Triumph Repair/TR7 1st gear grind
QUESTION: Hi Howard, I bought a 1982 TR7 5spd not running due to broken clutch release fork. Release fork is fix but it is hard to get it in to 1st gear I just get a grinding noise but when it goes in seems to run fine, putting pressure on the gear shift lever helps I think. Reverse and all other gears work fine. My question, could there be something out of adjustment or if 1st gear bad? Thanks in advance.
ANSWER: Hi Mark,
Try this, First check to see that the idle is below 1000 RPM and then hold the clutch on the floor for 5 to 10 seconds and put the shift lever into 2nd gear. Now move the shift lever from 2nd on up to 1st gear. You should note no gear clash. Now put it in to neutral and let the clutch pedal out then push it to the floor and hold it there for 5 to 10 seconds and then put it into 1st gear. don't rev the engine at any time through these tests, it must stay at a low idle.
If you did not get any gear clash going into 2nd from neutral but did get gear clash going into 1st then the syncro on 1st gear is worn.
You must never depress the clutch pedal and quickly put it into any gear normally, even when everything is new. The reason is that when the clutch pedal is up and the engine is idling the clutch disk is spinning at engine speed and so is the first motion shaft (input shaft# The first motion shaft is turning the whole lay gear and that in-turn is spinning every gear in the gear box except the reverse idler gear. The tail shaft #output shaft# is stationary with the driveshaft. When you depress the clutch pedal you disengage the clutch disk from the flywheel and pressure plate but it was spinning at 700 to 900 RPM and it has every gear attached to it so they are like a flywheel and will keep spinning for a while #about 5 to 10 seconds# depending on what weight and temperature the gearbox oil is. That is why it is important to let all the gears and the clutch disk coast to a stop before putting it into gear.
If there is a problem with the clutch not fully disengaging then you would note gear clash with reverse and sometime if it is bad enough it will clash in all gears from neutral.
If only 1st gear is affected then it is most likely due to bad driving habits from the previous owner by quickly depressing the clutch and quickly pushing it into 1st gear. Thus a 1st gear syncro worn out. If this is the case you can drive the car for it's life time by depressing the clutch and wait 5 to 10 seconds and put it in 2nd gear and then quickly into 1st. The only problem with driving a car with a worn syncro you need to learn to correctly down shift. #a lost art these days)
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QUESTION: Hello Howard, thanks for the quick reply.
You said "If this is the case you can drive the car for it's life time by depressing the clutch and wait 5 to 10 seconds and put it in 2nd gear and then quickly into 1st." Does that mean get it rolling in 2nd and quickly put it in first? Because just going from second to first with the clutch pressed dosen't seem to help, as soon as I release the clutch it grinds. My driveway is a slight slop when I do get it to engage in 1st I can drive up, press the clutch roll down and do it again with out problem, would this be keeping with the syncro problem. It works great when it does engage 1st but is nearly impossible to get it.
ANSWER: Mark, No, when you depress the clutch (with it idling below 1000 RPM) wait 5 to 10 seconds and put it into 2nd gear. Do not roll forward. Now you have it in 2nd gear and idling and the pedal on the floor, put it from 2nd into first quickly. You should not get any gear clash when first going into 2nd and none going from 2nd to 1st.
Here is a test of the clutch, on level ground with the hand brake off and foot off of the foot brake. After you get it into 1st gear and at idle and clutch pedal depressed all the way, let it idle for a minute to see if the car "Creeps" forward. If it does you have a clutch release problem which contributes to gear clashing from neutral to 1st.
When you are in 2nd gear with the clutch pedal depressed and the car is stopped. ALL gears in the transmission are also STOPPED, so sliding the shift lever from 2nd gear quickly to 1st gear it is impossible to get any kind of gear grinding be cause ALL gears and shafts are stationary "stopped". Absolutely nothing is moving inside the gearbox at that point.
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QUESTION: Thanks for clarifying That Howard, There is no Problem getting the transmission into the first gear position with the clutch pressed, its only when I take my foot off the clutch pedal when the grinding happens, sorry for the confusion. Thank you for your time.
Oh! that is much different. It sounds like it didn't shift all the way in gear. The way that it shifts into a gear is that a sliding hub assembly does all of the engaging as the gears are in constant mesh all the time and are never actually out of gear. The sliding hub assembly is slid on it's hub to push on a brass syncro ring that acts like a small clutch to get the gear turning at the same speed as the hub assembly then a spline on the outer hub engages a similar spline on the gear after the syncro (if it did it's job# gets the two to the same speed. Thus no grinding.
If for some reason the hub didn't go all the way engaged with the spline on the gear then it grinds because it didn't slid far enough to engage.
The only reason that don't engage because of an outside problem is when for some reason the shift lever is fouling on the tunnel. #transmission or motor mount problem) This can easily be checked by removing the shift boot and look to see that the shift lever it not hitting when 1st gear is engaged.
If that is ok Then you are going to have to remove the transmission and go inside. If there is no extra loose free play in the shift linkage, You will have to open up the transmission as you have the 5 speed gearbox and it does not have a inspection cover like the 4 speed box did.
If it is inside, it sounds like you either have a badly worn 1st/2nd shift fork or a worn out spacer on the main shaft allowing too much forward/aft movement of the gears and hub assembly.