| Author | Message | ||
| Chris Peters (Chris_85_rts)
Registered Member Username: Chris_85_rts Post Number: 3 Registered: 11-2006 Posted From: 66.194.150.45 Rating: N/A |
Ok, so I have a V731 in my 85 RTS. I'm pretty sure this same transmission was used in other busses, so I am hoping someone else has some experience with this issue. I am told that a common problem with slight engine heating at cruise can be that 2nd gear in the 730/731 will "drag" while the trans is in 3rd gear. I am told that the "fix" is to add a bypass between a "test port" and the bellhousing. I am told if the line is too big it will not allow the trans to shift correctly. I am told that you can check for the presense of the problem by connecting a pressure gauge to the "test port". While that might be enough info for an experienced V730 transmission tech, it is not nearly enough for me, so I was hoping someone might be able to fill in the blanks. Specifically: 1) Which is the correct "test port" and where exactly is it located? 2) Assuming I connect a pressure gauge to this port, what should it read under what driving conditions and what readings indicate a 2nd gear drag problem? 3) Assuming my test above indicates I do have this problem, and that the bypass is then needed, what size fittings and line do I use between the test port and where? Any place on the bellhousing? If you have done this please let me know. I have tried to contact two people via email who have experience with this problem, Ted Campbell at Coach Maintenace and Loren at gmbus. Still waiting a reply, so I thought I'd check here also. Thanks, Chris | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1184 Registered: 12-2000 Posted From: 71.195.127.101 Rating: N/A |
Chris - Your profile doesn't list where you're located, so guiding you to someone specifically in your area for help is difficult. However, if you have a transit system nearby, one that's been operating for 20+ years with full-sized buses, go visit the maintenance department, and ask the shop foreman to talk to his "transmission guy". Chances are very, very good that he'll have LOTS of V-730/731 experience, since this transmission was used extensively in transit operations for more than a decade. FWIW & HTH. . .  | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 66 Registered: 3-2006 Posted From: 209.50.73.48 Rating: N/A |
Chris I run a full set of gauges on the dash for my engine and transmission. 6V92TA DDEC IV /V731 ATEC. If you need a diagram of the gauge ports email me direct and I will send it to you. I can take a picture of the book page and send it as an attachment to you. Bill | ||
| James Stacy (Jimstacy)
Registered Member Username: Jimstacy Post Number: 29 Registered: 1-2001 Posted From: 68.89.22.181 Rating: N/A |
Another cause of heating can be the slipping of third gear clutch while cruising. You will not feel it or see the tach rise but the heat is there. "Da Book" has a procedure for checking that clutch while parked, (Block the wheels and be very careful) | ||
| Chris Peters (Chris_85_rts)
Registered Member Username: Chris_85_rts Post Number: 4 Registered: 11-2006 Posted From: 66.194.150.45 Rating: N/A |
I finally got the official word on this bypass. Have not tried it yet. I'll also have to check the book for third gear slip. Thanks everyone. |