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View Full Version : 4l80e shift hard in all gears


alderson95
11-10-2012, 17:20
my friend carlos has a 1997 chevy 6.5ltd that is a k3500. he still uses the truck on a daily bases on his farm. but he said when he took the truck to town to get feed he said the trans was shifting very hard at certen throtle positions. he stoped and added a half quart of dextron 3. went down the road a little ways and it was still shifting hard threw all gears. he said it seemed like it had no power after 1st gear. when he brought it to my house we rechecked the trany fluid and it seemed kind of brown in color. i hooked my obd 1&2 code reader up to the truck and it didnt show any dct's could this just be a old trany fillter that needs replace. the truck has about 200 thousand miles on it or so all original to my knoledge. also i did recomend that he get a new torque converter as i have been told that the origenal one on the truck had some sort of fault to it that was later corected in 1998. just wanted to see what you guys thought, any reaplys would be greatly apreciated.
DmaxMaverick
11-10-2012, 19:42
Service the tranny, and cross your fingers.... (although probably not the problem)

Start with a fresh fuel filter. Then, verify fuel delivery (lift pump operation). Either are the most common cause of low power and/or hard shifts.
alderson95
11-10-2012, 20:36
what do you mean by either im lost
DmaxMaverick
11-10-2012, 20:41
Sorry. Either, meaning the fuel filter and/or fuel lift pump operation.
phantom309
11-11-2012, 14:26
sounds like the force motor is stuck,.
force motor regulates trans pressure,.

Nick
alderson95
11-12-2012, 19:58
ok well we removed the tranny pan and replaced the filtter and fluid still doing the same the. but while driving the truck threw a code for the turbo sol valve. come to find out its not pulling the waste gate closed on the turbo. so we will replace it tommorow. also he has a small fule leak on i think #6 injection line so we will fix that as well. ill keep yall posted.
DmaxMaverick
11-12-2012, 20:50
Anything causing low power will cause hard shifts. A sloppy wastegate (for whatever reason) will do it.
alderson95
11-17-2012, 16:07
Ok we got the new waste gate valve trans is shifting smooth, but still seems low on power today we had the air fillter off the truck and starded it up. We kept hearing like a thumping sound from the turbo. It sounds almost like an exhuast leak. We jecked the down pipe and the manifolds and no leak. Could this be a stuck valve or bad injector? We will pull the valve covers and check the rocker arms tomorrow. And if it is a bad injector how can we tell?
DmaxMaverick
11-17-2012, 16:28
The noise is probably normal. 6.2/6.5L intake pulses are quite loud and authoritative. N/A engines have an OEM intake baffle (silencer), while the TD's are usually silenced by the turbo, intake plumbing, and air cleaner.

A bad injector will usually sound off with a loud knock sound. This is often mistaken for a rod-knock (by unknowing gasser mechanics). If you have a knock, you can test each injector by loosing the fuel line nut at the injector. This disables that cylinder. If the knock goes away, that's the cylinder with a bad injector. On DS4 engines (electronic), cylinders can be disabled individually with a Tech I/II scanner tool.
alderson95
11-19-2012, 15:00
ok if yall say it sound normal ill take yalls word for it. it may be because the new air fillter on it as well. he put a k&n airfillter on it about the same time it started making the noise. it just sounded weird, like it was an exhaust leak. but i mean the motor runs smooth no over heating or anything. by the way we did check the rocker arms, they seemed to be a little losse but im not to shure as to whats tolerable when it comes to this perticulay motor. any ideas thanx
scot5146
12-10-2012, 16:15
Whats your boost pressure? Did you check to see if the turbo has and movement in the turbine? Does it have the stock exhaust down pipe or is it upgraded?

Mike
scot5146
12-10-2012, 16:18
Whats your boost pressure? Did you check to see if the turbo has and movement in the turbine? Does it have the stock exhaust down pipe or is it upgraded?

Mike

After I checked the turbo out I would get a tech 2 and check the injectors... Mine had a similar problem with a bad injector but the turbo was going bad as well...

How many miles?

Mike