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No Reverse on selespeed! HELP!

1560 Views 13 Replies 8 Participants Last post by  addo
Good day mates,

I have a selespeed gearbox, gears worked perfect, 1st and all other gears goes in fine and ryns lovely. About 4 months ago had installed a new selespeed pump next to the reservoir as it had stopped working. Now last 2 days reverse jumps out and goes into N. If I play with it a million times it will go in finally but it's a risk no one wants to take when I go somewhere for sure.

This is the codes generated
P176862- Hydraulic Circuit Accumulator discharged - signal compare failure

P17737B - Hydraulic Circuit Flow / Pressure - Low fluid Level

Car works great besides that, it should not be a big problem as forward it drives perfect and this is only as of 2 days now. Also I did a small vid last night, while i have it on idle the pump keeps coming on every few seconds but only like for 1 or 2 seconds and comes off and 2 little drops of fluid comes back in the bottle, sort of looks as though pressure constantly leaking as I know the pump when it comes on intermittently it will not move like that, so this is very strage.

Please Help Me, thanks

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Hi guys, here with an update, if you can asist further or advise, I have typed the beliw for another chat, with regards to no reverse now today I decided to see what is happening and sort the car oit, now there is no forward gears also attached with the new scan readout please assist
Minute Ago

Hello all, hope all is well, looking for some help.

About 4 months ago I got this car, there was a bas selespeed motor, changed it out with a new one as the old brushes plate was burned out. Since then car drives beautiful. Up till one week ago, reverse gear starting not going in and got worried. I will play with it until it went in for 2 days and decided something is very wrong.

The forward gears for those days worked beautiful and the R would go in so randomly and easy then other times nothing and the buzzer making noise. The car is doing 53k km Remember it has a new pump and I didn't change anything else as the car was in good condition.

Came today to start it and try sorting out to realise there is now no forward gears at all, pump primed for a bit long time when door was open but made no different to selecting gears. While the car is runing you would hear quick stints of the pump sort of mini primes, very very quick and short, then a few seconds another, it never did that before. I now scanned it again and I am attaching the photos. The scan with more is from today and the one with less is from 1 week ago. I looked at the pressure from the sensor via the scanner and now it's high as 72psi when those mini quick stints of the pump comes on, normally before when I check and ai changed the pump it normally will prime and stop around 50 or so and reprime when drops to close to 40 etc.

I will greatly appreacite some help as this is quite a disappointment now with covid etc. View attachment 958187 View attachment 958188
Did you replace the accumulator?

Accumulator stores pressure and "levels out" sudden pressure increases, which the pump coming online can cause.

You also might also need an EoL as not going to a single gear position suggests. I suspect the only-reverse failure was related to this, not the accumulator.

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Did not replace the accumulator as yet, I am going to order it this week. However now I am not getti g any gears, no forward and no reverse, pump was cha ged earlier in the year, I think it really can be the accumalator as you said. When I changed the pump the psi used to build like 40 psi and the pump wkll engage, then goes to like 50 or 51 etc then slowly decrease and repeat cycle. Now it goes to over 70 psi, so it really leans towards the accumalator filling with oil I pressume. Let me mnow your thoughts. Thanks much
As David C. said, just replace the accumulator first. Diagnose further is you have other problems as you won't be doing that without accumulator working anyway.

Pressure jumping to those levels means your accumulator likely has a punctured diaphgram. As fluids don't compress, pressure jumps as soon as the pump comes online, then cuts off due to overpressure.

If accumulator was working, the pressure would build up more steadily as the gas inside the accumulator compresses.

Selespeed needs pressure between 35-55 bars to operate. No accumulator, no pressure standing by.

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