky to get into reverse. What was definitely a mistake was a Valair stage one clutch. It was heavy as can be, would chatter instantly unless you engaged it just right, and then the included throwout bearing blew up a couple years ago. I replaced it with a Valeo setup that's far smoother and lighter, and actually holds pretty well.
That brings me up to the reason I torn into it again. Recently it started getting noisy - seemed to be in all gears, definitely worse in lower gears and the more you revved it, but I could hear it even going down the highway in fifth. It was a grinding sort of noise: a lot like gear rollover noise. It wasn't constant relative to RPM or throttle, it'd kind of come and go depending on how high it was revving and how hard you were pushing. The only big issue in terms of shifting is that forth gear is hard to engage without grinding - especially down-shifting. I checked the fluids and drained the transmission. I found some flecks of metal, and the fluid looks brown and pretty opaque. It also has a slight metalic sparkle to it in the light. No metal shavings or bigger pieces though. I started off with regular ATF after the earlier transmission work, then changed that out to Red Line MTL after a few thousand miles - I figured it'd perform better, and that it'd be a good idea to use the initial fill to flush out anything lingering from having it open. It had plenty of fluid; I'd over-serviced it to lesson the gear rollover noise, and it started pouring out the fill when opened it, so it never ran low. The fluid in the transfer case looked brand new. The oil in the differential might have been a shade darker than new oil, but I'd be embarrassed to throw it out if I were changing it (I've changed it a couple times over the years - Mobil synthetic).
The one thing definitely wrong is a leaking output shaft seal. I think that ended up either a little crooked or driven in too deep. There was a half cup or so of oil between the transmission and transfer case. I already have a new bearing set, from Midwest Trans (where I got the kit the first time too). One thing I noticed is that all the bearings are Koyo, about as good as you can get, except the input shaft bearing. It had no marking other than the bearing number and "China." I think the first kit I got was the same way; I pulled the pocket bearing (easy) and input shaft bearing (less easy) already, and the input bearing that was in it also appears to have been generic. So, the two possibilities I see in the transmission are that I got the bearing preload wrong, or one of those bearings is wearing in a way that's not obvious, but causing problems. I did check the preload on both shafts the last time, and my calculation was that the shims that were in it put it in the correct range.
I'm debating whether to touch the countershaft bearings, but I'm going to go ahead and do all the main shaft bearings. I bought a National bearing and race for the input shaft to eliminate that possibility. I wish I could get my hands on a shim kit; my thought now is that if it's near the looser end of tolerance, I'd shim it to the tighter, but that's kind of hard to do if I can't find shims. Hopefully tomorrow I can get the rest of the bearings done and see what I have and what I might need, then call around and see if anyone in Billings might have some, or be able to make one.
Anyway, long story, but I'd appreciate any ideas. I half-wonder if I jumped the gun, but it's definitely making noise where it wasn't before, and it seems to be coming straight from the transmission.
The history is, I've had the truck twelve years now, always took good care of it (wait, everybody says that...). I've upgraded the HPOP and injectors, chipped it, done a full exhaust upgrade (including bellowed up-pipes), gone through most wear items (a few failures, but more preventive maintenance). I'm at 235,000 miles, give or take, mostly highway. About six years ago, I decided to upgrade the clutch and go thorough the transmission. It came with a DMFW setup that was easy to slip with the upgrades, although nothing else particularly wrong with it. The transmission tended to grind on downshifts sometimes (particularly 5-4 and 3-2, as I recall), but that was probably partly due to a worn pivot bushing; I know I replaced it once, but it took a few years before I got wise and did the heim joint mod.
Anyway, I wonder if I should have ever gone into the transmission in the first place, since there was nothing terribly wrong with it. The syncros probably had some wear; the reverse collar and gear showed the most wear, and it's sometimes finicky to get into reverse. What was definitely a mistake was a Valair stage one clutch. It was heavy as can be, would chatter instantly unless you engaged it just right, and then the included throwout bearing blew up a couple years ago. I replaced it with a Valeo setup that's far smoother and lighter, and actually holds pretty well.
That brings me up to the reason I torn into it again. Recently it started getting noisy - seemed to be in all gears, definitely worse in lower gears and the more you revved it, but I could hear it even going down the highway in fifth. It was a grinding sort of noise: a lot like gear rollover noise. It wasn't constant relative to RPM or throttle, it'd kind of come and go depending on how high it was revving and how hard you were pushing. The only big issue in terms of shifting is that forth gear is hard to engage without grinding - especially down-shifting. I checked the fluids and drained the transmission. I found some flecks of metal, and the fluid looks brown and pretty opaque. It also has a slight metalic sparkle to it in the light. No metal shavings or bigger pieces though. I started off with regular ATF after the earlier transmission work, then changed that out to Red Line MTL after a few thousand miles - I figured it'd perform better, and that it'd be a good idea to use the initial fill to flush out anything lingering from having it open. It had plenty of fluid; I'd over-serviced it to lesson the gear rollover noise, and it started pouring out the fill when opened it, so it never ran low. The fluid in the transfer case looked brand new. The oil in the differential might have been a shade darker than new oil, but I'd be embarrassed to throw it out if I were changing it (I've changed it a couple times over the years - Mobil synthetic).
The one thing definitely wrong is a leaking output shaft seal. I think that ended up either a little crooked or driven in too deep. There was a half cup or so of oil between the transmission and transfer case. I already have a new bearing set, from Midwest Trans (where I got the kit the first time too). One thing I noticed is that all the bearings are Koyo, about as good as you can get, except the input shaft bearing. It had no marking other than the bearing number and "China." I think the first kit I got was the same way; I pulled the pocket bearing (easy) and input shaft bearing (less easy) already, and the input bearing that was in it also appears to have been generic. So, the two possibilities I see in the transmission are that I got the bearing preload wrong, or one of those bearings is wearing in a way that's not obvious, but causing problems. I did check the preload on both shafts the last time, and my calculation was that the shims that were in it put it in the correct range.
I'm debating whether to touch the countershaft bearings, but I'm going to go ahead and do all the main shaft bearings. I bought a National bearing and race for the input shaft to eliminate that possibility. I wish I could get my hands on a shim kit; my thought now is that if it's near the looser end of tolerance, I'd shim it to the tighter, but that's kind of hard to do if I can't find shims. Hopefully tomorrow I can get the rest of the bearings done and see what I have and what I might need, then call around and see if anyone in Billings might have some, or be able to make one.
Anyway, long story, but I'd appreciate any ideas. I half-wonder if I jumped the gun, but it's definitely making noise where it wasn't before, and it seems to be coming straight from the transmission.
