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eric remington
eric remington,
Category: Transmissions
Satisfied Customers: 1537
Experience:  mechanic/service advisor at topline auto
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Customer Question

Need to know if there is an expert on transmissions online. I rebuilt a 4L30E transmission on a 2002 Isuzu Trooper with a 3.5L V6 and it doesn't shift properly. The 1-2 band, torque converter, all shift solenoids, clutches, some steels and of course seals and gaskets have been replaced. The transmission will not go into 4th and overdrive when cold, not sure its because of the trans temp sensor in the pan but it will finally go into overdrive when fully warmed up. Next when warmed up it shifts all gears 1st to 2nd around 10 to 12 mph then 2nd to 3rd around 18 to 20 mph then at around 28 to 30 mph it will shift into 4th and full lockup at almost the same time. Between 20 and 30 or around 25 mph then engine is revving high around 2500 rpm's before it finally goes into 4th and overdrive. I drove it again today and found out if you shift it manually it will work but still has high revs before it goes into overdrive. If you drive with selector in Manual 3rd it will shift from 1st to 4th gear and it does this consistently. When you put selector to D it will take a second to go into overdrive. I am totally stumped on this and have pulled the transmission twice to fix the problem and still it works the same. I've replaced the pump bushing, the bushing in the 2nd drum and another in the rear case. Also installed a shift kit which I thought would help but the shifts are still hard to notice but you can barely feel them.
Submitted: 8 months ago.
Category: Transmissions
Expert:  hdgene replied 8 months ago.

Hello, and thank you for using Just Answer! My name is***** me a few moments to review your question and Ill do my best to assist you.

Expert:  hdgene replied 8 months ago.

Hello, it sounds like you may have an issue with a valve hanging int he valve body since it does have all the gears, but not shifting at the right shift times. You didnt mention what happened to the trans that it needed rebuilt or if this was a problem prior to the repair.

Customer: replied 8 months ago.
Cool, also there were no codes generated and my hand scanner finds none. Also I had my friend who rebuilds transmissions drive the car and he didnt think anything is wrong other than the fan clutch is making a lot of noise matching the engine RPM's but I still dont believe the transmission is working correctly. It initially came in with smoke clutches in the 2nd gear drum. I rebuilt this same transmission 3 years ago when it burned the same clutches.
Expert:  hdgene replied 8 months ago.

Ok, look at the valve body, check the valves, if that looks ok air check the clutches. Make sure there is no leaks. If you get into the internals of the trans, make sure the clutch packs arent too tight.

Expert:  hdgene replied 8 months ago.

If you didnt flush the cooler, some debris may have made its way into the main control valve body or trans itself.

Customer: replied 8 months ago.
I've double and triple checked the valves and they all move freely. When I installed the shift kit components there were a couple of springs that go into the main pump for pressure that I couldnt do because I didnt remove the transmission again. I pressure checked each drum and they held air before reassembly. I tightened up the clutch pack in the 2nd drum but the overrun pack had only 1 clutch disc and I added another for clearance. I know this transmission has problems with case warpage, 1-2 band burn, 1-2 servo leakage. The trans seems to shift just at the wrong time in 4th and overdrive. I dont know why I get 4th when in manual 3rd. How do you know if the converter is going out or having a problem?
Customer: replied 8 months ago.
I did flush the lines and replaced the torque converter. I cant tell at 20 to 25 mph running around 2500 rpm's if its slipping or the converter isnt holding.
Expert:  hdgene replied 8 months ago.

You modified the valve body with a shift kit? but not all of it?

Customer: replied 8 months ago.
I modified everything with the shift kit except for the main pressure springs in the front pump. I'm wondering if one or both of my sprags are having issues. I dont think I have any engine braking in 1st gear and I'm not sure about the front one thats in the 3rd gear drum. If they dont hold what the conditions are. I checked them this last time to go the proper way by my manual but if they dont hold under load. Any thoughts?
Expert:  hdgene replied 8 months ago.
That could very well be. Or fluid is by passing a check ball in the valve body. The pump springs should be done in order for the shift kit to work properly and increase line pressure for firm shifts.
Customer: replied 8 months ago.
I can't do the pump springs unless I remove the transmission. When I performed a line pressure test it was around 145-150. If the O/D roller clutch or sprag is week or going bad what will that cause? I don't believe I was feeling engine braking very much in 1st or 2nd but both sprags checked out when I went through the trans the 2nd time. On the spec sheet it shows the O/D Roller clutch is in LD or locked in drive for all ranges except 4th which is supposed to be FW or free wheeling.
Expert:  hdgene replied 8 months ago.
They pretty much work or don't work when it comes to one way clutches. So either it locks or doesn't. No real in between. The line pressure is the same in all gears including reverse? There should be a difference depending on the type of shift kit you put in. Reverse is always higher pressure than drive
Customer: replied 8 months ago.
I guess this isn't working out for me. I'm not getting the answers I really need and would like another advisor or a full refund.
Customer: replied 8 months ago.
I haven't heard anything from anybody in over a week and need to see about how to get a refund as I haven't found any answers to my questions.
Expert:  eric remington replied 8 months ago.

maybe if you drive it codes will appear. if its not a hard fault it may take a number of failures to set code s

Expert:  eric remington replied 8 months ago.

maybe a defective torque converter...can u monitor pressures during shifts?

Expert:  eric remington replied 8 months ago.

sorry I see you did replace converter....sometimes there are defects ....if you drove it long enough you may get codes..may take a certain amount of failures b4 it kicks a code...pending code?

Expert:  eric remington replied 8 months ago.

are pressures up to snuff during shifts? KI assume you flushed cooler. strange that the vehicle wont go into overdrive till reaches certain temp. that unusual. not enough pressure ot problem with tq converter. is solenoid being commanded on when test driving with cold engine? can u monitor it?

Expert:  eric remington replied 8 months ago.

monitor pressures during faulty shifts and observe pressure and tq converter commands when cold when trans should be shifting into overdrive. Do yo have specs? any band adjustments? all shifting seem to improve when warm?

Customer: replied 8 months ago.
No codes at all. Already pulled trans again for the 3rd time to see if I missed anything. When I did check pressures they were around 150 to 160 but when I did drive it, it wouldnt go into lockup until it fully warmed up. There is a sensor as part of the wiring loom in the big pan. There is only 1 band adjustment for the 1-2 band torque to 40 inch lbs then back off 5 turns. Transmission shifts the same when cold or hot, just seems to work really hard after it shifts from 3rd to 4th from about 20 to 30 mph running at 2500rpms. Engine revs but not really picking up speed. Then at 28 to 30 mph it will shift into 4th and lockup at same time everytime. After I pulled trans I found no burnt clutches anywhere and the band looks good just a small amount of metal in pan enough to pickup with small magnetic screwdriver and some black stuff on magnet in pan. Initially I found the bushing for the 3rd gear drum worn thats in the intermediate pump worn out, I replaced and also replaced thrust washer worn out between 2nd and 3rd drum. I have no transmission scanner that I can hookup while I'm driving. I only have specs from the overhaul kit.
Expert:  eric remington replied 8 months ago.

ok can you drive it with scanner hooked up cold or do you have trans all apart?

Expert:  eric remington replied 8 months ago.

wont pick up speed? are you sure you don't have an engine performance issue?

Expert:  eric remington replied 8 months ago.

restricted exhaust improper mech ign timing>? are you a professional mechanic?

Customer: replied 8 months ago.
No I dont have an expensive scanner active scanner that will work when driving other than one that will read and erase codes. Engine is running fine it has plenty of power, no misses or performance issues. I rebuilt the trans 3 years ago when the 2nd gear drum burned the clutches. Then it came in again when the third gear went out and I found the intermediate pump bushing worn out which is the only thing that seals the 3rd gear shaft. Also I posted that when your in 3rd manual that the trans will shift into 4th gear which it shouldnt. This is only when its hot or normal running temp. I've heard that the selector switch sometimes goes bad on these units but I have no way to test it. I used to be a professional mechanic, been working on cars for over 40 years for several dealers.
Expert:  eric remington replied 8 months ago.

SO WE DONT KNOW WHAT PRESSURES ARE WHEN DRIVING...I WILL OPT OUT IF YOU DONT KNOW YOUR PRESSURES VIA SCAN TOOL AND OR GAUGE HOW ARE YOU FGOING TO DIAGNOSE YOUR PROBLEMs