Engine/Transmission (1994 - 1998) 47RH Lockup problems

[SCosgriff]

My brother has a 97 CTD and I think there is a problem with the trans in it. The symptoms are that when towing in 3rd direct the torque convertor slips or it doesen't even lockup. When your in OD you can feel the convertor lockup but, in third you don't. Does the trans lockup differently in third and OD or is it that the torque can slip the clutch in 3rd but not OD.



It also shifts into OD at about 60 MPH which is much higher than my 95. There are no mods to his trans that we know of.

 

[Joe G.]

The '97 has a 47RE trans, not 47RH. This means that shifting is controlled by an electronic governor. If OD is locked out then the TC should lock up in 3rd. If OD is not locked out it will not lockup until it is in OD. That's true for both the 47RH and 47RE.

 

[SCosgriff]

If the trans only locks up if OD is off then his TC is slipping because the RPM stayed the same and the speed went up and down with the difficulty of the hills. Would this be a correct assumption.

 

[Joe G.]

The TC locks up in two conditions:



OD off it will lockup in 3rd.

OD on it will not lockup in 3d, it will lockup in OD.



If it is locked up and the RPM and MPH do not change in sync like in a manual trans and clutch then the TC clutch is slipping.



The thing here is IF it is locked up. You have to know that it did lockup before concluding that it is slipping.

 

[SCosgriff]

If the TC locks up in OD which it does would that be an indicator that the signal from the PCM is working OK



The other question would be how do I check to see if the TC is locking in 3rd. My 95 I can tell by the feel of it. His I can not feel the lock up in 3rd and the other curios thing is that his will shift at 60 MPH when OD is not locked out.

 

[Joe G.]

I have a '95 with a 47RH so I don't know how to trouble shoot the governor stuff on a 47RE. The trucks I have ridden in with a 47RE I could feel when it locked up the TC. It also will show on the tach when that happens.