| Author | Message | ||
| Debo Cox (Debo)
Registered Member Username: Debo Post Number: 4 Registered: 1-2009 Posted From: 149.168.204.10  Rating: N/A |
Hi folks, I've searched the archives for an answer to my question and I'm more confused than before, so here we go... I have a 1981 MCI MC9 with the 8V71/4-speed manual Spicer configuration. With a properly adjusted clutch depressed to the floor at a dead stop, should I not be able to go from neutral to first without grinding? Seems like a simple enough question, but I've read all kinds of stuff to the contrary on here. I'm just confused. I've been driving manual transmission cars my whole life, and even drove a 30-foot truck with a manual transmission for 2 years, so it seems to me like the clutch a little out of adjustment and not disengaging the gears. I've got my "da book" on order, but I just wanted to make sure what "properly adjusted" looks like. Thanks for the help! | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 906 Registered: 10-2006 Posted From: 76.216.70.102  Rating: N/A |
" With a properly adjusted clutch depressed to the floor at a dead stop, should I not be able to go from neutral to first without grinding?: Probably you didn't wait long enough for the mass to slow down. The usual technique is to stop , with out shifting from what ever gear you were in, then shift to First . Should be no grinding. Some coaches did have clutch brakes , but they never seemed to be a success. To use them ,ONLY by stepping all the way down would the brake actually stop the clutch disc. Problem was many drivers would step all the way down for many shifts , wearing the unit out quickly. Some time with the engine off , step on the clutch and start the engine "in gear" shift to neutral and then back to first , should be NO grinding if all is well. FF | ||
| Debo Cox (Debo)
Registered Member Username: Debo Post Number: 5 Registered: 1-2009 Posted From: 76.0.172.15 Rating: N/A |
OK, here's the resolution... After work today I performed the "start the engine in gear" test recommended by Fred above. This confirmed to me that the clutch was not releasing as much as it should because after 30 seconds or so the gears were still spinning - resulting in grinding when I tried to shift from neutral to first at a dead stop. I had previously tried to adjust the clutch as recommended with the adjustment knob but wasn't clear on the exact meaning of the direction to tighten the knob until "pressure" or "resistance" is felt. Apparently it's a little more than I was thinking it was, because when I tightened the knob a bit tighter, then backed off a turn as recommended, I was able to have the gears spin down 10-15 seconds after depressing the clutch as is normal. I'm confident this is adjusted correctly now, and I appreciate the help - from those on the board, and from those who took the time to email me personally. Thanks! | ||
| Ednj (Ednj)
Registered Member Username: Ednj Post Number: 259 Registered: 3-2003 Posted From: 173.3.44.88  Rating: N/A |
Debo, Just to be sure you have it adjusted right, a 200 mile trip North to the Delaware Rally maybe in order this weekend. lol | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 979 Registered: 11-2005 Posted From: 208.54.200.45  Rating: N/A |
I've adjusted my 4sp Spicer many times and I'm never able to put it into neutral with the engine running no matter how long I wait. The only time it is possible is when the trans oil is cold, otherwise it is impossible. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 908 Registered: 10-2006 Posted From: 76.216.70.102 Rating: N/A |
Have you tried the start in gear , shift to neutral, then back to first? With clutch depressed all the time? If it doesn't work the clutch is dragging somehow. FF | ||
| Debo Cox (Debo)
Registered Member Username: Debo Post Number: 6 Registered: 1-2009 Posted From: 149.168.204.10 Rating: N/A |
Hey guys, That's how I just knew something was wrong. I can't imagine that someone would design a transmission you can't get into first gear from neutral with the engine running. Something just HAD to be out of adjustment. Ultimately Fred's little test showed me exactly what I needed to know. My thinking was that the job of the clutch is to disengage the spinning gears. If the gears don't stop spinning, then the clutch isn't disengaging. It may take a while for the mass of the gears to slow down, but if they don't slow down in some acceptable length of time, then the clutch is engaged to some degree. Thanks again for the info guys, and Ed - I won't make it to Delaware this time. I've got a couple of tires I need to replace before I take any long trip, but thanks for the invite. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 102 Registered: 5-2007 Posted From: 174.91.220.184  Rating: N/A |
Seems to me if the pilot bearing is worn/rough it will spin the main shaft (lay shaft?) when the clutch is depressed if the tranny is in neutral. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 961 Registered: 7-2006 Posted From: 74.162.81.77  Rating: N/A |
We're not talking "wet clutches", are we? Kinda' important to know before giving a suggestion? | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 136 Registered: 11-2003 Posted From: 70.193.177.109 Rating: N/A |
Don't know if this would apply, but it seems to me that i remember as a kid, driving a few old farm trucks that when you came to a stop you had to double clutch it to get it to go into 1st without grinding. You might give that a try and see what happens. | ||
| Clint Hunter (Truthhunter)
Registered Member Username: Truthhunter Post Number: 301 Registered: 1-2009 Posted From: 24.129.232.232  Rating: N/A |
#stop bus with transmission engaged in last gear used, clutch pushed down before stalling. *keeping clutch pushed down (released) stops counter shaft from free wheeling and all that is still coupled to the output. ... this assume clutch fully releases, dogs & shift forks are not worn out, nor many other parts such as bearings, pilot bearing, gear teeth crowns. etc. etc. .. on those with a working clutch brake, pushing all the way to floor (only when at a stop) slows or stops the drag effect on the front parts of the transmission, including the clutch friction disc(s)a little sooner. De-clutching a little earlier than minimum engine rpm, does the same end effect. .The old rule of dhumb is simple, if vehicle is not parked, the transmission should be in one gear or being shifted between gears. + have you change that fluid & "catch filter" recently while doing your transmission , clutch & linkage lube/inspection ? dogs or synchro rings (if equipped) work better when they are clean , with the appropriate weight of oil. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1587 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
Gus, the pilot bearing is stiff or the clutch plate is dragging. Also make sure you don't have some lost motion from play in the clutch linkage not allowing the disc to completely disengage. Those 4104 trannies are so free after that many miles that it doesn't take much to keep the input shaft spinning. Just a little bit of drag from the disc will do it. You can have someone hold in the clutch pedal in while you check for play between disc and flywheel through the inspection hole. Check in several places. One or two fingers on the pressure plate being a little off will do it. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 981 Registered: 11-2005 Posted From: 208.54.200.84 Rating: N/A |
John, Thanks, I'll give it a try. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1588 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Forgot to add...use about a .030 to .060 feeler gage; preferably a long version. The bushings on the pivot points on the clutch release fingers or levers can wear uneven from each other and allow part of the disc to drag. They are adjustable, but the adjustment nuts are staked when re manufactured.They are also a pita to adjust. By this time, usually the pressure plate and clutch disc get replaced. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 983 Registered: 11-2005 Posted From: 208.54.200.38 Rating: N/A |
I have adjusted Spicer clutches with and without clutch brakes on big trucks but this one defies everything I do with it. I have driven 18 wheelers and none were as hard to shift, even the cabovers with their loose connections. I haven't tried the "leaving it in gear until stopped" but that doesn't solve the problem of having to hold in the clutch at lights. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 915 Registered: 10-2006 Posted From: 76.192.0.94 Rating: |
Holding the clutch at lights works fine because the throw out bearing (like most bus stuff) is really robust. FF | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1594 Registered: 10-2003 Posted From: 71.58.110.9 Rating: |
Maybe a synthetic 50 weight oil would help; it might not thin down when hot like the oem oil. Mine shifts fast when cold and gears slow down quicker. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 969 Registered: 7-2006 Posted From: 74.162.73.166 Rating: |
Re: "I haven't tried the "leaving it in gear until stopped" but that doesn't solve the problem of having to hold in the clutch at lights." Jolts of memories seem to hit me... I can't remember shifting a bus into neutral at a light, ever... We'd stop with clutch depressed, keep it depressed, and slid the gearshift from whatever gear we stopped in, directly into first. We did that quickly, without releasing the clutch. If it was a carryover from driving the wet-clutches or not, I can't say.... But even an Eagle could be a pain in the arse getting into first, at times. |
