T-5 won't let me go over 55 mph on 4th

[juniorfeo]

I have a 84 CJ7 with a AMC 258 i6 / 4.2l and T-5 thing is that when I hit the freeway I shift 1 2 3 and on 4 jeep starts to shake and won't let me get to 5th is on 4th at 55mph at 2400 rpm don't know if it might be the Transmission or the fact that the jeep has a 4" lift on 33s and a gear ratio of 3.31s thats how I purchased the jeep any help would be gladly appreciated thanks

 

[jeepardy]

Little more info please, lots of things can cause this. With the tires and lift your stretching the limit on both the gears and drive shafts. Can you ever get it into 5th, even when standing still? Have the drive shafts been lengthened? Are there shims in the springs and has the tranfer case been lowered? When you say shake, is it a shake or a real bad vibration. otherwords do you feel it in your hands through the steering wheel or through your butt, through the seats?

 

[juniorfeo]

5th goes in fine at a still tranfercase was lowered no shims on springs and shaking is bad not vibration literally rough shaking like the Transmission gona fall apart changed all the mounts already engine and Transmission and driveshafts weren't lenghtened

 

[BusaDave9]

Vibration at speed usually means something is out of balance. I'm not so sure it's the tranny.
Maybe you lost a wheel weight. How are the wheels, wheel bearings. Is the rear drive shaft bent? I assume you are in 2WD with the hubs unlocked so the front drive shaft is not rotating.

 

[juniorfeo]

Wheels balanced and I see no bends on the driveshaft I checked the wheel bearings about a month a go and yeah I'm on 2wd

 

[jeepardy]

5th goes in fine at a still tranfercase was lowered no shims on springs and shaking is bad not vibration literally rough shaking like the Transmission gona fall apart changed all the mounts already engine and Transmission and driveshafts weren't lenghtened

I'd check the pinion bearing and rear output bearing on the T/C. If you lowered the T/C but didn't raise (shimmed) the diff you threw off your driveline angles.


That vibration energy has to be dissipated somewhere, most likely the output bearing. If driven over time it will ruin the bearings and move onto another area. You'll also need to shim the diff to get those angles as small as possible, and the same

 

[juniorfeo]

Thanks I will do thats asap see if it helps out

 

[Cheepjeep85]

I'm gonna say warped wheel, tire has a broken belt, and lastly possibly could be bent axle tube and shaft. If its shaking that bad it has to be close to where the rubber meets the road. You gotta think there is nothing in the Transmission that's heavy enough to cause the jeep to shake violently enough, so you can't drive it normally. I suppose it could be a driveshaft but 9 times out of 10 its a high frequency vibration and generally a drive shaft is also not heavy enough to cause the kind of vibration you describe.
DROOOID2

 

[Old Dog]

Does it do it at 55 no matter what gear?
Does it shake in 4th no matter how fast you are going?
We need to narrow this down to either speed or 4th. gear.

 

[juniorfeo]

@old dog i shift fine thru 3rd gear once I shift to 4th it goes the once I hit 55 it start the shaking! @ cheep nothing bent shafts are straight tires are new jeep has never been offroad neither plan to fix this problem first

 

[Cheepjeep85]

I'm just saying that sounds like a big vibratio, and it would have to be something to do with your wheels, tires, or axles and when I say axles, ball joints, bearings, etc might cause it to. Just because it has new tires doesn't mean one isn't bad. Or a wheel isn't warped.

DROOOID2