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MG TD TF 1500 - Third gear jump
|Hello. I have an mg td, 1952. When I drive in third gear, reducing rpm, the third gear jumps. However, accelerating and climbing rpm, third gear does not jump. I have reviewed the forum and other forums and find no solution. Would greatly appreciate help to know that piece can be wrong or to be repaired.|
|Try looking around in the archives again. There are volumes in there about popping out of gear. The search function isn't the best, but give it a try. there was also a thread within the past couple months about similar problem, try to find that one too. George|
|Fora definetive answer go to allexperts.com MG car repair And ask the question of Barrie Jones he wrote the book and made the video for the XPAG gear box rebuild. He recently helped me with a first gear pop out problem.|
My bet is that you have a worn synchro. When under power there is enough friction to hold it in place, but when coasting it can slip out. Mine did the same thing until we took it to a John Twist transmission rebuild seminar and replaced the worn synchro.
Good luck and happy holidays.
Scott Ashworth - '54 TF
|S. R. Ashworth|
|This is a common problem with the TD and TF gearbox. I have had success in fixing the problem by inserting an additional washer between the center bearing and the circlip on the mainshaft. The thickness of this washer was about the same as the existing one. The effect of the washer is to move the mainshaft and the third gear forward. |
Cheers, Hugh Pite
|Click "Archive" above, enter "popping gear" in the search box, mark "all of these words" and search. Several relevant threads appear. I would also try first gear, as some of that stuff is relevant also. George|
Summarize the messages received so far:
George: “Try looking around in the archives again”
George: “Click "Archive" above, enter "popping gear" in the search box, mark "all of these words" and search”.
Cheers,Keith: “answer go to allexperts.com MG car repair And ask the question of Barrie Jones he wrote the book and made the video for the XPAG gear box rebuild”.
Hugh Pite: “inserting an additional washer between the center bearing and the circlip on the mainshaft. The thickness of this washer was about the same as the existing one.”
Scott Ashworth: “replaced the worn synchro”
Thank you very much for all responses. Indeed, George has guided us to treat the topic in the forum. I will consult the great extension of files out there. Also, the site recommended by Keith: allexperts. However, I appreciate the guidance on practical experience to solve this problem. I will inform all of the findings.
|Gabriel, just wanted to make sure you know I'm not being lazy by not posting a direct answer (there are many possible causes and I'm no expert!). This, as many questions asked on the BBS have popped up many, many times over the years. There is a collective wealth of information in the archives. Some of the best comments/answers could have been made by individuals who no longer frequent the board, have moved on to other hobbies or cars, or even passed away. So you will likely find many possible solutions in there, and learn a lot as well. If not, let us know and we will come up with a list of other possibilities. George|
|Thank you very much George. You're right. There are many possible answers. At first I did not look in the appropriate manner. Now I've found all these:|
In the forums the answers are varied: See general wear, lockout balls, weak springs, worn bearings, washers, laygear end float, drive flange nut loose, selector mechanism in disrepair, Synchronized wrong,
poorly positioned sliding hub. And recommendations: Add a detent in the rail 1 / 2. Add a shim between the circlyp and the main bearing.
If I understand correctly. I found the previous post by Hugh Pite and seems very reasonable. The third gear quickly jump the faster you reduce speed, braking with the engine. If speed is reduced slightly, the third gear does not jump.
No damage can be seen in the third-synchronized, but may have wear.
I am very interested in your opinion and other feedback to help us solve this problem.
|I had this problem and I used an extra washer between the circlip and the center bearing as Hugh Pite suggested.|
The problem is that when you back off the power the pressure on the gears moves the sliding hub and the overlap with the dogs disappears(I think that is what they are called). It jumps out of gear.
Adding the washer fixed it.
|A J Clapham|
|Hello A J Clapham. |
I explain that to jump up, is in neutral. It does not jump out of gear.
If I understand correctly, the parts involved are (See picture):
58: Bearing, mainshaft center (127-000)
59: circlip, center mainshaft bearing (441-450)
60: washer, center mainshaft bearing (324-480)
61: circlip, center mainshaft bearing (326-070)
Is that correct?.
But, what is the circlip of the two there?.
|We may have a terminology difference. In my case the transmiision jumped from 3rd gear to neutral when I backed off the power.|
From memory it was washer 60 between the circlip 61 and bearing 59. I now have two washer 60.
|A J Clapham|
|Hi A J Clapham. |
Supposed to be that washer, but I needed confirmation.
Thank you very much and Merry Christmas.
|Gabriel, AJ Clapham's added washer #60 is what I used. It stopped the gearbox from jumping out of gear on deceleration.|
This thread was discussed between 17/12/2010 and 24/12/2010
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