[LukeA]

Yesterday I was driving it and am now finding it to slip in pretty much all conditions. I noticed a couple slips from start and also from 1-2 and 3-4 in addition to the 2-3 which has also gotten worse. Also, downshifting from 3-2 I'm experiencing hesitations and "jerking." Any ideas? I'm wondering if I should be checking electrical connections but have the feeling it may be time for a rebuilt or remanufactured transmission. The truck is in really good shape (other than these transmission problems) and I'd like to keep it for a long time so I see it as worth the investment if that's what it comes down to.

...also got the flashing trouble light: pending fault code is P1870

 

[LukeA]

@Buster28 I just found this about P1870:

P1870 Transmission Component Slipping (TCC Stuck OFF) B ON Flash

Would you agree this would indicate that I should replace the TCC solenoid - or could this possibly mean something else?

 

[Buster28]

A 3 to 2 down shift requires the 3rd clutch to release and the reaction drum Brake Band to apply, in a 2 to 3 up shift the opposite happens. The Brake Band servo is controlled by the Brake Band solenoid that uses a Pulse Width Modulated (PWM) control signal. The Brake Band solenoid controls the rate at which the Brake Band Servo applies and releases the Brake Band depending on the duty cycle of the PWM control signal which changes with load conditions. You could try replacing the Brake Band solenoid and the TCC solenoid. If that fails to improve the shift quality installing an AR5 manual transmission is a good option.

BTW a 00-02 Trooper uses a PWM TCC solenoid that is different than the On/Off type.

 

[LukeA]

Thanks again (as always great information). I would actually really like to put in a manual transmission but was sort of intimidated by the magnitude of that project - also was thinking it might be difficult to get one as there just weren't many in the U.S. it seems to me. I will do some research into that. I'm guessing that involves also replacing the PCM correct?

 

[Buster28]

If you remove the 4L30e the Powertrain Control Module (PCM) will detect failures when it runs diagnostic tests and keep the CEL Illuminated. You can't pass state emission tests with the the CEL Illuminated. So if you live in a state that performs ODB II emission tests you absolutely need to replace the PCM. Also, be aware that a 98-99 Trooper PCM is not the same as 00-02 Trooper PCM. The AR5 is applicable 98-02 Trooper.

 

[LukeA]

If you remove the 4L30e the Powertrain Control Module (PCM) will detect failures when it runs diagnostic tests and keep the CEL Illuminated. You can't pass state emission tests with the the CEL Illuminated. So if you live in a state that performs ODB II emission tests you absolutely need to replace the PCM. Also, be aware that a 98-99 Trooper PCM is not the same as 00-02 Trooper PCM. The AR5 is applicable 98-02 Trooper.

I'm in SD so the CEL wouldn't be a problem for inspections (yet). I see that the AR5 was in quite a few vehicles - including the GMC colorado/canyon which would probably be a lot more common in the U.S than troopers. Do you know if a transmission from other vehicles like that will work in a trooper or are there subtle differences (variants of AR5's) between the different vehicles?

 

[Buster28]

I don't know if the bell housing used with a GM vehicle AR5 will bolt up to an Isuzu 3.5L and I don't recall anyone in forum stating they installed a non Isuzu AR5.

 

[Enemigo]

Burried somewhere in this thread should be the info you need for using alternative AR5 transmissions. If I remember, seems like you could just swap bellhousings.

Engine Swap Bellhousings - Jeeps-Offroad.com Bulletin Board

Engine Swap Bellhousings Tech. Articles

web.archive.org

 

[Buster28]

The AR5 bellhousing is removable but where are you going to find an Isuzu AR5 bellhousing?

 

[LukeA]

Here's an interesting article: P1870 Revisited
That would suggest that I should be replacing the sleeve in the TCC control valve body. Any idea how I get to that?

 

[Buster28]

You have to remove the transmission from the truck and then partially disassemble the transmission to get to the hydraulic pump body to replace the sleeve.
Btw, P1870 doesn't always indicate a TCC problem, it more generally means the transmission input rpm does not match the output rpm with the TCC applied in 3rd gear (1:1 ratio). So if the Overrun Clutch or the 2nd Clutch or 3rd Clutch slips P1870 may set.
Additionally, that wiz-bang unnecessary TCC setup is why you have to use a 00-02 Trooper transmission in your truck. Install a Rodeo transmission and the TCC will not work properly, Install the wrong Torque Converter and the TCC friction material will burn up.