Engine/Transmission (1994 - 1998) 98 auto questions

[DSeamans]

I know this has been answered on here, but I can't find the magic search words. My buddy has a 98 12v with, I believe, the 47re. When in D, I don't think its dropping to 1st when stopped. I think its actually starting in 3rd. The rpms will go up to 2000 and then the speed will slowly go up. At 45 -50mph, it locks up and goes like crazy. I think its the TQ slipping and not the bands/clutches. Manually putting it in first and shifting like a stick is better but not quite right. He said he can gas it with the brake on while stopped and it really slips. I'll tear anything apart and work on it, but autos are one thing I've never messed with. What does it sound like? Could it be solenoids or sensors or does he need to make an order with Goerends? I'll take any advice as it looks like time for me to learn autos! BTW, where's the third pedal with these?:-laf Oh yeah, no codes.



Thanks again,

Dave

 

[DSeamans]

Any ideas? I'm not complaining, I just have to look at it tomorrow.



Thanks,

Dave

 

[DBraunig]

More than likely it's the governor solenoid. you can hook up a pressure gauge (300psi) to the governor port (#2 in picture) on the trans and take it for a ride. should be less than 3psi sitting still and then rise smoothly with vehicle speed. Also, some were known to drop the band strut/anchor and cause a loss of 2nd gear. You'll have to drop the pan and have a look, but...

He said he can gas it with the brake on while stopped and it really slips.

After reading this i'd say the damage is done and regardless of what started the trouble the trans is coming out



Dave

 

[DBraunig]

forgot the picture



https://www.turbodieselregister.com...004-trans-test-port-question.html#post1853889



Dave

 

[EWalshak]

Dont let the auto trans intimidate you. If you have a good mechanical apptitude and can read a manual you can rebuild an auto trans. Thay really are not that difficult.

 

[DieselDoghouse]

Don't underestimate the peripherals messing with the A/T's mind - check TPS, speed sensor, engine crank sensor. They all flood data to the A/T part of the PCM. Based on a friends experience - some of the later 47RE's had solenoid harness faults. They thought they were facing major transmission rebuild - it was a wiring fault to the valve body and a quick solve.

 

[budnate]

pull the codes, see if it has "over voltage to transmission" sounds like limp mode, if it does read the trans tech here on trouble shooting it.

 

[RHestand]

DieselDoghouse,

RE:Solenoid wiring harness faults.

Were the problems caused by defective wires, bad connections, or what?

Also, were the problems repaired inside, or outside the trans. case/valve body?

budnate,

RE: Pulling codes. Can I pull the codes up by cycling ign. key off-on/ off-on etc? Or do I need a scanner?

TIA, Ray

 

[budnate]

go through all of this with his truck, https://www.turbodieselregister.com...7re-automatic-some-common-troubles-fixes.html



I had a combination plate with my truck, I had to go through everything on my truck, start at the tps and work your way out... its really not that hard just takes a little time to nail all the right voltages at the devices, once done you will be happy as it will run out like new again. biggest pain was nailing the right resitor for the trans, I am at a 220OHM =4. 60vdc to the trans now but I want to try a 210 ohm,



also you need to know the lower the voltage signal to the trans it increases line pressure and makes firmer shifts... my truck hit nice and clean on its shifts before and it now hits a tad to hard... so I want to sneak up the volts but not throw over voltage to the trans. pita!



you will need to go inside the trans to get at the solanoids if there bad... mine were intermitten as the over voltage deal had hurt them.



peace, B.

 

[RHestand]

budnate,

Thanks for the link, and all the work compiling all the info. in the link. With step by step instructions, no small chore.

I printed it, and it will go right in my Ram file, ready for an upcoming project.

Ray