Tranny help

[TylerP53]

So when I put my transmission manually in 1st gear it revs high for a sec then feels like it’s shifting into 2nd. Then back to 1st. Anyone know what could cause this?

I only do it when I take it in the mud

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

@NickTransmissions is our resident transmission expert, and he will chime in with his thoughts and perspectives.

 

[NickTransmissions]

So when I put my transmission manually in 1st gear it revs high for a sec then feels like it’s shifting into 2nd. Then back to 1st. Anyone know what could cause this?

I only do it when I take it in the mud

If your rpms climb high enough in manual low, trans will force an upshift to second gear to protect engine and trans from damage. You need to do a gear command mod, which would give you manual low at any speed and rpm. Transgo reprogramming kits have these mods/parts so install that kit for your transmission and you wont have forced upshifts out of manaul low any more.

 

[rockola1971]

If tranny is stock and has had no work done internally, it will not last long mudding. You will end up burning up the clutches.

 

[Marky Dissod]

So when I put my transmission manually in 1st gear, it revs high for a sec, then feels like it’s shifting into 2nd, then back to 1st.
Anyone know what could cause this?
I only do it when I take it in the mud.

How fast are you going (MpH) when you shift manually into 1st?
You may be going fast enough to be on the pcm's border between 1st & 2nd.

Good idea to refresh ATF.