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With a used t5 trannie, the car literally trembles in 4th and 5th gears.

The higher the speed, the greater the shaking. I've had a mechanic(from the selling dealership) witness it. He claims it could be the transmission. They put GEAR oil in and said that should stop the problem. It hasn't stopped at all.

Any ideas? I don't trust this dealership at all......unfortunately my son bought this car against my advice. It would be a fire-breathing beast except for the shaking.....

All advice would be greatly appreciated.

:eyebulge:
 
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I just read this somewhere, I wish I could remember where, but gear oil eats some kind of rings or something and basically screws the tranny. If I remember where I saw it I'll post a link.
 

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[but gear oil eats some kind of rings or something and basically screws the tranny.]
its b/c the oilers for the gears are too small for thick gear oil... so you dont get proper oiling. you must use ATF like these guys said.
 

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ATF fluid all the way. Replace it.

Are you sure the u joints are OK?
 

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Trembling

It may also be a driveshaft out of balance. Does this tremble change with RPM? If it does, and it is the same at (say) 50 MPH in 4 & 5, i.e. same driveshaft speed, then that may be it. Good luck.
 

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Yeah never put regular gear lube in a t-5. they have aluminum parts inside that need the atf rather than the gear lube which is meant for steel on steel lubing.
 

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Ok you replaced the tranny, did you match mark your drive shaft to the pinion flange? Did you check the bellhousing to engine dowel pins and align the tranny to the bell housing? Have the drive shaft ballanced also. Drain your tranny immediately. Make sure you get all gear oil out of it. Replace the fluid with DEXRON III. Your mainshaft synchro rings are fiber lined steel and if you use gear oil it will eat them up. I just finished replacing my non w/c with a w/c and I read up a little before I stabbed the new one in place. Here's a little light reading for ya from Ford Racing Performance Parts' website.



Q.: Clutch/Transmission Installation Tips For 1986 and Newer V-8 Mustangs

A.:

The flywheel to crankshaft bolts must be hand-torqued to 75-85 ft./lbs. (302/351W) and 54-64 ft./lbs. (4.6L) The 10.5" pressure plate bolts must be torqued to 12-24 ft./lbs. and 11" pressure plate bolts to 33 ft./lbs. + 1/4 turn.

Be sure to use the alignment dowels in the flywheels. Pressure plate bolts and alignment dowels for the 10.5" clutch can be purchased using PN M-6397-A302. Pressure plate bolts N808969-S100 and alignment dowels D1FZ-6397-B are for the 11" pressure plate.

Evenly tighten bolts in a circular direction one turn at a time. Bellhousing alignment is crucial for proper clutch and transmission function.

Due to production tolerances of engine blocks and bellhousings, it is possible for the transmission centerline and crankshaft centerline to be misaligned. Misalignment can cause transmission gear wear, transmission jumping out of gear, driveline vibration, clutch pedal vibration, pilot bearing noise, release bearing noise or excessive clutch spin time. It may also damage the pilot bearing, transmission mainshaft bearing and clutch hub. It will also cause harsh shifting.

Before installing the bellhousing, check the block mounting surface and bellhousing surfaces for nicks, dents, paint debris, etc. These are some things that could affect the accuracy of your measurements.



Q.: How do I check bellhousing alignment?

A.: The first step is to check bellhousing face runout. You are checking for parallelism of the back of the bellhousing to the back of the block. Install the dial indicator (as shown fig.1). Rotate the crankshaft and mark down the reading. Be sure to push the crankshaft against the thrust bearing for an accurate reading. Maximum runout is .010.

The next step is checking bellhousing bore runout. You are checking to see if the bellhousing bore centerline is aligned with crankshaft centerline. Reposition the dial indicator in the bellhousing bore (as shown fig. 2). Rotate the crankshaft and mark down the readings. Maximum out of concentricity is .015. If the bore runout is out of spec. install appropriate offset dowels.

Offset alignment dowels can be purchased from Lakewood.
.007 PN 15950
.014 PN 15960
.021 PN 15970
 

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KButter103 said:
Yeah never put regular gear lube in a t-5. they have aluminum parts inside that need the atf rather than the gear lube which is meant for steel on steel lubing.


You need to put 70W gear oil in a NWC T5 and DEX III (or GM Synthetic Tranny Fluid, also used in Tremecs) in a WC T5. Remember there are 4 variances of T5's from 79-95. 79-84 are NWC, 85-90 are the first WC's, 90-93 are the second WC's and 94-95 are the third WC's.
 

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Ratman418 said:
It trembles in higher rpms...the more rpms, the more trembling.....
I'd start to suspect the flywheel, and maybe the harmonic balancer. Has the car had an engine swap? if it has an engine from before 1982 or so, with the stock flywheel, it will do what you describe. I put a '79 302 in my '82 GT, using the '82 flywheel, and it did just what you said.
 
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