| Author | Message | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 312 Registered: 11-2004 Posted From: 166.194.229.178  Rating: N/A |
Hey guys... I'm posting using my phone, so sorry about spelling and grammar! Having an interesting problem shifting this tranny... The typical double clutching isn't working. Only way I can shift up or down is to actually match engine and tranny RPMs to drop into gear.... It's not that difficult, but downshifting is proving to be a real PITA. Any ideas what's up with this thing? Am I just missing something somehow? Jack said something about the clutch lockup plate when I stopped in to his place the other day... I don't have the service manual for this tranny to troubleshoot and diagnose with. Any assistance would be appreciated. If you'd like to call me, my cell # is 318 840 9254. -Mac | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 76 Registered: 5-2007 Posted From: 70.53.182.27  Rating: N/A |
the double clutching is supposed to help match engine and tranny rpms, there are no synchros in the tranny so that is the only way it will go into gear (matched rpms). Takes time to learn. For shifting down you really need to floor it at first to get a feel for it. Also buffaloes are supposed to be the hardest of the 4spd spicers to shift due to the liinkage runs. Good Luck. p.s. WHne I used to travel by bus in Mexico, experienced drivers would still miss shifts on the buffaloes. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1008 Registered: 12-2000 Posted From: 71.3.75.244  Rating: N/A |
By "clutch lockup plate" I was referring to the clutch thingy that GM installed in some of the manual transmissions to aid shifting. Sorry I missed your call yesterday. We will be out this afternoon, but you can call this morning or this evening. Jack | ||
| J.L.Vickers (Roadrunnertex)
Registered Member Username: Roadrunnertex Post Number: 49 Registered: 10-2006 Posted From: 69.34.188.48 Rating: N/A |
I think what Jack is talking about is the countershaft brake on the Spicer transmission. See chapter 17-10 in the 4905 parts book X-171010 jlv | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 688 Registered: 8-2006 Posted From: 74.32.92.133 Rating: N/A |
The clutch brake is for stopping the transmission shaft from turning and all i have been around over the years it was for shifting into 1st gear had nothing to do with down shifting and would cause you problems shifting if you pushed the pedal to hard and deep applying the brake did on my MCI 5 try pushing the clutch about 1/2 way down good luck (Message edited by luvrbus on April 11, 2009) | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 313 Registered: 11-2004 Posted From: 166.193.44.234 Rating: N/A |
Jack... No worries guy. I really enjoyed the visit! I hope your planned trip goes well. Ya did a super job with your motor swap, I'm glad I was there for your first crank of her.... Always a sweet sound!  R.J. .... I tried what you said with trying to shift to 4th with her running to get the tranny to settle down from dead stop... No go. I try to pull it down to 4th and it VERY forcefully throws the stick back to neutral... Same with third. No free play in the clutch... But there's also a quirk with third... It doesn't so much as 'drop' into gear as much as it seems to just 'hang on' ... The other gears, there's a definite feeling to them. Third gear... I have to very forcefully hold it or it just pops back out the moment the clutch is popped, or when the engine begins to mismatch tranny speed... I can make it work, but I think something is wrong, or seriously out of adjustment. I'll have to go through da book and readjust everything when I get her back to Louisiana... I simply don't have ALL the tools I need for that with me... Greyhound limited my weight on the way down, heh... -Mac | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 77 Registered: 5-2007 Posted From: 70.53.182.27 Rating: N/A |
should be a little free play in the clutch. Worn linkages cause all sorts of bs hopefully that's ll it is. Sounds like you are making do, remember to enjoy the ride. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1393 Registered: 10-2003 Posted From: 71.58.110.9  Rating: |
If yours has the oil wet clutch, you'll need to be sure the plates aren't hanging or dragging, which will cause/require turning engine off to get into gear from neutral. Also need to check clutch travel and make sure there isn't a lot of wear in linkage causing lost motion, not letting clutch completely disengage. Oil clutch models don't require as much release lever movement to release cleanly. There is a cover on the end of the transmission case towards outside passenger side of coach. Beneath it are two or three small fibre and also a couple steel discs. When the clutch is fully depressed, these are supposed to engage and slow or stop trans shaft from turning to enable faster shift from neutral to 1st gear. This is only supposed to be used for that purpose. They are small and will not tolerate abuse. The rest of time shifting, you are not to push clutch pedal clear to floor to change gears, if everything is in good working condition. As far as not staying in gear, either the linkage is not adjusted properly, the shift linkage or shift forks in top of trans cover are excessively worn, the internal transmission main and/ or countershaft have too much endplay, or the teeth on the shift collar or transmission gear have rounded from abuse or wear and won't stay engaged. Another words, several things to check out. A "DABOOK" for your coach should be your first purchase, as it has all the info you need to diagnose and repair this. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 865 Registered: 11-2005 Posted From: 208.54.200.172 Rating: N/A |
Mac, You kind of confused me. Your first post indicated that downshifting was the problem which I, and others, interpreted to mean while moving. Your next post is about shifting into gear while stopped? These are two distinctly different problems. A clutch brake is meant to solve the stopped problem. The brake works when the clutch is pushed all the way to the floor so it is easy to go from N to any gear. As luvbus said, this can cause problems if you push it all the way in while moving - only use it while stopped. The question now is - do you have a clutch brake? If you do the brake discs are probably worn out. There is a way to renew these without removing the trans, the much preferred way!! This is done by cutting a small section from the discs and slipping them over the shaft. I have a diagram somewhere showing how to do that if you need it. If it is a Spicer clutch you may have a brake. On the other hand, you probably don't have a clutch brake since I don't think they were often used on buses. I may be wrong about this. I've only seen them on truck trans of 9 - 15 SP. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1394 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
You don't remove trans to remove those discs; you unbolt that round cast alum cover on end of trans. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 867 Registered: 11-2005 Posted From: 208.54.200.172  Rating: N/A |
John, You're right, I was thinking of the drive shaft, not the whole trans. I did one on my ole Dodge C900 a long time ago but don't remember exactly how I did it. (Message edited by gusc on April 11, 2009) | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 314 Registered: 11-2004 Posted From: 32.161.24.104 Rating: N/A |
Sorry, both issues are being experienced... Shifting from gear to gear while under way, and shifting into any gear from dead stop... The additional info arose from a convo with RJ. I'll be able to try out the tips while under way when I get moving on the road again on Monday... RJ thinks my problems are likely a result of poorly adjusted linkages... I'll be able to readjust everything to spec once I'm back home with her and be able to update with the status of whether shifting was any easier or not with the tips received from everyone... For now... Thanks! -Mac | ||
| FloridaCliff (Floridacracker)
Registered Member Username: Floridacracker Post Number: 394 Registered: 7-2004 Posted From: 75.74.166.245 Rating: |
Mac, Make sure and check the shiffting arms on top of the tranny. They are held on with some nuts with cotter pins. I was having some trouble shifting and found they were several turns loose. I adjusted them so they could move freely, but stayed upright. When they were loose the two arms would hit each other and sometimes bind going into third. Cliff 4905A-1160 | ||
| FloridaCliff (Floridacracker)
Registered Member Username: Floridacracker Post Number: 395 Registered: 7-2004 Posted From: 75.74.166.245 Rating: N/A |
Mac, One other thing. Put the tranny in neutral when checking those arms. They may look fine, but try moving them on top with your hand to see. Cliff 4905A-1160 | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 315 Registered: 11-2004 Posted From: 32.160.11.143 Rating: N/A |
LOL... Funny thing you mention that... I had lost third and fourth altogher at one point... Went back to look... No nut on that arm at all... Only thing I had to hold the damn thing together? Zip ties. I will have to find another nut when I get her home... It's holding up well, considering the forces at work back there! I think ALL of us nuts have a little 'MacGyver' in us. ;) -Mac | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1396 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Those damn zip ties won't hold anything for long....use DUCT tape. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1543 Registered: 12-2000 Posted From: 76.68.122.31  Rating: N/A |
My advice? Have a pee, get 'r in the big hole and get on down the road. All the way. This is no time for goofing off and sightseeing. The fewest shifts between there and there... How many might be left? happy coaching! buswarrior | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 868 Registered: 11-2005 Posted From: 208.54.200.1 Rating: N/A |
I had to replace most of the shift rod forks, pins and bellcrank arms for both trans and clutch linkage on my bus to get it to shift properly. Some forks and bellcrank arms were worn almost through. There are so many of these pieces that a bit of slack in each one adds up to a bunch by the time it gets to the trans. Proper clutch adjustment is also very important and something I spent a lot of time doing. Even after all this the shift levers at the trans sometimes hang up, usually in third when I try to downshift, when I get sloppy with the clutch. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1399 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Gus, if you do the tower and levers at rear of coach between engine and bulkhead..... WHAT A PITA!!!!!All that can be said is, once it's done, it'll never need done again, even if it rarely gets greased again. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 869 Registered: 11-2005 Posted From: 208.54.200.182 Rating: N/A |
John, Amen to that. I stood on my head for two days and could just barely reach some of the bolts and screws. It is nice to know that I won't ever have to do it again!! Greasing is not too bad, mine has a long tube up from the bottom with a Zerk on the bottom end. However, the grease does not flow into all the bushings so it has questionable effect. | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 331 Registered: 11-2004 Posted From: 74.193.225.134 Rating: N/A |
R.J.... This post is a little late, but I just realized I didn't get a chance to thank you for your time and for calling me to try to help me with some of my problems and questions... So, I want to take a moment to do just that. THANK YOU! Cheers! -Mac |
