Transmission died...........

[ogrice]

My NV4500 2wd manual trans gave up. The only gears that i can get are reverse and 4th gear. The trans started acting like the clutch needed to be bled, so I did and it acted normal for a few days. Without any warning it popped out of overdrive on the freeway and I couldn't get it back into any gear without powershifting. I replaced the master cylinder and the slave cylinder. It shifted normal for a one day. The following day it did the same thing popping out of gear, but I couldn't powershift without getting some real bad grinding sounds going into any gear. The clutch pedal felt normal, but no amount of pumping it worked. The trans has 22k miles since I had it rebuilt with a total of 230k lifetime miles. I'm thinking that the synchros are done. I'll post what I find.

I run a solid flywheel with stage II clutch kit. My 6.5l TD engine runs about 50hp and 100ft/lbs over stock. I've already tracked down and purchased a replacement trans.

Who else out there has had to change out a busted manual trans in there rig.? What caused your trans to go kaput.?

[jackrabbit]

On my 85 6.2L I had to replace the orginal transmission (4sp with OD) 2 times. It went out the third time and I replaced it with the NV4500 and I haven't had any problems since. I wasn't told what was going wrong with this transmission.

I picked up the NV4500 at the factory in Muncie and they told me that the only problems they had seen with that transmission (NV4500) is that the wrong transmission oil would be used when replaced and it would then take out the bearings due to over heating.

He said that the trans oil was a specially made synthetic that had a much higher temperature range than normal. He gave me that part number and said only use this fluid. I haven't changed the tran fluid since I got it, but I only have around 80,000 miles on this one.

[ogrice]

Bearings went out due to heat from having the wrong tranny oil. #?%$#!!. I got a feeling that I'm going to find heat damage somewhere/everywhere. I was finding the gear case pretty warm too. Maybe abnormally high, but i'm no expert to tell how hot is bad.

[ogrice]

Dropped out the trans and found that the clutch disc exploded. Hopefully the input shaft is still o.k. Going to keep and install the replacement trans, but now I have to get a new clutch. Well, I'm going to make sure I now why this happened before I put the truck back on the road. The old trans is going to get inspected later on. I'll hold onto it for good measure.

[Turbo Al]

I think the trans is probably just fine -- they do run a little warm esp when towing that's why I put a temp guage in mine and cut back on the throttle when it hits 200 degrees.
I have never heard of a Chevy destroying a NV4500 -- these are tough trans. A few Dodge boys I know of have destroyed them (considerablely more power in a hopped up Cummins) and they started to put an additional quart of oil in the trans and that seems to help out a lot.
Al

[ogrice]

I think your right turbo al. I think that I spent the cash for a replacemant trans a little premature. I'm going to get the o.g. trans checked out, If nothing is wrong, then i've just made very expensive oversight.

[Turbo Al]

The GOOD news is that if it is indeed O K and the original 1993 trans then it is in BIG demand with the 4x4/ rock crawler crowd because of the extremely low first gear ratio.
Al

[ogrice]

With the insight that you just told me; i'll make sure that its good, hold onto it till the warranty of the newer trans is about up, then probably sell it. The truck is in the northwest in Washington right now. Should be easy enough to find a taker for a fair sum.