Getrag Education.

[Rebel Ram]

I have been reading with great interest all the discusions on the 1st gen 5 speeds that I can find and following closely Bgilberts progress. I recently aquired a manual truck and have a concern. I read a thread while searching past posts to see if anyone had this symptom. I found one, but the end result was that they decided to just live with it. Well, I cannot.

What is happening is, At idle in neutral and clutch out the trans RATTLES. It is louder the warmer the truck gets. But if I increase RPMs just above idle, it will not rattle at all. At first I thought it was the clutch being shaken back and forth at low Rs but when I actually got under to try to isolate the problem, It is obvious that the sound is coming from the gear box toward the front.

The sound does not change as I put pressure on the clutch pedal until the clutch releases. Then it is silent. (input shaft stoped) The box shifts well and is quiet under power or deceleration, But will rattle again in gear if engine RPM is at idle and speed is matched so that there is slack in the drive train.

Other than this the box feels good and is smooth. Like I said, I have read many threads by searching "Getrag" and some names of experts keep popping up so I hope they (you) will help me out. I would like to have an idea as to what to prepare for as far as getting parts ready before pulling it apart. Thanks.



P. S. Some one on here had access to real manuals for these. Please advise.

 

[1stgen4evr]

Well it would be really hard to guess what is wrong from only that rattle. Before I pulled it apart I would inspect from both PTO covers and see if there is slack in the counter shaft bearings and to some extent you can check for the same on the main shaft. Pry the shaft(s) forward and aft and if there is any end play, it is time to pull it and do the preload. Even at 500k, mine doesn't rattle. Course I have re shimmed three times in its service life.



There could be significant wear on the input shaft at the clutch splines and at the pilot bearing which would allow some rotational rebounding that might manifest as a rattle. While you don't think it is the clutch, the rattle could be there and the noise manifest in the transmission. Quiet running and under load suggest that you don't have a huge$$$$ problem. But inattention to the problem could end in a $$$$$ problem.



You probably already know that I am completely satisfied with my experience regarding the Getrag. I hope that your service will turn out to be satisfactory as well. Include your email in a PM if you want more. You can search my post for more on the Getrag. But I am more that willing to discuss any of it with you.



James

 

[Paychk]

All of the above... may be the clutch disc dampener springs are broke.

 

[Rebel Ram]

Thanks for the quick responces. I'll do the PTO plate looksee. Any guidence for manuals or books?

 

[pepecat]

I have the info you are looking for pm me if you're interested

 

[WJune]

Hope you don't have the same 'Ghost' in your trans that I do. Iv'e isolated the rattle to the 3-4 shift fork rattling and wearing aluminum grindings in lube. Also brass from new syncros in lube. Just pulled trans for 5th time and clutch for 3rd. Rebuilt 2 trans, fixing their defects, new 13" disc, 2 differant flywheels with a new bearing and bushing in each one, new pilot shaft, and dial indicated both shafts, plus indicated every thing else in question. The only way I can get rid of most of the rattle is to leave some play in the input, but then it gets noisy an wears brs. Thought for sure it had to be a defective new disc or the machine shop messed up my flywheel, but no such luck ? Running out of things to check. The reason I call it a ghost is right now it comes an go's in neutral and 3-4-5. I test it now without transfer case on to save time.

Quickest way to see if you have this problem is to cut a hole in floor just big enough to remove shift cover. This allows inspection of forks an syncros without dropping trans etc. Run engine on starter, if rattle go's away, you got it. Good luck.

 

[pepecat]

well what are you using on the pilot shaft, bushing or bearing?

 

[MMiller]

What is your engine rpms at idle? If idle is too low then there will be all kinds of growling and such. Idle should be 800-850-even 900 is ok. I'm wondering as you say the noise goes away with a little rpms.



Michael

 

[MMiller]

What is your engine rpms at idle? If idle is too low then there will be all kinds of growling and such. Idle should be 800-850-even 900 is ok. I'm wondering as you say the noise goes away with a little increase in rpms.



Michael

 

[MMiller]

What is your engine rpms at idle? If idle is too low then there will be all kinds of growling and such. Idle should be 800-850-even 900 is ok. I'm wondering as you say the noise goes away with a little increase in rpms.



Michael

 

[WJune]

well what are you using on the pilot shaft, bushing or bearing?

I have tried both. Besides new brs an brass sync rings in 2 trans, the only thing I have changed from original is to modify flywheel for roller br and a new disc. As a last resort I changed flywheel to one with a new OEM brass bushing. With this last combination it seems like I had more difficulty getting trans in and out ? Frustrating thing is, I never find significate wear or damaged parts to give me a clue ? Original brass bushing on this truck was somewhat elongated, on the other truck it just crumbled when trans was removed.