Joined: Oct 10, 2012 Posts: 310 Location: Toronto, Ontario, Canada
Posted: Mon Aug 03, 2015 2:54 pm Post subject: After clutch repair, tranny will not engage R or 1st
Gents,
Below is the description of the repair and subsequent issues of another M38 owner who does not have internet. It's quite a head scratcher…
Vehicle - 1953 CDN M38 - stock
Initial problem: clutch throw out bearing catastrophic failure. Also causing damage to bearing carrier.
Repair: removed power plant (engine, tranny, t case). Removed shift lever from transmission while it was in 2nd gear and T Case levers as per manual to get power plant out. Replaced entire clutch assembly, throw out bearing and carrier, pilot bearing.
Reinstalled power plant.
Problem during final test of repair: with engine running and T case in high or low, transmission will not go in to Reverse or First. The gears grind with the clutch engaged and will not engage. Second and Third engage normally. However, with T case in neutral Reverse and First will engage normally but T case then grinds trying to get in to high and will not engage.
Transmission finds all gears when engine not running.
Clutch adjustment is set correctly.
Even attempted full adjustment both ways with half turn increments. _________________ Jordan
Joined: Nov 24, 2010 Posts: 1390 Location: Orem, UT
Posted: Mon Aug 03, 2015 4:35 pm Post subject:
Sounds to me that the shift fork for 1st/rev didn't make it in it's groove on the gear when the shift tower was put back on. Very easy to have it happen as that gear just slides back and forth on the output shaft. The tower has a ball index so it may feel like it's going into gear. _________________ Brett
'51 M38
PHOTO DIARY OF MY BUILD
Joined: Oct 10, 2012 Posts: 310 Location: Toronto, Ontario, Canada
Posted: Mon Aug 03, 2015 5:34 pm Post subject:
I thought the same thing, but he specified that he just removed the shift lever and not the whole tower. Subsequently during trouble shooting he removed the tower and ensured that they were lining up properly. _________________ Jordan
Joined: Oct 10, 2012 Posts: 310 Location: Toronto, Ontario, Canada
Posted: Mon Aug 03, 2015 8:04 pm Post subject:
Update: functionality of second and third has been confirmed. The jeep even drove around the block with no issues in 2/3 but still won't find 1/R _________________ Jordan
Joined: Nov 24, 2010 Posts: 1390 Location: Orem, UT
Posted: Mon Aug 03, 2015 10:27 pm Post subject:
Ah, when you go to put that in, you can get the end of the rod in the wrong place. Have him pull it out and play with it, he might of missed getting the end in the right spot in the ends of the shift forks. I have done that. _________________ Brett
'51 M38
PHOTO DIARY OF MY BUILD
M-38: Install shift-lever back into the shift tower and secure with gearshift shift tower cap.
Other T-90s: Turn shift tower upside down and install shift lever into the tower make sure the positioning pin seats in the notch on the shift lever ball. Slide spring down over the shift lever and pop the spring over the retaining dogs one notch at a time with a large screw diver. This took me about 20 minutes the first time I did it, but now I can do it in about 2 minutes. Just don't loose patience with it.
Make sure the shift lever is to the inside of the rail before installation. Insert poppet ball spring and poppet balls into gearshift control housing on the low and reverse speed gears side. Insert the low and reverse speed gears shifter shaft into the gearshift control housing from the rear. If you have difficulty getting the shaft to go in more than about 3 inches inspect the interlock pin to make sure it is out of the way. Slide the low and reverse speed gears shifter fork onto the rail Note: it is easy to put this fork on backwards if you aren't careful. When it is properly installed the fork should fall evenly in the middle of the shift tower. Depress the poppet ball and poppet ball spring, using a blunt shaft (Do not use a sharp tipped instrument like a screwdriver or a nail.) and slide the rail in over the poppet ball to the second groove. This is the neutral position.
Make sure the shift lever is to the inside of this rail also before installation. Insert poppet ball spring and poppet balls into gearshift control housing on the second and high-speed gears side. Insert the second and high-speed gears shifter rail into the gearshift control housing from the rear. If you have difficulty getting the shaft to go in more than about 3 inches inspect the interlock pin to make sure it is out of the way. By now the interlock pin must fit into the detent notch in the low side rail. Note: This interlock pin is not like the one on the model 18 transfer-case. If you remove this pin it will allow the transmission to shift into two gears at the same time. This would effectively destroy a T-90. DO NOT REMOVE THE PIN. Slide the second and high-speed gears shifter fork onto the rail. Note: it is easy to put this fork on backwards if you aren't careful. When it is properly installed the fork should fall evenly in the middle of the shift tower. Depress the poppet ball and poppet ball spring, using a blunt shaft and slide the rail in over the poppet ball to the second groove. This is the neutral position.
Situate the shift lever so that it falls in between both the Low shift fork and the High shift notch. Secure both shifter forks onto the shifter shafts with shifter fork pins. For those with staked pins, flange the ends of the gearshift fork pins with a center punch.
M-38: Install 3/8-inch countersunk head pipe plugs in ends of gearshift control housing.
Place a small amount of sealant around the new gearshift rail hole expansion plugs into shifter shaft holes in the front end of gearshift control housing. If there is enough room in the ends of the rear shaft holes of your shifter, I recommend installing these plugs there too.
Joined: Oct 10, 2012 Posts: 310 Location: Toronto, Ontario, Canada
Posted: Tue Aug 04, 2015 12:38 pm Post subject:
Tested the shift to ensure it was actually engaging the tranny when the engine was off and it wasn't just the feeling of the poppets on the shift rails. While on axle stands, put the jeep into first with engine off and turned over. The engine turns the tires.
He also just sent this: " found in deeper test that one of the three dogs that go in the inner synchro gear is gone...upon thorough inspection of case - drained fluid etc. No dog found.... I think I know the rest of my day is going to be spent pulling the ****ing motor again " _________________ Jordan
Joined: Oct 10, 2012 Posts: 310 Location: Toronto, Ontario, Canada
Posted: Thu Aug 13, 2015 9:20 am Post subject:
It appears that the issue was in the clutch with the synchros explaining why the tranny would engage 2/3.
After ensuring the throw-out-bearing was engaging the carrier properly, adjusting the clutch pressure plate, and the clutch linkage, the problem has been solved.
A dragging clutch is usually the culprit when 1st / R are impossible to engage. In the future it may help others to pull the tranny cover, start the engine with the clutch depressed fully and if you have gears spinning in the tranny you have a clutch that is not releasing fully.
This is a very common issue when folks install the clutch release tube backwards because in that position there is not enough adjustment to ever allow the clutch to disengage completely. The short arm goes towards the frame and the long arm towards the bell housing. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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