Reverse Gear Not Selecting 1998 Ls-400

[D.W. Brown]

I've read quite a bit on the forums about various tranny problems with varying results so let me add mine to the mix. :) The car is a 1998 LS-400 with about 130K miles on her.

Last week when I put the car into reverse I noticed it took a few seconds before it went into gear. Enough that I made a mental note of it. This morning I got into the car and was fine till I got about 5 miles up the road and pulled into parking lot. I went to back into space and it would not go in gear. The shifter went into reverse but car would not move, as if it was slipping.

I came home ran codes but only saw two that seemed more like OS2 sensor type codes and clear them before making mental note of numbers. I checked the tranny fluid and it looks clean and full. Checked history and shows a transmission servicing at a dealer this year in April 2015. I went ahead and ordered tranny fluid at $10.99 a quart (10 quarts). Going to flush it myself this evening but wanted some more opinions if I should try something else while under there.

[Exhaustgases]

Last time I got trans fluid at local Toyota dealer it was 5.61 a quart if memory serves.

Are you taking the pan off? I'm not sure if a solenoid is dedicated for reverse, if so look into that. Also selector switch.

[sha4000]

Did you check the fluid level after the car has warmed up and been driven for a while?

[D.W. Brown]

Well, it seemed for awhile the problem had gotten a little better. I wound up not doing the flush. Maybe once or twice a month reverse would slip a little, usually when first cranking the car up to leave the house. Today though it slipped bad. I had driven approx. 100 miles and got home stayed a couple of hours and went to run to store when it happened. I had to pull out forward though my yard. Once I got to store it seemed fine again. I don't believe it needs flushing since it was just done a year ago now. I find it hard to believe a mechanical problem with the gears, it's reverse after all. It's almost like it doesn't engage. What in the chain, if anything, could be causing reverse only not to engage properly? I know there are different solenoids (control, etc.) not really sure what each does or if one could affect reverse only. I may be waaayy off too as I know nothing about these tranny's. I'll rip my Mustangs Tremec TKO out and put it back in easy but this LS400 scares me.. LOL.

[D.W. Brown]

You know good question sha4000 will check it cold in the morning.

[sha4000]

Usually the clutch packs wear out and loosing reverse is the first indication of a tranny going bad. Although that is not the case all the time.

[D.W. Brown]

Ouch.. Anyway to tell for sure and any recommendations on a replacement (where from and avg. price). :(

[sha4000]

I would at least remind the transmission pan and check the filter out to see if it's clogged. Any shop is going to suggest a rebuild. To check it thoroughly the tranny would need to be dropped and opened up which would constitute a rebuild anyway. So I say drop the pan, clean the filter, full her back up and see what happens.